fix: 首次提交

SettingsLib/src/com/android/settingslib/inputmethod/InputMethodAndSubtypeEnablerManagerCompat.java

@@ -0,0 +1,265 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package com.android.settingslib.inputmethod;
+
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.content.res.Configuration;
+import android.text.TextUtils;
+import android.view.inputmethod.InputMethodInfo;
+import android.view.inputmethod.InputMethodManager;
+import android.view.inputmethod.InputMethodSubtype;
+
+import androidx.preference.Preference;
+import androidx.preference.PreferenceCategory;
+import androidx.preference.PreferenceFragmentCompat;
+import androidx.preference.PreferenceScreen;
+import androidx.preference.TwoStatePreference;
+
+import com.android.settingslib.R;
+
+import java.text.Collator;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+
+public class InputMethodAndSubtypeEnablerManagerCompat implements
+        Preference.OnPreferenceChangeListener {
+
+    private final PreferenceFragmentCompat mFragment;
+
+    private boolean mHaveHardKeyboard;
+    private final HashMap<String, List<Preference>> mInputMethodAndSubtypePrefsMap =
+            new HashMap<>();
+    private final HashMap<String, TwoStatePreference> mAutoSelectionPrefsMap = new HashMap<>();
+    private InputMethodManager mImm;
+    // TODO: Change mInputMethodInfoList to Map
+    private List<InputMethodInfo> mInputMethodInfoList;
+    private final Collator mCollator = Collator.getInstance();
+
+    public InputMethodAndSubtypeEnablerManagerCompat(PreferenceFragmentCompat fragment) {
+        mFragment = fragment;
+        mImm = fragment.getContext().getSystemService(InputMethodManager.class);
+
+        mInputMethodInfoList = mImm.getInputMethodList();
+    }
+
+    public void init(PreferenceFragmentCompat fragment, String targetImi, PreferenceScreen root) {
+        final Configuration config = fragment.getResources().getConfiguration();
+        mHaveHardKeyboard = (config.keyboard == Configuration.KEYBOARD_QWERTY);
+
+        for (final InputMethodInfo imi : mInputMethodInfoList) {
+            // Add subtype preferences of this IME when it is specified or no IME is specified.
+            if (imi.getId().equals(targetImi) || TextUtils.isEmpty(targetImi)) {
+                addInputMethodSubtypePreferences(fragment, imi, root);
+            }
+        }
+    }
+
+    public void refresh(Context context, PreferenceFragmentCompat fragment) {
+        // Refresh internal states in mInputMethodSettingValues to keep the latest
+        // "InputMethodInfo"s and "InputMethodSubtype"s
+        InputMethodSettingValuesWrapper
+                .getInstance(context).refreshAllInputMethodAndSubtypes();
+        InputMethodAndSubtypeUtilCompat.loadInputMethodSubtypeList(fragment,
+                context.getContentResolver(), mInputMethodInfoList, mInputMethodAndSubtypePrefsMap);
+        updateAutoSelectionPreferences();
+    }
+
+    public void save(Context context, PreferenceFragmentCompat fragment) {
+        InputMethodAndSubtypeUtilCompat.saveInputMethodSubtypeList(fragment,
+                context.getContentResolver(), mInputMethodInfoList, mHaveHardKeyboard);
+    }
+
+    @Override
+    public boolean onPreferenceChange(final Preference pref, final Object newValue) {
+        if (!(newValue instanceof Boolean)) {
+            return true; // Invoke default behavior.
+        }
+        final boolean isChecking = (Boolean) newValue;
+        for (final String imiId : mAutoSelectionPrefsMap.keySet()) {
+            // An auto select subtype preference is changing.
+            if (mAutoSelectionPrefsMap.get(imiId) == pref) {
+                final TwoStatePreference autoSelectionPref = (TwoStatePreference) pref;
+                autoSelectionPref.setChecked(isChecking);
+                // Enable or disable subtypes depending on the auto selection preference.
+                setAutoSelectionSubtypesEnabled(imiId, autoSelectionPref.isChecked());
+                return false;
+            }
+        }
+        // A subtype preference is changing.
+        if (pref instanceof InputMethodSubtypePreference) {
+            final InputMethodSubtypePreference subtypePref = (InputMethodSubtypePreference) pref;
+            subtypePref.setChecked(isChecking);
+            if (!subtypePref.isChecked()) {
+                // It takes care of the case where no subtypes are explicitly enabled then the auto
+                // selection preference is going to be checked.
+                updateAutoSelectionPreferences();
+            }
+            return false;
+        }
+        return true; // Invoke default behavior.
+    }
+
+    private void addInputMethodSubtypePreferences(PreferenceFragmentCompat fragment,
+            InputMethodInfo imi, final PreferenceScreen root) {
+        Context prefContext = fragment.getPreferenceManager().getContext();
+
+        final int subtypeCount = imi.getSubtypeCount();
+        if (subtypeCount <= 1) {
+            return;
+        }
+        final String imiId = imi.getId();
+        final PreferenceCategory keyboardSettingsCategory =
+                new PreferenceCategory(prefContext);
+        root.addPreference(keyboardSettingsCategory);
+        final PackageManager pm = prefContext.getPackageManager();
+        final CharSequence label = imi.loadLabel(pm);
+
+        keyboardSettingsCategory.setTitle(label);
+        keyboardSettingsCategory.setKey(imiId);
+        // TODO: Use toggle Preference if images are ready.
+        final TwoStatePreference autoSelectionPref =
+                new SwitchWithNoTextPreference(prefContext);
+        mAutoSelectionPrefsMap.put(imiId, autoSelectionPref);
+        keyboardSettingsCategory.addPreference(autoSelectionPref);
+        autoSelectionPref.setOnPreferenceChangeListener(this);
+
+        final PreferenceCategory activeInputMethodsCategory =
+                new PreferenceCategory(prefContext);
+        activeInputMethodsCategory.setTitle(R.string.active_input_method_subtypes);
+        root.addPreference(activeInputMethodsCategory);
+
+        CharSequence autoSubtypeLabel = null;
+        final ArrayList<Preference> subtypePreferences = new ArrayList<>();
+        for (int index = 0; index < subtypeCount; ++index) {
+            final InputMethodSubtype subtype = imi.getSubtypeAt(index);
+            if (subtype.overridesImplicitlyEnabledSubtype()) {
+                if (autoSubtypeLabel == null) {
+                    autoSubtypeLabel = InputMethodAndSubtypeUtil.getSubtypeLocaleNameAsSentence(
+                            subtype, prefContext, imi);
+                }
+            } else {
+                final Preference subtypePref = new InputMethodSubtypePreference(
+                        prefContext, subtype, imi);
+                subtypePreferences.add(subtypePref);
+            }
+        }
+        subtypePreferences.sort((lhs, rhs) -> {
+            if (lhs instanceof InputMethodSubtypePreference) {
+                return ((InputMethodSubtypePreference) lhs).compareTo(rhs, mCollator);
+            }
+            return lhs.compareTo(rhs);
+        });
+        for (final Preference pref : subtypePreferences) {
+            activeInputMethodsCategory.addPreference(pref);
+            pref.setOnPreferenceChangeListener(this);
+            InputMethodAndSubtypeUtil.removeUnnecessaryNonPersistentPreference(pref);
+        }
+        mInputMethodAndSubtypePrefsMap.put(imiId, subtypePreferences);
+        if (TextUtils.isEmpty(autoSubtypeLabel)) {
+            autoSelectionPref.setTitle(
+                    R.string.use_system_language_to_select_input_method_subtypes);
+        } else {
+            autoSelectionPref.setTitle(autoSubtypeLabel);
+        }
+    }
+
+    private boolean isNoSubtypesExplicitlySelected(final String imiId) {
+        final List<Preference> subtypePrefs = mInputMethodAndSubtypePrefsMap.get(imiId);
+        for (final Preference pref : subtypePrefs) {
+            if (pref instanceof TwoStatePreference && ((TwoStatePreference) pref).isChecked()) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private void setAutoSelectionSubtypesEnabled(final String imiId,
+            final boolean autoSelectionEnabled) {
+        final TwoStatePreference autoSelectionPref = mAutoSelectionPrefsMap.get(imiId);
+        if (autoSelectionPref == null) {
+            return;
+        }
+        autoSelectionPref.setChecked(autoSelectionEnabled);
+        final List<Preference> subtypePrefs = mInputMethodAndSubtypePrefsMap.get(imiId);
+        for (final Preference pref : subtypePrefs) {
+            if (pref instanceof TwoStatePreference) {
+                // When autoSelectionEnabled is true, all subtype prefs need to be disabled with
+                // implicitly checked subtypes. In case of false, all subtype prefs need to be
+                // enabled.
+                pref.setEnabled(!autoSelectionEnabled);
+                if (autoSelectionEnabled) {
+                    ((TwoStatePreference) pref).setChecked(false);
+                }
+            }
+        }
+        if (autoSelectionEnabled) {
+            InputMethodAndSubtypeUtilCompat.saveInputMethodSubtypeList(
+                    mFragment, mFragment.getContext().getContentResolver(),
+                    mInputMethodInfoList, mHaveHardKeyboard);
+            updateImplicitlyEnabledSubtypes(imiId);
+        }
+    }
+
+    private void updateImplicitlyEnabledSubtypes(final String targetImiId) {
+        // When targetImiId is null, apply to all subtypes of all IMEs
+        for (final InputMethodInfo imi : mInputMethodInfoList) {
+            final String imiId = imi.getId();
+            final TwoStatePreference autoSelectionPref = mAutoSelectionPrefsMap.get(imiId);
+            // No need to update implicitly enabled subtypes when the user has unchecked the
+            // "subtype auto selection".
+            if (autoSelectionPref == null || !autoSelectionPref.isChecked()) {
+                continue;
+            }
+            if (imiId.equals(targetImiId) || targetImiId == null) {
+                updateImplicitlyEnabledSubtypesOf(imi);
+            }
+        }
+    }
+
+    private void updateImplicitlyEnabledSubtypesOf(final InputMethodInfo imi) {
+        final String imiId = imi.getId();
+        final List<Preference> subtypePrefs = mInputMethodAndSubtypePrefsMap.get(imiId);
+        final List<InputMethodSubtype> implicitlyEnabledSubtypes =
+                mImm.getEnabledInputMethodSubtypeList(imi, true);
+        if (subtypePrefs == null || implicitlyEnabledSubtypes == null) {
+            return;
+        }
+        for (final Preference pref : subtypePrefs) {
+            if (!(pref instanceof TwoStatePreference)) {
+                continue;
+            }
+            final TwoStatePreference subtypePref = (TwoStatePreference) pref;
+            subtypePref.setChecked(false);
+            for (final InputMethodSubtype subtype : implicitlyEnabledSubtypes) {
+                final String implicitlyEnabledSubtypePrefKey = imiId + subtype.hashCode();
+                if (subtypePref.getKey().equals(implicitlyEnabledSubtypePrefKey)) {
+                    subtypePref.setChecked(true);
+                    break;
+                }
+            }
+        }
+    }
+
+    private void updateAutoSelectionPreferences() {
+        for (final String imiId : mInputMethodAndSubtypePrefsMap.keySet()) {
+            setAutoSelectionSubtypesEnabled(imiId, isNoSubtypesExplicitlySelected(imiId));
+        }
+        updateImplicitlyEnabledSubtypes(null /* targetImiId */  /* check */);
+    }
+}

SettingsLib/src/com/android/settingslib/inputmethod/InputMethodAndSubtypeUtil.java

@@ -0,0 +1,436 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package com.android.settingslib.inputmethod;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.content.res.Configuration;
+import android.icu.text.ListFormatter;
+import android.provider.Settings;
+import android.provider.Settings.SettingNotFoundException;
+import android.text.TextUtils;
+import android.util.Log;
+import android.view.inputmethod.InputMethodInfo;
+import android.view.inputmethod.InputMethodSubtype;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.preference.Preference;
+import androidx.preference.PreferenceFragment;
+import androidx.preference.PreferenceScreen;
+import androidx.preference.TwoStatePreference;
+
+import com.android.internal.app.LocaleHelper;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+// TODO: Consolidate this with {@link InputMethodSettingValuesWrapper}.
+public class InputMethodAndSubtypeUtil {
+
+    private static final boolean DEBUG = false;
+    private static final String TAG = "InputMethdAndSubtypeUtl";
+
+    private static final String SUBTYPE_MODE_KEYBOARD = "keyboard";
+    private static final char INPUT_METHOD_SEPARATER = ':';
+    private static final char INPUT_METHOD_SUBTYPE_SEPARATER = ';';
+    private static final int NOT_A_SUBTYPE_ID = -1;
+
+    private static final TextUtils.SimpleStringSplitter sStringInputMethodSplitter
+            = new TextUtils.SimpleStringSplitter(INPUT_METHOD_SEPARATER);
+
+    private static final TextUtils.SimpleStringSplitter sStringInputMethodSubtypeSplitter
+            = new TextUtils.SimpleStringSplitter(INPUT_METHOD_SUBTYPE_SEPARATER);
+
+    // InputMethods and subtypes are saved in the settings as follows:
+    // ime0;subtype0;subtype1:ime1;subtype0:ime2:ime3;subtype0;subtype1
+    public static String buildInputMethodsAndSubtypesString(
+            final HashMap<String, HashSet<String>> imeToSubtypesMap) {
+        final StringBuilder builder = new StringBuilder();
+        for (final String imi : imeToSubtypesMap.keySet()) {
+            if (builder.length() > 0) {
+                builder.append(INPUT_METHOD_SEPARATER);
+            }
+            final HashSet<String> subtypeIdSet = imeToSubtypesMap.get(imi);
+            builder.append(imi);
+            for (final String subtypeId : subtypeIdSet) {
+                builder.append(INPUT_METHOD_SUBTYPE_SEPARATER).append(subtypeId);
+            }
+        }
+        return builder.toString();
+    }
+
+    private static String buildInputMethodsString(final HashSet<String> imiList) {
+        final StringBuilder builder = new StringBuilder();
+        for (final String imi : imiList) {
+            if (builder.length() > 0) {
+                builder.append(INPUT_METHOD_SEPARATER);
+            }
+            builder.append(imi);
+        }
+        return builder.toString();
+    }
+
+    private static int getInputMethodSubtypeSelected(ContentResolver resolver) {
+        try {
+            return Settings.Secure.getInt(resolver,
+                    Settings.Secure.SELECTED_INPUT_METHOD_SUBTYPE);
+        } catch (SettingNotFoundException e) {
+            return NOT_A_SUBTYPE_ID;
+        }
+    }
+
+    private static boolean isInputMethodSubtypeSelected(ContentResolver resolver) {
+        return getInputMethodSubtypeSelected(resolver) != NOT_A_SUBTYPE_ID;
+    }
+
+    private static void putSelectedInputMethodSubtype(ContentResolver resolver, int hashCode) {
+        Settings.Secure.putInt(resolver, Settings.Secure.SELECTED_INPUT_METHOD_SUBTYPE, hashCode);
+    }
+
+    // Needs to modify InputMethodManageService if you want to change the format of saved string.
+    static HashMap<String, HashSet<String>> getEnabledInputMethodsAndSubtypeList(
+            ContentResolver resolver) {
+        final String enabledInputMethodsStr = Settings.Secure.getString(
+                resolver, Settings.Secure.ENABLED_INPUT_METHODS);
+        if (DEBUG) {
+            Log.d(TAG, "--- Load enabled input methods: " + enabledInputMethodsStr);
+        }
+        return parseInputMethodsAndSubtypesString(enabledInputMethodsStr);
+    }
+
+    public static HashMap<String, HashSet<String>> parseInputMethodsAndSubtypesString(
+            final String inputMethodsAndSubtypesString) {
+        final HashMap<String, HashSet<String>> subtypesMap = new HashMap<>();
+        if (TextUtils.isEmpty(inputMethodsAndSubtypesString)) {
+            return subtypesMap;
+        }
+        sStringInputMethodSplitter.setString(inputMethodsAndSubtypesString);
+        while (sStringInputMethodSplitter.hasNext()) {
+            final String nextImsStr = sStringInputMethodSplitter.next();
+            sStringInputMethodSubtypeSplitter.setString(nextImsStr);
+            if (sStringInputMethodSubtypeSplitter.hasNext()) {
+                final HashSet<String> subtypeIdSet = new HashSet<>();
+                // The first element is {@link InputMethodInfoId}.
+                final String imiId = sStringInputMethodSubtypeSplitter.next();
+                while (sStringInputMethodSubtypeSplitter.hasNext()) {
+                    subtypeIdSet.add(sStringInputMethodSubtypeSplitter.next());
+                }
+                subtypesMap.put(imiId, subtypeIdSet);
+            }
+        }
+        return subtypesMap;
+    }
+
+    private static HashSet<String> getDisabledSystemIMEs(ContentResolver resolver) {
+        HashSet<String> set = new HashSet<>();
+        String disabledIMEsStr = Settings.Secure.getString(
+                resolver, Settings.Secure.DISABLED_SYSTEM_INPUT_METHODS);
+        if (TextUtils.isEmpty(disabledIMEsStr)) {
+            return set;
+        }
+        sStringInputMethodSplitter.setString(disabledIMEsStr);
+        while(sStringInputMethodSplitter.hasNext()) {
+            set.add(sStringInputMethodSplitter.next());
+        }
+        return set;
+    }
+
+    public static void saveInputMethodSubtypeList(PreferenceFragment context,
+            ContentResolver resolver, List<InputMethodInfo> inputMethodInfos,
+            boolean hasHardKeyboard) {
+        String currentInputMethodId = Settings.Secure.getString(resolver,
+                Settings.Secure.DEFAULT_INPUT_METHOD);
+        final int selectedInputMethodSubtype = getInputMethodSubtypeSelected(resolver);
+        final HashMap<String, HashSet<String>> enabledIMEsAndSubtypesMap =
+                getEnabledInputMethodsAndSubtypeList(resolver);
+        final HashSet<String> disabledSystemIMEs = getDisabledSystemIMEs(resolver);
+
+        boolean needsToResetSelectedSubtype = false;
+        for (final InputMethodInfo imi : inputMethodInfos) {
+            final String imiId = imi.getId();
+            final Preference pref = context.findPreference(imiId);
+            if (pref == null) {
+                continue;
+            }
+            // In the choose input method screen or in the subtype enabler screen,
+            // <code>pref</code> is an instance of TwoStatePreference.
+            final boolean isImeChecked = (pref instanceof TwoStatePreference) ?
+                    ((TwoStatePreference) pref).isChecked()
+                    : enabledIMEsAndSubtypesMap.containsKey(imiId);
+            final boolean isCurrentInputMethod = imiId.equals(currentInputMethodId);
+            final boolean systemIme = imi.isSystem();
+            if ((!hasHardKeyboard && InputMethodSettingValuesWrapper.getInstance(
+                    context.getActivity()).isAlwaysCheckedIme(imi))
+                    || isImeChecked) {
+                if (!enabledIMEsAndSubtypesMap.containsKey(imiId)) {
+                    // imiId has just been enabled
+                    enabledIMEsAndSubtypesMap.put(imiId, new HashSet<>());
+                }
+                final HashSet<String> subtypesSet = enabledIMEsAndSubtypesMap.get(imiId);
+
+                boolean subtypePrefFound = false;
+                final int subtypeCount = imi.getSubtypeCount();
+                for (int i = 0; i < subtypeCount; ++i) {
+                    final InputMethodSubtype subtype = imi.getSubtypeAt(i);
+                    final String subtypeHashCodeStr = String.valueOf(subtype.hashCode());
+                    final TwoStatePreference subtypePref = (TwoStatePreference) context
+                            .findPreference(imiId + subtypeHashCodeStr);
+                    // In the Configure input method screen which does not have subtype preferences.
+                    if (subtypePref == null) {
+                        continue;
+                    }
+                    if (!subtypePrefFound) {
+                        // Once subtype preference is found, subtypeSet needs to be cleared.
+                        // Because of system change, hashCode value could have been changed.
+                        subtypesSet.clear();
+                        // If selected subtype preference is disabled, needs to reset.
+                        needsToResetSelectedSubtype = true;
+                        subtypePrefFound = true;
+                    }
+                    // Checking <code>subtypePref.isEnabled()</code> is insufficient to determine
+                    // whether the user manually enabled this subtype or not.  Implicitly-enabled
+                    // subtypes are also checked just as an indicator to users.  We also need to
+                    // check <code>subtypePref.isEnabled()</code> so that only manually enabled
+                    // subtypes can be saved here.
+                    if (subtypePref.isEnabled() && subtypePref.isChecked()) {
+                        subtypesSet.add(subtypeHashCodeStr);
+                        if (isCurrentInputMethod) {
+                            if (selectedInputMethodSubtype == subtype.hashCode()) {
+                                // Selected subtype is still enabled, there is no need to reset
+                                // selected subtype.
+                                needsToResetSelectedSubtype = false;
+                            }
+                        }
+                    } else {
+                        subtypesSet.remove(subtypeHashCodeStr);
+                    }
+                }
+            } else {
+                enabledIMEsAndSubtypesMap.remove(imiId);
+                if (isCurrentInputMethod) {
+                    // We are processing the current input method, but found that it's not enabled.
+                    // This means that the current input method has been uninstalled.
+                    // If currentInputMethod is already uninstalled, InputMethodManagerService will
+                    // find the applicable IME from the history and the system locale.
+                    if (DEBUG) {
+                        Log.d(TAG, "Current IME was uninstalled or disabled.");
+                    }
+                    currentInputMethodId = null;
+                }
+            }
+            // If it's a disabled system ime, add it to the disabled list so that it
+            // doesn't get enabled automatically on any changes to the package list
+            if (systemIme && hasHardKeyboard) {
+                if (disabledSystemIMEs.contains(imiId)) {
+                    if (isImeChecked) {
+                        disabledSystemIMEs.remove(imiId);
+                    }
+                } else {
+                    if (!isImeChecked) {
+                        disabledSystemIMEs.add(imiId);
+                    }
+                }
+            }
+        }
+
+        final String enabledIMEsAndSubtypesString = buildInputMethodsAndSubtypesString(
+                enabledIMEsAndSubtypesMap);
+        final String disabledSystemIMEsString = buildInputMethodsString(disabledSystemIMEs);
+        if (DEBUG) {
+            Log.d(TAG, "--- Save enabled inputmethod settings. :" + enabledIMEsAndSubtypesString);
+            Log.d(TAG, "--- Save disabled system inputmethod settings. :"
+                    + disabledSystemIMEsString);
+            Log.d(TAG, "--- Save default inputmethod settings. :" + currentInputMethodId);
+            Log.d(TAG, "--- Needs to reset the selected subtype :" + needsToResetSelectedSubtype);
+            Log.d(TAG, "--- Subtype is selected :" + isInputMethodSubtypeSelected(resolver));
+        }
+
+        // Redefines SelectedSubtype when all subtypes are unchecked or there is no subtype
+        // selected. And if the selected subtype of the current input method was disabled,
+        // We should reset the selected input method's subtype.
+        if (needsToResetSelectedSubtype || !isInputMethodSubtypeSelected(resolver)) {
+            if (DEBUG) {
+                Log.d(TAG, "--- Reset inputmethod subtype because it's not defined.");
+            }
+            putSelectedInputMethodSubtype(resolver, NOT_A_SUBTYPE_ID);
+        }
+
+        Settings.Secure.putString(resolver,
+                Settings.Secure.ENABLED_INPUT_METHODS, enabledIMEsAndSubtypesString);
+        if (disabledSystemIMEsString.length() > 0) {
+            Settings.Secure.putString(resolver, Settings.Secure.DISABLED_SYSTEM_INPUT_METHODS,
+                    disabledSystemIMEsString);
+        }
+        // If the current input method is unset, InputMethodManagerService will find the applicable
+        // IME from the history and the system locale.
+        Settings.Secure.putString(resolver, Settings.Secure.DEFAULT_INPUT_METHOD,
+                currentInputMethodId != null ? currentInputMethodId : "");
+    }
+
+    public static void loadInputMethodSubtypeList(final PreferenceFragment context,
+            final ContentResolver resolver, final List<InputMethodInfo> inputMethodInfos,
+            final Map<String, List<Preference>> inputMethodPrefsMap) {
+        final HashMap<String, HashSet<String>> enabledSubtypes =
+                getEnabledInputMethodsAndSubtypeList(resolver);
+
+        for (final InputMethodInfo imi : inputMethodInfos) {
+            final String imiId = imi.getId();
+            final Preference pref = context.findPreference(imiId);
+            if (pref instanceof TwoStatePreference) {
+                final TwoStatePreference subtypePref = (TwoStatePreference) pref;
+                final boolean isEnabled = enabledSubtypes.containsKey(imiId);
+                subtypePref.setChecked(isEnabled);
+                if (inputMethodPrefsMap != null) {
+                    for (final Preference childPref: inputMethodPrefsMap.get(imiId)) {
+                        childPref.setEnabled(isEnabled);
+                    }
+                }
+                setSubtypesPreferenceEnabled(context, inputMethodInfos, imiId, isEnabled);
+            }
+        }
+        updateSubtypesPreferenceChecked(context, inputMethodInfos, enabledSubtypes);
+    }
+
+    private static void setSubtypesPreferenceEnabled(final PreferenceFragment context,
+            final List<InputMethodInfo> inputMethodProperties, final String id,
+            final boolean enabled) {
+        final PreferenceScreen preferenceScreen = context.getPreferenceScreen();
+        for (final InputMethodInfo imi : inputMethodProperties) {
+            if (id.equals(imi.getId())) {
+                final int subtypeCount = imi.getSubtypeCount();
+                for (int i = 0; i < subtypeCount; ++i) {
+                    final InputMethodSubtype subtype = imi.getSubtypeAt(i);
+                    final TwoStatePreference pref = (TwoStatePreference) preferenceScreen
+                            .findPreference(id + subtype.hashCode());
+                    if (pref != null) {
+                        pref.setEnabled(enabled);
+                    }
+                }
+            }
+        }
+    }
+
+    private static void updateSubtypesPreferenceChecked(final PreferenceFragment context,
+            final List<InputMethodInfo> inputMethodProperties,
+            final HashMap<String, HashSet<String>> enabledSubtypes) {
+        final PreferenceScreen preferenceScreen = context.getPreferenceScreen();
+        for (final InputMethodInfo imi : inputMethodProperties) {
+            final String id = imi.getId();
+            if (!enabledSubtypes.containsKey(id)) {
+                // There is no need to enable/disable subtypes of disabled IMEs.
+                continue;
+            }
+            final HashSet<String> enabledSubtypesSet = enabledSubtypes.get(id);
+            final int subtypeCount = imi.getSubtypeCount();
+            for (int i = 0; i < subtypeCount; ++i) {
+                final InputMethodSubtype subtype = imi.getSubtypeAt(i);
+                final String hashCode = String.valueOf(subtype.hashCode());
+                if (DEBUG) {
+                    Log.d(TAG, "--- Set checked state: " + "id" + ", " + hashCode + ", "
+                            + enabledSubtypesSet.contains(hashCode));
+                }
+                final TwoStatePreference pref = (TwoStatePreference) preferenceScreen
+                        .findPreference(id + hashCode);
+                if (pref != null) {
+                    pref.setChecked(enabledSubtypesSet.contains(hashCode));
+                }
+            }
+        }
+    }
+
+    public static void removeUnnecessaryNonPersistentPreference(final Preference pref) {
+        final String key = pref.getKey();
+        if (pref.isPersistent() || key == null) {
+            return;
+        }
+        final SharedPreferences prefs = pref.getSharedPreferences();
+        if (prefs != null && prefs.contains(key)) {
+            prefs.edit().remove(key).apply();
+        }
+    }
+
+    @NonNull
+    public static String getSubtypeLocaleNameAsSentence(@Nullable InputMethodSubtype subtype,
+            @NonNull final Context context, @NonNull final InputMethodInfo inputMethodInfo) {
+        if (subtype == null) {
+            return "";
+        }
+        final Locale locale = getDisplayLocale(context);
+        final CharSequence subtypeName = subtype.getDisplayName(context,
+                inputMethodInfo.getPackageName(), inputMethodInfo.getServiceInfo()
+                        .applicationInfo);
+        return LocaleHelper.toSentenceCase(subtypeName.toString(), locale);
+    }
+
+    @NonNull
+    public static String getSubtypeLocaleNameListAsSentence(
+            @NonNull final List<InputMethodSubtype> subtypes, @NonNull final Context context,
+            @NonNull final InputMethodInfo inputMethodInfo) {
+        if (subtypes.isEmpty()) {
+            return "";
+        }
+        final Locale locale = getDisplayLocale(context);
+        final int subtypeCount = subtypes.size();
+        final CharSequence[] subtypeNames = new CharSequence[subtypeCount];
+        for (int i = 0; i < subtypeCount; i++) {
+            subtypeNames[i] = subtypes.get(i).getDisplayName(context,
+                    inputMethodInfo.getPackageName(), inputMethodInfo.getServiceInfo()
+                            .applicationInfo);
+        }
+        return LocaleHelper.toSentenceCase(
+                ListFormatter.getInstance(locale).format((Object[]) subtypeNames), locale);
+    }
+
+    @NonNull
+    private static Locale getDisplayLocale(@Nullable final Context context) {
+        if (context == null) {
+            return Locale.getDefault();
+        }
+        if (context.getResources() == null) {
+            return Locale.getDefault();
+        }
+        final Configuration configuration = context.getResources().getConfiguration();
+        if (configuration == null) {
+            return Locale.getDefault();
+        }
+        final Locale configurationLocale = configuration.getLocales().get(0);
+        if (configurationLocale == null) {
+            return Locale.getDefault();
+        }
+        return configurationLocale;
+    }
+
+    public static boolean isValidNonAuxAsciiCapableIme(InputMethodInfo imi) {
+        if (imi.isAuxiliaryIme()) {
+            return false;
+        }
+        final int subtypeCount = imi.getSubtypeCount();
+        for (int i = 0; i < subtypeCount; ++i) {
+            final InputMethodSubtype subtype = imi.getSubtypeAt(i);
+            if (SUBTYPE_MODE_KEYBOARD.equalsIgnoreCase(subtype.getMode())
+                    && subtype.isAsciiCapable()) {
+                return true;
+            }
+        }
+        return false;
+    }
+}

SettingsLib/src/com/android/settingslib/inputmethod/InputMethodAndSubtypeUtilCompat.java

@@ -0,0 +1,479 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package com.android.settingslib.inputmethod;
+
+import android.annotation.UserIdInt;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.content.res.Configuration;
+import android.icu.text.ListFormatter;
+import android.os.UserHandle;
+import android.provider.Settings;
+import android.provider.Settings.SettingNotFoundException;
+import android.text.TextUtils;
+import android.util.Log;
+import android.view.inputmethod.InputMethodInfo;
+import android.view.inputmethod.InputMethodSubtype;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.preference.Preference;
+import androidx.preference.PreferenceFragmentCompat;
+import androidx.preference.PreferenceScreen;
+import androidx.preference.TwoStatePreference;
+
+import com.android.internal.app.LocaleHelper;
+import com.android.settingslib.PrimarySwitchPreference;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+// TODO: Consolidate this with {@link InputMethodSettingValuesWrapper}.
+public class InputMethodAndSubtypeUtilCompat {
+
+    private static final boolean DEBUG = false;
+    private static final String TAG = "InputMethdAndSubtypeUtlCompat";
+
+    private static final String SUBTYPE_MODE_KEYBOARD = "keyboard";
+    private static final char INPUT_METHOD_SEPARATER = ':';
+    private static final char INPUT_METHOD_SUBTYPE_SEPARATER = ';';
+    private static final int NOT_A_SUBTYPE_ID = -1;
+
+    private static final TextUtils.SimpleStringSplitter sStringInputMethodSplitter
+            = new TextUtils.SimpleStringSplitter(INPUT_METHOD_SEPARATER);
+
+    private static final TextUtils.SimpleStringSplitter sStringInputMethodSubtypeSplitter
+            = new TextUtils.SimpleStringSplitter(INPUT_METHOD_SUBTYPE_SEPARATER);
+
+    // InputMethods and subtypes are saved in the settings as follows:
+    // ime0;subtype0;subtype1:ime1;subtype0:ime2:ime3;subtype0;subtype1
+    public static String buildInputMethodsAndSubtypesString(
+            final HashMap<String, HashSet<String>> imeToSubtypesMap) {
+        final StringBuilder builder = new StringBuilder();
+        for (final String imi : imeToSubtypesMap.keySet()) {
+            if (builder.length() > 0) {
+                builder.append(INPUT_METHOD_SEPARATER);
+            }
+            final HashSet<String> subtypeIdSet = imeToSubtypesMap.get(imi);
+            builder.append(imi);
+            for (final String subtypeId : subtypeIdSet) {
+                builder.append(INPUT_METHOD_SUBTYPE_SEPARATER).append(subtypeId);
+            }
+        }
+        return builder.toString();
+    }
+
+    private static String buildInputMethodsString(final HashSet<String> imiList) {
+        final StringBuilder builder = new StringBuilder();
+        for (final String imi : imiList) {
+            if (builder.length() > 0) {
+                builder.append(INPUT_METHOD_SEPARATER);
+            }
+            builder.append(imi);
+        }
+        return builder.toString();
+    }
+
+    private static int getInputMethodSubtypeSelected(ContentResolver resolver) {
+        try {
+            return Settings.Secure.getInt(resolver,
+                    Settings.Secure.SELECTED_INPUT_METHOD_SUBTYPE);
+        } catch (SettingNotFoundException e) {
+            return NOT_A_SUBTYPE_ID;
+        }
+    }
+
+    private static boolean isInputMethodSubtypeSelected(ContentResolver resolver) {
+        return getInputMethodSubtypeSelected(resolver) != NOT_A_SUBTYPE_ID;
+    }
+
+    private static void putSelectedInputMethodSubtype(ContentResolver resolver, int hashCode) {
+        Settings.Secure.putInt(resolver, Settings.Secure.SELECTED_INPUT_METHOD_SUBTYPE, hashCode);
+    }
+
+    // Needs to modify InputMethodManageService if you want to change the format of saved string.
+    static HashMap<String, HashSet<String>> getEnabledInputMethodsAndSubtypeList(
+            ContentResolver resolver) {
+        final String enabledInputMethodsStr = Settings.Secure.getString(
+                resolver, Settings.Secure.ENABLED_INPUT_METHODS);
+        if (DEBUG) {
+            Log.d(TAG, "--- Load enabled input methods: " + enabledInputMethodsStr);
+        }
+        return parseInputMethodsAndSubtypesString(enabledInputMethodsStr);
+    }
+
+    public static HashMap<String, HashSet<String>> parseInputMethodsAndSubtypesString(
+            final String inputMethodsAndSubtypesString) {
+        final HashMap<String, HashSet<String>> subtypesMap = new HashMap<>();
+        if (TextUtils.isEmpty(inputMethodsAndSubtypesString)) {
+            return subtypesMap;
+        }
+        sStringInputMethodSplitter.setString(inputMethodsAndSubtypesString);
+        while (sStringInputMethodSplitter.hasNext()) {
+            final String nextImsStr = sStringInputMethodSplitter.next();
+            sStringInputMethodSubtypeSplitter.setString(nextImsStr);
+            if (sStringInputMethodSubtypeSplitter.hasNext()) {
+                final HashSet<String> subtypeIdSet = new HashSet<>();
+                // The first element is {@link InputMethodInfoId}.
+                final String imiId = sStringInputMethodSubtypeSplitter.next();
+                while (sStringInputMethodSubtypeSplitter.hasNext()) {
+                    subtypeIdSet.add(sStringInputMethodSubtypeSplitter.next());
+                }
+                subtypesMap.put(imiId, subtypeIdSet);
+            }
+        }
+        return subtypesMap;
+    }
+
+    private static HashSet<String> getDisabledSystemIMEs(ContentResolver resolver) {
+        HashSet<String> set = new HashSet<>();
+        String disabledIMEsStr = Settings.Secure.getString(
+                resolver, Settings.Secure.DISABLED_SYSTEM_INPUT_METHODS);
+        if (TextUtils.isEmpty(disabledIMEsStr)) {
+            return set;
+        }
+        sStringInputMethodSplitter.setString(disabledIMEsStr);
+        while(sStringInputMethodSplitter.hasNext()) {
+            set.add(sStringInputMethodSplitter.next());
+        }
+        return set;
+    }
+
+    /**
+     * Save the enabled/disabled input methods and selected subtype states into system settings.
+     *
+     * @param fragment The preference fragment user interact with.
+     * @param resolver The {@link ContentResolver} used to access the database.
+     * @param inputMethodInfos The list of {@link InputMethodInfo} to be checked.
+     * @param hasHardKeyboard {@code true} if the device has the hardware keyboard.
+     */
+    public static void saveInputMethodSubtypeList(PreferenceFragmentCompat fragment,
+            ContentResolver resolver, List<InputMethodInfo> inputMethodInfos,
+            boolean hasHardKeyboard) {
+        saveInputMethodSubtypeListForUserInternal(
+                fragment, resolver, inputMethodInfos, hasHardKeyboard, UserHandle.myUserId());
+    }
+
+    /**
+     * Save the enabled/disabled input methods and selected subtype states into system settings as
+     * given userId.
+     *
+     * @param fragment The preference fragment user interact with.
+     * @param resolver The {@link ContentResolver} used to access the database.
+     * @param inputMethodInfos The list of {@link InputMethodInfo} to be checked.
+     * @param hasHardKeyboard {@code true} if the device has the hardware keyboard.
+     * @param userId The given userId
+     */
+    public static void saveInputMethodSubtypeListForUser(PreferenceFragmentCompat fragment,
+            ContentResolver resolver, List<InputMethodInfo> inputMethodInfos,
+            boolean hasHardKeyboard, @UserIdInt int userId) {
+        saveInputMethodSubtypeListForUserInternal(
+                fragment, resolver, inputMethodInfos, hasHardKeyboard, userId);
+    }
+
+    private static void saveInputMethodSubtypeListForUserInternal(PreferenceFragmentCompat fragment,
+            ContentResolver resolver, List<InputMethodInfo> inputMethodInfos,
+            boolean hasHardKeyboard, @UserIdInt int userId) {
+        String currentInputMethodId = Settings.Secure.getString(resolver,
+                Settings.Secure.DEFAULT_INPUT_METHOD);
+        final int selectedInputMethodSubtype = getInputMethodSubtypeSelected(resolver);
+        final HashMap<String, HashSet<String>> enabledIMEsAndSubtypesMap =
+                getEnabledInputMethodsAndSubtypeList(resolver);
+        final HashSet<String> disabledSystemIMEs = getDisabledSystemIMEs(resolver);
+
+        boolean needsToResetSelectedSubtype = false;
+        for (final InputMethodInfo imi : inputMethodInfos) {
+            final String imiId = imi.getId();
+            final Preference pref = fragment.findPreference(imiId);
+            if (pref == null) {
+                continue;
+            }
+            // In the choose input method screen or in the subtype enabler screen,
+            // <code>pref</code> is an instance of TwoStatePreference.
+            final boolean isImeChecked;
+            if (pref instanceof TwoStatePreference) {
+                isImeChecked = ((TwoStatePreference) pref).isChecked();
+            } else if (pref instanceof PrimarySwitchPreference) {
+                isImeChecked = ((PrimarySwitchPreference) pref).isChecked();
+            } else {
+                isImeChecked = enabledIMEsAndSubtypesMap.containsKey(imiId);
+            }
+            final boolean isCurrentInputMethod = imiId.equals(currentInputMethodId);
+            final boolean systemIme = imi.isSystem();
+            // Create context as given userId
+            final Context wrapperContext = userId == UserHandle.myUserId() ? fragment.getActivity()
+                    : fragment.getActivity().createContextAsUser(UserHandle.of(userId), 0);
+            if ((!hasHardKeyboard && InputMethodSettingValuesWrapper.getInstance(
+                    wrapperContext).isAlwaysCheckedIme(imi))
+                    || isImeChecked) {
+                if (!enabledIMEsAndSubtypesMap.containsKey(imiId)) {
+                    // imiId has just been enabled
+                    enabledIMEsAndSubtypesMap.put(imiId, new HashSet<>());
+                }
+                final HashSet<String> subtypesSet = enabledIMEsAndSubtypesMap.get(imiId);
+
+                boolean subtypePrefFound = false;
+                final int subtypeCount = imi.getSubtypeCount();
+                for (int i = 0; i < subtypeCount; ++i) {
+                    final InputMethodSubtype subtype = imi.getSubtypeAt(i);
+                    final String subtypeHashCodeStr = String.valueOf(subtype.hashCode());
+                    final TwoStatePreference subtypePref = (TwoStatePreference) fragment
+                            .findPreference(imiId + subtypeHashCodeStr);
+                    // In the Configure input method screen which does not have subtype preferences.
+                    if (subtypePref == null) {
+                        continue;
+                    }
+                    if (!subtypePrefFound) {
+                        // Once subtype preference is found, subtypeSet needs to be cleared.
+                        // Because of system change, hashCode value could have been changed.
+                        subtypesSet.clear();
+                        // If selected subtype preference is disabled, needs to reset.
+                        needsToResetSelectedSubtype = true;
+                        subtypePrefFound = true;
+                    }
+                    // Checking <code>subtypePref.isEnabled()</code> is insufficient to determine
+                    // whether the user manually enabled this subtype or not.  Implicitly-enabled
+                    // subtypes are also checked just as an indicator to users.  We also need to
+                    // check <code>subtypePref.isEnabled()</code> so that only manually enabled
+                    // subtypes can be saved here.
+                    if (subtypePref.isEnabled() && subtypePref.isChecked()) {
+                        subtypesSet.add(subtypeHashCodeStr);
+                        if (isCurrentInputMethod) {
+                            if (selectedInputMethodSubtype == subtype.hashCode()) {
+                                // Selected subtype is still enabled, there is no need to reset
+                                // selected subtype.
+                                needsToResetSelectedSubtype = false;
+                            }
+                        }
+                    } else {
+                        subtypesSet.remove(subtypeHashCodeStr);
+                    }
+                }
+            } else {
+                enabledIMEsAndSubtypesMap.remove(imiId);
+                if (isCurrentInputMethod) {
+                    // We are processing the current input method, but found that it's not enabled.
+                    // This means that the current input method has been uninstalled.
+                    // If currentInputMethod is already uninstalled, InputMethodManagerService will
+                    // find the applicable IME from the history and the system locale.
+                    if (DEBUG) {
+                        Log.d(TAG, "Current IME was uninstalled or disabled.");
+                    }
+                    currentInputMethodId = null;
+                }
+            }
+            // If it's a disabled system ime, add it to the disabled list so that it
+            // doesn't get enabled automatically on any changes to the package list
+            if (systemIme && hasHardKeyboard) {
+                if (disabledSystemIMEs.contains(imiId)) {
+                    if (isImeChecked) {
+                        disabledSystemIMEs.remove(imiId);
+                    }
+                } else {
+                    if (!isImeChecked) {
+                        disabledSystemIMEs.add(imiId);
+                    }
+                }
+            }
+        }
+
+        final String enabledIMEsAndSubtypesString = buildInputMethodsAndSubtypesString(
+                enabledIMEsAndSubtypesMap);
+        final String disabledSystemIMEsString = buildInputMethodsString(disabledSystemIMEs);
+        if (DEBUG) {
+            Log.d(TAG, "--- Save enabled inputmethod settings. :" + enabledIMEsAndSubtypesString);
+            Log.d(TAG, "--- Save disabled system inputmethod settings. :"
+                    + disabledSystemIMEsString);
+            Log.d(TAG, "--- Save default inputmethod settings. :" + currentInputMethodId);
+            Log.d(TAG, "--- Needs to reset the selected subtype :" + needsToResetSelectedSubtype);
+            Log.d(TAG, "--- Subtype is selected :" + isInputMethodSubtypeSelected(resolver));
+        }
+
+        // Redefines SelectedSubtype when all subtypes are unchecked or there is no subtype
+        // selected. And if the selected subtype of the current input method was disabled,
+        // We should reset the selected input method's subtype.
+        if (needsToResetSelectedSubtype || !isInputMethodSubtypeSelected(resolver)) {
+            if (DEBUG) {
+                Log.d(TAG, "--- Reset inputmethod subtype because it's not defined.");
+            }
+            putSelectedInputMethodSubtype(resolver, NOT_A_SUBTYPE_ID);
+        }
+
+        Settings.Secure.putString(resolver,
+                Settings.Secure.ENABLED_INPUT_METHODS, enabledIMEsAndSubtypesString);
+        if (disabledSystemIMEsString.length() > 0) {
+            Settings.Secure.putString(resolver, Settings.Secure.DISABLED_SYSTEM_INPUT_METHODS,
+                    disabledSystemIMEsString);
+        }
+        // If the current input method is unset, InputMethodManagerService will find the applicable
+        // IME from the history and the system locale.
+        Settings.Secure.putString(resolver, Settings.Secure.DEFAULT_INPUT_METHOD,
+                currentInputMethodId != null ? currentInputMethodId : "");
+    }
+
+    public static void loadInputMethodSubtypeList(final PreferenceFragmentCompat context,
+            final ContentResolver resolver, final List<InputMethodInfo> inputMethodInfos,
+            final Map<String, List<Preference>> inputMethodPrefsMap) {
+        final HashMap<String, HashSet<String>> enabledSubtypes =
+                getEnabledInputMethodsAndSubtypeList(resolver);
+
+        for (final InputMethodInfo imi : inputMethodInfos) {
+            final String imiId = imi.getId();
+            final Preference pref = context.findPreference(imiId);
+            if (pref instanceof TwoStatePreference) {
+                final TwoStatePreference subtypePref = (TwoStatePreference) pref;
+                final boolean isEnabled = enabledSubtypes.containsKey(imiId);
+                subtypePref.setChecked(isEnabled);
+                if (inputMethodPrefsMap != null) {
+                    for (final Preference childPref: inputMethodPrefsMap.get(imiId)) {
+                        childPref.setEnabled(isEnabled);
+                    }
+                }
+                setSubtypesPreferenceEnabled(context, inputMethodInfos, imiId, isEnabled);
+            }
+        }
+        updateSubtypesPreferenceChecked(context, inputMethodInfos, enabledSubtypes);
+    }
+
+    private static void setSubtypesPreferenceEnabled(final PreferenceFragmentCompat context,
+            final List<InputMethodInfo> inputMethodProperties, final String id,
+            final boolean enabled) {
+        final PreferenceScreen preferenceScreen = context.getPreferenceScreen();
+        for (final InputMethodInfo imi : inputMethodProperties) {
+            if (id.equals(imi.getId())) {
+                final int subtypeCount = imi.getSubtypeCount();
+                for (int i = 0; i < subtypeCount; ++i) {
+                    final InputMethodSubtype subtype = imi.getSubtypeAt(i);
+                    final TwoStatePreference pref = (TwoStatePreference) preferenceScreen
+                            .findPreference(id + subtype.hashCode());
+                    if (pref != null) {
+                        pref.setEnabled(enabled);
+                    }
+                }
+            }
+        }
+    }
+
+    private static void updateSubtypesPreferenceChecked(final PreferenceFragmentCompat context,
+            final List<InputMethodInfo> inputMethodProperties,
+            final HashMap<String, HashSet<String>> enabledSubtypes) {
+        final PreferenceScreen preferenceScreen = context.getPreferenceScreen();
+        for (final InputMethodInfo imi : inputMethodProperties) {
+            final String id = imi.getId();
+            if (!enabledSubtypes.containsKey(id)) {
+                // There is no need to enable/disable subtypes of disabled IMEs.
+                continue;
+            }
+            final HashSet<String> enabledSubtypesSet = enabledSubtypes.get(id);
+            final int subtypeCount = imi.getSubtypeCount();
+            for (int i = 0; i < subtypeCount; ++i) {
+                final InputMethodSubtype subtype = imi.getSubtypeAt(i);
+                final String hashCode = String.valueOf(subtype.hashCode());
+                if (DEBUG) {
+                    Log.d(TAG, "--- Set checked state: " + "id" + ", " + hashCode + ", "
+                            + enabledSubtypesSet.contains(hashCode));
+                }
+                final TwoStatePreference pref = (TwoStatePreference) preferenceScreen
+                        .findPreference(id + hashCode);
+                if (pref != null) {
+                    pref.setChecked(enabledSubtypesSet.contains(hashCode));
+                }
+            }
+        }
+    }
+
+    public static void removeUnnecessaryNonPersistentPreference(final Preference pref) {
+        final String key = pref.getKey();
+        if (pref.isPersistent() || key == null) {
+            return;
+        }
+        final SharedPreferences prefs = pref.getSharedPreferences();
+        if (prefs != null && prefs.contains(key)) {
+            prefs.edit().remove(key).apply();
+        }
+    }
+
+    @NonNull
+    public static String getSubtypeLocaleNameAsSentence(@Nullable InputMethodSubtype subtype,
+            @NonNull final Context context, @NonNull final InputMethodInfo inputMethodInfo) {
+        if (subtype == null) {
+            return "";
+        }
+        final Locale locale = getDisplayLocale(context);
+        final CharSequence subtypeName = subtype.getDisplayName(context,
+                inputMethodInfo.getPackageName(), inputMethodInfo.getServiceInfo()
+                        .applicationInfo);
+        return LocaleHelper.toSentenceCase(subtypeName.toString(), locale);
+    }
+
+    @NonNull
+    public static String getSubtypeLocaleNameListAsSentence(
+            @NonNull final List<InputMethodSubtype> subtypes, @NonNull final Context context,
+            @NonNull final InputMethodInfo inputMethodInfo) {
+        if (subtypes.isEmpty()) {
+            return "";
+        }
+        final Locale locale = getDisplayLocale(context);
+        final int subtypeCount = subtypes.size();
+        final CharSequence[] subtypeNames = new CharSequence[subtypeCount];
+        for (int i = 0; i < subtypeCount; i++) {
+            subtypeNames[i] = subtypes.get(i).getDisplayName(context,
+                    inputMethodInfo.getPackageName(), inputMethodInfo.getServiceInfo()
+                            .applicationInfo);
+        }
+        return LocaleHelper.toSentenceCase(
+                ListFormatter.getInstance(locale).format((Object[]) subtypeNames), locale);
+    }
+
+    @NonNull
+    private static Locale getDisplayLocale(@Nullable final Context context) {
+        if (context == null) {
+            return Locale.getDefault();
+        }
+        if (context.getResources() == null) {
+            return Locale.getDefault();
+        }
+        final Configuration configuration = context.getResources().getConfiguration();
+        if (configuration == null) {
+            return Locale.getDefault();
+        }
+        final Locale configurationLocale = configuration.getLocales().get(0);
+        if (configurationLocale == null) {
+            return Locale.getDefault();
+        }
+        return configurationLocale;
+    }
+
+    public static boolean isValidSystemNonAuxAsciiCapableIme(InputMethodInfo imi) {
+        if (imi.isAuxiliaryIme() || !imi.isSystem()) {
+            return false;
+        }
+        final int subtypeCount = imi.getSubtypeCount();
+        for (int i = 0; i < subtypeCount; ++i) {
+            final InputMethodSubtype subtype = imi.getSubtypeAt(i);
+            if (SUBTYPE_MODE_KEYBOARD.equalsIgnoreCase(subtype.getMode())
+                    && subtype.isAsciiCapable()) {
+                return true;
+            }
+        }
+        return false;
+    }
+}

SettingsLib/src/com/android/settingslib/inputmethod/InputMethodPreference.java

@@ -0,0 +1,326 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settingslib.inputmethod;
+
+import static com.android.settingslib.RestrictedLockUtils.EnforcedAdmin;
+
+import android.annotation.UserIdInt;
+import android.app.AlertDialog;
+import android.content.ActivityNotFoundException;
+import android.content.Context;
+import android.content.Intent;
+import android.content.res.Configuration;
+import android.os.UserHandle;
+import android.text.TextUtils;
+import android.util.Log;
+import android.view.ViewGroup;
+import android.view.inputmethod.InputMethodInfo;
+import android.view.inputmethod.InputMethodManager;
+import android.view.inputmethod.InputMethodSubtype;
+import android.widget.CompoundButton;
+import android.widget.ImageView;
+import android.widget.Toast;
+
+import androidx.preference.Preference;
+import androidx.preference.Preference.OnPreferenceChangeListener;
+import androidx.preference.Preference.OnPreferenceClickListener;
+import androidx.preference.PreferenceViewHolder;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.settingslib.PrimarySwitchPreference;
+import com.android.settingslib.R;
+import com.android.settingslib.RestrictedLockUtilsInternal;
+
+import java.text.Collator;
+import java.util.List;
+
+/**
+ * Input method preference.
+ *
+ * This preference represents an IME. It is used for two purposes. 1) Using a switch to enable or
+ * disable the IME 2) Invoking the setting activity of the IME.
+ */
+public class InputMethodPreference extends PrimarySwitchPreference
+        implements OnPreferenceClickListener, OnPreferenceChangeListener {
+    private static final String TAG = InputMethodPreference.class.getSimpleName();
+
+    public interface OnSavePreferenceListener {
+        /**
+         * Called when this preference needs to be saved its state.
+         *
+         * Note that this preference is non-persistent and needs explicitly to be saved its state.
+         * Because changing one IME state may change other IMEs' state, this is a place to update
+         * other IMEs' state as well.
+         *
+         * @param pref This preference.
+         */
+        void onSaveInputMethodPreference(InputMethodPreference pref);
+    }
+
+    private final InputMethodInfo mImi;
+    private final boolean mHasPriorityInSorting;
+    private final OnSavePreferenceListener mOnSaveListener;
+    private final InputMethodSettingValuesWrapper mInputMethodSettingValues;
+    private final boolean mIsAllowedByOrganization;
+    @UserIdInt
+    private final int mUserId;
+
+    private AlertDialog mDialog = null;
+
+    /**
+     * A preference entry of an input method.
+     *
+     * @param prefContext The Context this preference is associated with.
+     * @param imi The {@link InputMethodInfo} of this preference.
+     * @param isAllowedByOrganization false if the IME has been disabled by a device or profile
+     *     owner.
+     * @param onSaveListener The listener called when this preference has been changed and needs
+     *     to save the state to shared preference.
+     * @param userId The userId to specify the corresponding user for this preference.
+     */
+    public InputMethodPreference(final Context prefContext, final InputMethodInfo imi,
+            final boolean isAllowedByOrganization, final OnSavePreferenceListener onSaveListener,
+            final @UserIdInt int userId) {
+        this(prefContext, imi, imi.loadLabel(prefContext.getPackageManager()),
+                isAllowedByOrganization, onSaveListener, userId);
+    }
+
+    @VisibleForTesting
+    InputMethodPreference(final Context prefContext, final InputMethodInfo imi,
+            final CharSequence title, final boolean isAllowedByOrganization,
+            final OnSavePreferenceListener onSaveListener, final @UserIdInt int userId) {
+        super(prefContext);
+        setPersistent(false);
+        mImi = imi;
+        mIsAllowedByOrganization = isAllowedByOrganization;
+        mOnSaveListener = onSaveListener;
+        setKey(imi.getId());
+        setTitle(title);
+        final String settingsActivity = imi.getSettingsActivity();
+        if (TextUtils.isEmpty(settingsActivity)) {
+            setIntent(null);
+        } else {
+            // Set an intent to invoke settings activity of an input method.
+            final Intent intent = new Intent(Intent.ACTION_MAIN);
+            intent.setClassName(imi.getPackageName(), settingsActivity);
+            setIntent(intent);
+        }
+        // Handle the context by given userId because {@link InputMethodSettingValuesWrapper} is
+        // per-user instance.
+        final Context userAwareContext = userId == UserHandle.myUserId() ? prefContext :
+                getContext().createContextAsUser(UserHandle.of(userId), 0);
+        mInputMethodSettingValues = InputMethodSettingValuesWrapper.getInstance(userAwareContext);
+        mUserId = userId;
+        mHasPriorityInSorting = imi.isSystem()
+                && InputMethodAndSubtypeUtil.isValidNonAuxAsciiCapableIme(imi);
+        setOnPreferenceClickListener(this);
+        setOnPreferenceChangeListener(this);
+    }
+
+    public InputMethodInfo getInputMethodInfo() {
+        return mImi;
+    }
+
+    @Override
+    public void onBindViewHolder(PreferenceViewHolder holder) {
+        super.onBindViewHolder(holder);
+        final CompoundButton switchWidget = getSwitch();
+        if (switchWidget != null) {
+            // Avoid default behavior in {@link PrimarySwitchPreference#onBindViewHolder}.
+            switchWidget.setOnClickListener(v -> {
+                if (!switchWidget.isEnabled()) {
+                    return;
+                }
+                final boolean newValue = !isChecked();
+                // Keep switch to previous state because we have to show the dialog first.
+                switchWidget.setChecked(isChecked());
+                callChangeListener(newValue);
+            });
+        }
+        final ImageView icon = holder.itemView.findViewById(android.R.id.icon);
+        final int iconSize = getContext().getResources().getDimensionPixelSize(
+                com.android.settingslib.widget.theme.R.dimen.secondary_app_icon_size);
+        if (icon != null && iconSize > 0) {
+            ViewGroup.LayoutParams params = icon.getLayoutParams();
+            params.height = iconSize;
+            params.width = iconSize;
+            icon.setLayoutParams(params);
+        }
+    }
+
+    @Override
+    public boolean onPreferenceChange(final Preference preference, final Object newValue) {
+        // Always returns false to prevent default behavior.
+        // See {@link TwoStatePreference#onClick()}.
+        if (isChecked()) {
+            // Disable this IME.
+            setCheckedInternal(false);
+            return false;
+        }
+        if (mImi.isSystem()) {
+            // Enable a system IME. No need to show a security warning dialog,
+            // but we might need to prompt if it's not Direct Boot aware.
+            // TV doesn't doesn't need to worry about this, but other platforms should show
+            // a warning.
+            if (mImi.getServiceInfo().directBootAware || isTv()) {
+                setCheckedInternal(true);
+            } else if (!isTv()){
+                showDirectBootWarnDialog();
+            }
+        } else {
+            // Once security is confirmed, we might prompt if the IME isn't
+            // Direct Boot aware.
+            showSecurityWarnDialog();
+        }
+        return false;
+    }
+
+    @Override
+    public boolean onPreferenceClick(final Preference preference) {
+        // Always returns true to prevent invoking an intent without catching exceptions.
+        // See {@link Preference#performClick(PreferenceScreen)}/
+        final Context context = getContext();
+        try {
+            final Intent intent = getIntent();
+            if (intent != null) {
+                // Invoke a settings activity of an input method.
+                context.startActivityAsUser(intent, UserHandle.of(mUserId));
+            }
+        } catch (final ActivityNotFoundException e) {
+            Log.d(TAG, "IME's Settings Activity Not Found", e);
+            final String message = context.getString(
+                    R.string.failed_to_open_app_settings_toast,
+                    mImi.loadLabel(context.getPackageManager()));
+            Toast.makeText(context, message, Toast.LENGTH_LONG).show();
+        }
+        return true;
+    }
+
+    public void updatePreferenceViews() {
+        final boolean isAlwaysChecked = mInputMethodSettingValues.isAlwaysCheckedIme(mImi);
+        // When this preference has a switch and an input method should be always enabled,
+        // this preference should be disabled to prevent accidentally disabling an input method.
+        // This preference should also be disabled in case the admin does not allow this input
+        // method.
+        if (isAlwaysChecked) {
+            setDisabledByAdmin(null);
+            setSwitchEnabled(false);
+        } else if (!mIsAllowedByOrganization) {
+            EnforcedAdmin admin =
+                    RestrictedLockUtilsInternal.checkIfInputMethodDisallowed(
+                            getContext(), mImi.getPackageName(), mUserId);
+            setDisabledByAdmin(admin);
+        } else {
+            setEnabled(true);
+            setSwitchEnabled(true);
+        }
+        setChecked(mInputMethodSettingValues.isEnabledImi(mImi));
+        if (!isDisabledByAdmin()) {
+            setSummary(getSummaryString());
+        }
+    }
+
+    private InputMethodManager getInputMethodManager() {
+        return (InputMethodManager)getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
+    }
+
+    private String getSummaryString() {
+        final InputMethodManager imm = getInputMethodManager();
+        final List<InputMethodSubtype> subtypes = imm.getEnabledInputMethodSubtypeList(mImi, true);
+        return InputMethodAndSubtypeUtil.getSubtypeLocaleNameListAsSentence(
+                subtypes, getContext(), mImi);
+    }
+
+    private void setCheckedInternal(boolean checked) {
+        super.setChecked(checked);
+        mOnSaveListener.onSaveInputMethodPreference(InputMethodPreference.this);
+        notifyChanged();
+    }
+
+    private void showSecurityWarnDialog() {
+        if (mDialog != null && mDialog.isShowing()) {
+            mDialog.dismiss();
+        }
+        final Context context = getContext();
+        final AlertDialog.Builder builder = new AlertDialog.Builder(context);
+        builder.setCancelable(true /* cancelable */);
+        builder.setTitle(android.R.string.dialog_alert_title);
+        final CharSequence label = mImi.getServiceInfo().applicationInfo.loadLabel(
+                context.getPackageManager());
+        builder.setMessage(context.getString(R.string.ime_security_warning, label));
+        builder.setPositiveButton(android.R.string.ok, (dialog, which) -> {
+            // The user confirmed to enable a 3rd party IME, but we might
+            // need to prompt if it's not Direct Boot aware.
+            // TV doesn't doesn't need to worry about this, but other platforms should show
+            // a warning.
+            if (mImi.getServiceInfo().directBootAware || isTv()) {
+                setCheckedInternal(true);
+            } else {
+                showDirectBootWarnDialog();
+            }
+        });
+        builder.setNegativeButton(android.R.string.cancel, (dialog, which) -> {
+            // The user canceled to enable a 3rd party IME.
+            setCheckedInternal(false);
+        });
+        builder.setOnCancelListener((dialog) -> {
+            // The user canceled to enable a 3rd party IME.
+            setCheckedInternal(false);
+        });
+        mDialog = builder.create();
+        mDialog.show();
+    }
+
+    private boolean isTv() {
+        return (getContext().getResources().getConfiguration().uiMode
+                & Configuration.UI_MODE_TYPE_MASK) == Configuration.UI_MODE_TYPE_TELEVISION;
+    }
+
+    private void showDirectBootWarnDialog() {
+        if (mDialog != null && mDialog.isShowing()) {
+            mDialog.dismiss();
+        }
+        final Context context = getContext();
+        final AlertDialog.Builder builder = new AlertDialog.Builder(context);
+        builder.setCancelable(true /* cancelable */);
+        builder.setMessage(context.getText(R.string.direct_boot_unaware_dialog_message));
+        builder.setPositiveButton(android.R.string.ok, (dialog, which) -> setCheckedInternal(true));
+        builder.setNegativeButton(android.R.string.cancel,
+                (dialog, which) -> setCheckedInternal(false));
+        mDialog = builder.create();
+        mDialog.show();
+    }
+
+    public int compareTo(final InputMethodPreference rhs, final Collator collator) {
+        if (this == rhs) {
+            return 0;
+        }
+        if (mHasPriorityInSorting != rhs.mHasPriorityInSorting) {
+            // Prefer always checked system IMEs
+            return mHasPriorityInSorting ? -1 : 1;
+        }
+        final CharSequence title = getTitle();
+        final CharSequence rhsTitle = rhs.getTitle();
+        final boolean emptyTitle = TextUtils.isEmpty(title);
+        final boolean rhsEmptyTitle = TextUtils.isEmpty(rhsTitle);
+        if (!emptyTitle && !rhsEmptyTitle) {
+            return collator.compare(title.toString(), rhsTitle.toString());
+        }
+        // For historical reasons, an empty text needs to be put at the first.
+        return (emptyTitle ? -1 : 0) - (rhsEmptyTitle ? -1 : 0);
+    }
+}

SettingsLib/src/com/android/settingslib/inputmethod/InputMethodSettingValuesWrapper.java

@@ -0,0 +1,164 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package com.android.settingslib.inputmethod;
+
+import android.annotation.AnyThread;
+import android.annotation.UiThread;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.util.Log;
+import android.util.SparseArray;
+import android.view.inputmethod.InputMethodInfo;
+import android.view.inputmethod.InputMethodManager;
+
+import androidx.annotation.NonNull;
+
+import com.android.internal.annotations.GuardedBy;
+import com.android.internal.inputmethod.DirectBootAwareness;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+
+/**
+ * This class is a wrapper for {@link InputMethodManager} and
+ * {@link android.provider.Settings.Secure#ENABLED_INPUT_METHODS}. You need to refresh internal
+ * states manually on some events when "InputMethodInfo"s and "InputMethodSubtype"s can be changed.
+ *
+ * <p>TODO: Consolidate this with {@link InputMethodAndSubtypeUtil}.</p>
+ */
+@UiThread
+public class InputMethodSettingValuesWrapper {
+    private static final String TAG = InputMethodSettingValuesWrapper.class.getSimpleName();
+
+    private static final Object sInstanceMapLock = new Object();
+    /**
+     * Manages mapping between user ID and corresponding singleton
+     * {@link InputMethodSettingValuesWrapper} object.
+     */
+    @GuardedBy("sInstanceMapLock")
+    private static SparseArray<InputMethodSettingValuesWrapper> sInstanceMap = new SparseArray<>();
+    private final ArrayList<InputMethodInfo> mMethodList = new ArrayList<>();
+    private final ContentResolver mContentResolver;
+    private final InputMethodManager mImm;
+
+    @AnyThread
+    @NonNull
+    public static InputMethodSettingValuesWrapper getInstance(@NonNull Context context) {
+        final int requestUserId = context.getUserId();
+        InputMethodSettingValuesWrapper valuesWrapper;
+        // First time to create the wrapper.
+        synchronized (sInstanceMapLock) {
+            if (sInstanceMap.size() == 0) {
+                valuesWrapper = new InputMethodSettingValuesWrapper(context);
+                sInstanceMap.put(requestUserId, valuesWrapper);
+                return valuesWrapper;
+            }
+            // We have same user context as request.
+            if (sInstanceMap.indexOfKey(requestUserId) >= 0) {
+                return sInstanceMap.get(requestUserId);
+            }
+            // Request by a new user context.
+            valuesWrapper = new InputMethodSettingValuesWrapper(context);
+            sInstanceMap.put(context.getUserId(), valuesWrapper);
+        }
+
+        return valuesWrapper;
+    }
+
+    // Ensure singleton
+    private InputMethodSettingValuesWrapper(Context context) {
+        mContentResolver = context.getContentResolver();
+        mImm = context.getSystemService(InputMethodManager.class);
+        refreshAllInputMethodAndSubtypes();
+    }
+
+    public void refreshAllInputMethodAndSubtypes() {
+        mMethodList.clear();
+        List<InputMethodInfo> imis = mImm.getInputMethodListAsUser(
+                mContentResolver.getUserId(), DirectBootAwareness.ANY);
+        for (int i = 0; i < imis.size(); ++i) {
+            InputMethodInfo imi = imis.get(i);
+            if (!imi.isVirtualDeviceOnly()) {
+                mMethodList.add(imi);
+            }
+        }
+    }
+
+    public List<InputMethodInfo> getInputMethodList() {
+        return new ArrayList<>(mMethodList);
+    }
+
+    public boolean isAlwaysCheckedIme(InputMethodInfo imi) {
+        final boolean isEnabled = isEnabledImi(imi);
+        if (getEnabledInputMethodList().size() <= 1 && isEnabled) {
+            return true;
+        }
+
+        final int enabledValidNonAuxAsciiCapableImeCount =
+                getEnabledValidNonAuxAsciiCapableImeCount();
+
+        return enabledValidNonAuxAsciiCapableImeCount <= 1
+                && !(enabledValidNonAuxAsciiCapableImeCount == 1 && !isEnabled)
+                && imi.isSystem()
+                && InputMethodAndSubtypeUtil.isValidNonAuxAsciiCapableIme(imi);
+    }
+
+    private int getEnabledValidNonAuxAsciiCapableImeCount() {
+        int count = 0;
+        final List<InputMethodInfo> enabledImis = getEnabledInputMethodList();
+        for (final InputMethodInfo imi : enabledImis) {
+            if (InputMethodAndSubtypeUtil.isValidNonAuxAsciiCapableIme(imi)) {
+                ++count;
+            }
+        }
+        if (count == 0) {
+            Log.w(TAG, "No \"enabledValidNonAuxAsciiCapableIme\"s found.");
+        }
+        return count;
+    }
+
+    public boolean isEnabledImi(InputMethodInfo imi) {
+        final List<InputMethodInfo> enabledImis = getEnabledInputMethodList();
+        for (final InputMethodInfo tempImi : enabledImis) {
+            if (tempImi.getId().equals(imi.getId())) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Returns the list of the enabled {@link InputMethodInfo} determined by
+     * {@link android.provider.Settings.Secure#ENABLED_INPUT_METHODS} rather than just returning
+     * {@link InputMethodManager#getEnabledInputMethodList()}.
+     *
+     * @return the list of the enabled {@link InputMethodInfo}
+     */
+    private ArrayList<InputMethodInfo> getEnabledInputMethodList() {
+        final HashMap<String, HashSet<String>> enabledInputMethodsAndSubtypes =
+                InputMethodAndSubtypeUtil.getEnabledInputMethodsAndSubtypeList(mContentResolver);
+        final ArrayList<InputMethodInfo> result = new ArrayList<>();
+        for (InputMethodInfo imi : mMethodList) {
+            if (enabledInputMethodsAndSubtypes.keySet().contains(imi.getId())) {
+                result.add(imi);
+            }
+        }
+        return result;
+    }
+}

SettingsLib/src/com/android/settingslib/inputmethod/InputMethodSubtypePreference.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package com.android.settingslib.inputmethod;
+
+import android.content.Context;
+import android.text.TextUtils;
+import android.view.inputmethod.InputMethodInfo;
+import android.view.inputmethod.InputMethodSubtype;
+
+import androidx.preference.Preference;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.text.Collator;
+import java.util.Locale;
+
+/**
+ * Input method subtype preference.
+ *
+ * This preference represents a subtype of an IME. It is used to enable or disable the subtype.
+ */
+public class InputMethodSubtypePreference extends SwitchWithNoTextPreference {
+    private final boolean mIsSystemLocale;
+    private final boolean mIsSystemLanguage;
+
+    public InputMethodSubtypePreference(final Context context, final InputMethodSubtype subtype,
+            final InputMethodInfo imi) {
+        this(context,
+                imi.getId() + subtype.hashCode(),
+                InputMethodAndSubtypeUtil.getSubtypeLocaleNameAsSentence(subtype, context, imi),
+                subtype.getLocaleObject(),
+                context.getResources().getConfiguration().locale);
+    }
+
+    @VisibleForTesting
+    InputMethodSubtypePreference(
+            final Context context,
+            final String prefKey,
+            final CharSequence title,
+            final Locale subtypeLocale,
+            final Locale systemLocale) {
+        super(context);
+        setPersistent(false);
+        setKey(prefKey);
+        setTitle(title);
+        if (subtypeLocale == null) {
+            mIsSystemLocale = false;
+            mIsSystemLanguage = false;
+        } else {
+            mIsSystemLocale = subtypeLocale.equals(systemLocale);
+            mIsSystemLanguage = mIsSystemLocale
+                    || TextUtils.equals(subtypeLocale.getLanguage(), systemLocale.getLanguage());
+        }
+    }
+
+    public int compareTo(final Preference rhs, final Collator collator) {
+        if (this == rhs) {
+            return 0;
+        }
+        if (rhs instanceof InputMethodSubtypePreference) {
+            final InputMethodSubtypePreference rhsPref = (InputMethodSubtypePreference) rhs;
+            if (mIsSystemLocale && !rhsPref.mIsSystemLocale) {
+                return -1;
+            }
+            if (!mIsSystemLocale && rhsPref.mIsSystemLocale) {
+                return 1;
+            }
+            if (mIsSystemLanguage && !rhsPref.mIsSystemLanguage) {
+                return -1;
+            }
+            if (!mIsSystemLanguage && rhsPref.mIsSystemLanguage) {
+                return 1;
+            }
+            final CharSequence title = getTitle();
+            final CharSequence rhsTitle = rhs.getTitle();
+            final boolean emptyTitle = TextUtils.isEmpty(title);
+            final boolean rhsEmptyTitle = TextUtils.isEmpty(rhsTitle);
+            if (!emptyTitle && !rhsEmptyTitle) {
+                return collator.compare(title.toString(), rhsTitle.toString());
+            }
+            // For historical reasons, an empty text needs to be put at the first.
+            return (emptyTitle ? -1 : 0) - (rhsEmptyTitle ? -1 : 0);
+        }
+        return super.compareTo(rhs);
+    }
+}

SettingsLib/src/com/android/settingslib/inputmethod/OWNERS

@@ -0,0 +1,3 @@
+# Bug component: 34867
+
+include platform/frameworks/base:/services/core/java/com/android/server/inputmethod/OWNERS

SettingsLib/src/com/android/settingslib/inputmethod/SwitchWithNoTextPreference.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package com.android.settingslib.inputmethod;
+
+import android.content.Context;
+
+import androidx.preference.SwitchPreference;
+
+public class SwitchWithNoTextPreference extends SwitchPreference {
+    private static final String EMPTY_TEXT = "";
+
+    public SwitchWithNoTextPreference(final Context context) {
+        super(context);
+        setSwitchTextOn(EMPTY_TEXT);
+        setSwitchTextOff(EMPTY_TEXT);
+    }
+}