Render theme from Android content providers

docs/Changelog.md

@@ -2,6 +2,7 @@
 
 ## New since 0.14.0
 
+- Render theme from Android content providers [#783](https://github.com/mapsforge/vtm/pull/783)
 - Many other minor improvements and bug fixes
 - [Solved issues](https://github.com/mapsforge/vtm/issues?q=is%3Aclosed+milestone%3A0.15.0)
 
@@ -229,6 +230,8 @@
 - libGDX layer gestures [#151](https://github.com/mapsforge/vtm/issues/151)
 - Render theme area tessellation option [#37](https://github.com/mapsforge/vtm/issues/37)
 - Render theme resources optional location prefixes [#66](https://github.com/mapsforge/vtm/issues/66)
+- Render theme from input stream [#161](https://github.com/mapsforge/vtm/issues/161)
+- Render theme from Android assets [#162](https://github.com/mapsforge/vtm/issues/162)
 - Graphics API platform enhancements [#92](https://github.com/mapsforge/vtm/issues/92)
 - GeoPoint & BoundingBox improvements [#201](https://github.com/mapsforge/vtm/issues/201) [#200](https://github.com/mapsforge/vtm/issues/200)
 - vtm-jts module [#53](https://github.com/mapsforge/vtm/issues/53)

vtm-android/src/org/oscim/android/theme/ContentRenderTheme.java

@@ -0,0 +1,109 @@
+/*
+ * Copyright 2020 devemux86
+ *
+ * This program is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.oscim.android.theme;
+
+import android.content.ContentResolver;
+import android.net.Uri;
+import org.oscim.theme.IRenderTheme.ThemeException;
+import org.oscim.theme.ThemeFile;
+import org.oscim.theme.ThemeUtils;
+import org.oscim.theme.XmlRenderThemeMenuCallback;
+import org.oscim.utils.Utils;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * An ContentRenderTheme allows for customizing the rendering style of the map
+ * via an XML from the Android content providers.
+ */
+public class ContentRenderTheme implements ThemeFile {
+    private static final long serialVersionUID = 1L;
+
+    private final ContentResolver mContentResolver;
+    private XmlRenderThemeMenuCallback mMenuCallback;
+    private final String mRelativePathPrefix;
+    private final Uri mUri;
+
+    /**
+     * @param contentResolver    the Android content resolver.
+     * @param relativePathPrefix the prefix for all relative resource paths.
+     * @param uri                the XML render theme URI.
+     * @throws ThemeException if an error occurs while reading the render theme XML.
+     */
+    public ContentRenderTheme(ContentResolver contentResolver, String relativePathPrefix, Uri uri) throws ThemeException {
+        this(contentResolver, relativePathPrefix, uri, null);
+    }
+
+    /**
+     * @param contentResolver    the Android content resolver.
+     * @param relativePathPrefix the prefix for all relative resource paths.
+     * @param uri                the XML render theme URI.
+     * @param menuCallback       the interface callback to create a settings menu on the fly.
+     * @throws ThemeException if an error occurs while reading the render theme XML.
+     */
+    public ContentRenderTheme(ContentResolver contentResolver, String relativePathPrefix, Uri uri, XmlRenderThemeMenuCallback menuCallback) throws ThemeException {
+        mContentResolver = contentResolver;
+        mRelativePathPrefix = relativePathPrefix;
+        mUri = uri;
+        mMenuCallback = menuCallback;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        } else if (!(obj instanceof ContentRenderTheme)) {
+            return false;
+        }
+        ContentRenderTheme other = (ContentRenderTheme) obj;
+        if (getRenderThemeAsStream() != other.getRenderThemeAsStream()) {
+            return false;
+        }
+        if (!Utils.equals(mRelativePathPrefix, other.mRelativePathPrefix)) {
+            return false;
+        }
+        return true;
+    }
+
+    @Override
+    public XmlRenderThemeMenuCallback getMenuCallback() {
+        return mMenuCallback;
+    }
+
+    @Override
+    public String getRelativePathPrefix() {
+        return mRelativePathPrefix;
+    }
+
+    @Override
+    public InputStream getRenderThemeAsStream() throws ThemeException {
+        try {
+            return mContentResolver.openInputStream(mUri);
+        } catch (IOException e) {
+            throw new ThemeException(e.getMessage());
+        }
+    }
+
+    @Override
+    public boolean isMapsforgeTheme() {
+        return ThemeUtils.isMapsforgeTheme(this);
+    }
+
+    @Override
+    public void setMenuCallback(XmlRenderThemeMenuCallback menuCallback) {
+        mMenuCallback = menuCallback;
+    }
+}