Add support for adding plugin views behind the main view on Android

Doesn't change the default behavior, but allows plugins to add their
view behind the main view, which gives more control over what happens
with inputs and can be useful along with transparent rendering.

2 files changed, 19 insertions, 1 deletions

diff --git a/platform/android/java/lib/src/org/godotengine/godot/Godot.java b/platform/android/java/lib/src/org/godotengine/godot/Godot.java
index 896b169953..70bc73b9ad 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/Godot.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/Godot.java
@@ -295,7 +295,11 @@ public class Godot extends Fragment implements SensorEventListener, IDownloaderC
 		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
 			View pluginView = plugin.onMainCreate(activity);
 			if (pluginView != null) {
-				containerLayout.addView(pluginView);
+				if (plugin.shouldBeOnTop()) {
+					containerLayout.addView(pluginView);
+				} else {
+					containerLayout.addView(pluginView, 0);
+				}
 			}
 		}
 	}
diff --git a/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPlugin.java b/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPlugin.java
index 2dc8359615..4536c21ed3 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPlugin.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPlugin.java
@@ -191,6 +191,9 @@ public abstract class GodotPlugin {
 	 * The plugin can return a non-null {@link View} layout in order to add it to the Godot view
 	 * hierarchy.
 	 *
+	 * Use shouldBeOnTop() to set whether the plugin's {@link View} should be added on top or behind
+	 * the main Godot view.
+	 *
 	 * @see Activity#onCreate(Bundle)
 	 * @return the plugin's view to be included; null if no views should be included.
 	 */
@@ -311,6 +314,17 @@ public abstract class GodotPlugin {
 	}
 
 	/**
+	 * Returns whether the plugin's {@link View} returned in onMainCreate() should be placed on
+	 * top of the main Godot view.
+	 *
+	 * Returning false causes the plugin's {@link View} to be placed behind, which can be useful
+	 * when used with transparency in order to let the Godot view handle inputs.
+	 */
+	public boolean shouldBeOnTop() {
+		return true;
+	}
+
+	/**
 	 * Runs the specified action on the UI thread. If the current thread is the UI
 	 * thread, then the action is executed immediately. If the current thread is
 	 * not the UI thread, the action is posted to the event queue of the UI thread.