[android] Add bindings for onRemoveUnusedStyleImages API

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapChangeReceiver.java

@@ -33,6 +33,8 @@ class MapChangeReceiver implements NativeMapView.StateCallback {
   private final List<MapView.OnSourceChangedListener> onSourceChangedListenerList = new CopyOnWriteArrayList<>();
   private final List<MapView.OnStyleImageMissingListener> onStyleImageMissingListenerList
     = new CopyOnWriteArrayList<>();
+  private final List<MapView.OnCanRemoveUnusedStyleImageListener> onCanRemoveUnusedStyleImageListenerList
+    = new CopyOnWriteArrayList<>();
 
   @Override
   public void onCameraWillChange(boolean animated) {
@@ -230,6 +232,29 @@ class MapChangeReceiver implements NativeMapView.StateCallback {
     }
   }
 
+  @Override
+  public boolean onCanRemoveUnusedStyleImage(String imageId) {
+    if (onCanRemoveUnusedStyleImageListenerList.isEmpty()) {
+      return true;
+    }
+
+    try {
+      if (!onCanRemoveUnusedStyleImageListenerList.isEmpty()) {
+        boolean canRemove = true;
+        for (MapView.OnCanRemoveUnusedStyleImageListener listener : onCanRemoveUnusedStyleImageListenerList) {
+          canRemove &= listener.onCanRemoveUnusedStyleImage(imageId);
+        }
+
+        return canRemove;
+      }
+    } catch (Throwable err) {
+      Logger.e(TAG, "Exception in onCanRemoveUnusedStyleImage", err);
+      throw err;
+    }
+
+    return true;
+  }
+
   void addOnCameraWillChangeListener(MapView.OnCameraWillChangeListener listener) {
     onCameraWillChangeListenerList.add(listener);
   }
@@ -342,6 +367,14 @@ class MapChangeReceiver implements NativeMapView.StateCallback {
     onStyleImageMissingListenerList.remove(listener);
   }
 
+  void addOnCanRemoveUnusedStyleImageListener(MapView.OnCanRemoveUnusedStyleImageListener listener) {
+    onCanRemoveUnusedStyleImageListenerList.add(listener);
+  }
+
+  void removeOnCanRemoveUnusedStyleImageListener(MapView.OnCanRemoveUnusedStyleImageListener listener) {
+    onCanRemoveUnusedStyleImageListenerList.remove(listener);
+  }
+
   void clear() {
     onCameraWillChangeListenerList.clear();
     onCameraIsChangingListenerList.clear();
@@ -357,5 +390,6 @@ class MapChangeReceiver implements NativeMapView.StateCallback {
     onDidFinishLoadingStyleListenerList.clear();
     onSourceChangedListenerList.clear();
     onStyleImageMissingListenerList.clear();
+    onCanRemoveUnusedStyleImageListenerList.clear();
   }
 }

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapView.java

@@ -797,6 +797,33 @@ public class MapView extends FrameLayout implements NativeMapView.ViewCallback {
     mapChangeReceiver.removeOnStyleImageMissingListener(listener);
   }
 
+  /**
+   * Set a callback that's invoked when map needs to release unused image resources.
+   *
+   * A callback will be called only for unused images that were provided by the client via
+   * {@link OnStyleImageMissingListener#onStyleImageMissing(String)} listener interface.
+   *
+   * By default, platform will remove unused images from the style. By adding listener, default
+   * behavior can be overridden and client can control whether to release unused resources.
+   *
+   * @param listener The callback that's invoked when map needs to release unused image resources
+   */
+  public void addOnCanRemoveUnusedStyleImageListener(@NonNull OnCanRemoveUnusedStyleImageListener listener) {
+    mapChangeReceiver.addOnCanRemoveUnusedStyleImageListener(listener);
+  }
+
+  /**
+   * Removes a callback that's invoked when map needs to release unused image resources.
+   *
+   * When all listeners are removed, platform will fallback to default behavior, which is to remove
+   * unused images from the style.
+   *
+   * @param listener The callback that's invoked when map needs to release unused image resources
+   */
+  public void removeOnCanRemoveUnusedStyleImageListener(@NonNull OnCanRemoveUnusedStyleImageListener listener) {
+    mapChangeReceiver.removeOnCanRemoveUnusedStyleImageListener(listener);
+  }
+
   /**
    * Interface definition for a callback to be invoked when the camera will change.
    * <p>
@@ -994,6 +1021,22 @@ public class MapView extends FrameLayout implements NativeMapView.ViewCallback {
     void onStyleImageMissing(@NonNull String id);
   }
 
+  /**
+   * Interface definition for a callback to be invoked with an unused image identifier.
+   * <p>
+   * {@link MapView#addOnCanRemoveUnusedStyleImageListener(OnCanRemoveUnusedStyleImageListener)}
+   * </p>
+   */
+  public interface OnCanRemoveUnusedStyleImageListener {
+    /**
+     * Called when the map needs to release unused image resources.
+     *
+     * @param id of an image that is not used by the map and can be removed from the style.
+     * @return true if image can be removed, false otherwise.
+     */
+    boolean onCanRemoveUnusedStyleImage(@NonNull String id);
+  }
+
   /**
    * Sets a callback object which will be triggered when the {@link MapboxMap} instance is ready to be used.
    *

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/NativeMapView.java

@@ -1050,6 +1050,15 @@ final class NativeMapView implements NativeMap {
     }
   }
 
+  @Keep
+  private boolean onCanRemoveUnusedStyleImage(String imageId) {
+    if (stateCallback != null) {
+      return stateCallback.onCanRemoveUnusedStyleImage(imageId);
+    }
+
+    return true;
+  }
+
   @Keep
   protected void onSnapshotReady(@Nullable Bitmap mapContent) {
     if (checkState("OnSnapshotReady")) {
@@ -1463,5 +1472,7 @@ final class NativeMapView implements NativeMap {
     void onSourceChanged(String sourceId);
 
     void onStyleImageMissing(String imageId);
+
+    boolean onCanRemoveUnusedStyleImage(String imageId);
   }
 }