ViewTreeObserver: implement onGlobalLayout properly

src/api-impl/android/view/View.java

@@ -867,7 +867,7 @@ public class View implements Drawable.Callback {
 	private Context context;
 	private Map<Integer,Object> tags = new HashMap<>();
 	private Object tag;
-	int gravity = -1;  // fallback gravity for layout childs
+	int gravity = -1;  // fallback gravity for layout children
 
 	int measuredWidth = 0;
 	int measuredHeight = 0;
@@ -880,6 +880,8 @@ public class View implements Drawable.Callback {
 	private int scrollX = 0;
 	private int scrollY = 0;
 
+	ViewTreeObserver floating_observer = null;
+
 	public long widget; // pointer
 
 	private int oldWidthMeasureSpec = -1;
@@ -1236,8 +1238,17 @@ public class View implements Drawable.Callback {
 
 	public void setSelected(boolean selected) {}
 
+	public native Window native_get_window(long widget);
 	public ViewTreeObserver getViewTreeObserver() {
-		return new ViewTreeObserver();
+		Window window = native_get_window(widget);
+		if (window != null) {
+			if (window.view_tree_observer == null)
+				window.view_tree_observer = new ViewTreeObserver(window);
+			return window.view_tree_observer;
+		} else {
+			floating_observer = new ViewTreeObserver(null);
+			return floating_observer;
+		}
 	}
 
 	protected void onFinishInflate() {}
@@ -1961,8 +1972,24 @@ public class View implements Drawable.Callback {
 		keepScreenOn = screenOn;
 	}
 
-	protected void onAttachedToWindow() {}
-	protected void onDetachedFromWindow() {}
+	protected void onAttachedToWindow() {
+		if (onAttachStateChangeListener != null) {
+			onAttachStateChangeListener.onViewAttachedToWindow(this);
+		}
+		if (keepScreenOn)
+			native_keep_screen_on(widget, true);
+		if(floating_observer != null) {
+			getViewTreeObserver().merge(floating_observer);
+			floating_observer = null;
+		}
+	}
+	protected void onDetachedFromWindow() {
+		if (onAttachStateChangeListener != null) {
+			onAttachStateChangeListener.onViewDetachedFromWindow(this);
+		}
+		if (keepScreenOn)
+			native_keep_screen_on(widget, false);
+	}
 
 	public void setLayerType(int layerType, Paint paint) {}
 
@@ -2274,4 +2301,8 @@ public class View implements Drawable.Callback {
 	public Bitmap getDrawingCache() { return null; }
 
 	public void announceForAccessibility(CharSequence text) {}
+
+	public WindowInsetsController getWindowInsetsController() {
+		return native_get_window(widget).getInsetsController();
+	}
 }

src/api-impl/android/view/ViewTreeObserver.java

@@ -51,6 +51,11 @@ public final class ViewTreeObserver {
 
 	private boolean mAlive = true;
 
+	// accessed from native code
+	private long onGlobalLayout_signal_handle = 0;
+
+	private long window;
+
 	/**
 	 * Interface definition for a callback to be invoked when the view hierarchy is
 	 * attached to and detached from its window.
@@ -297,10 +302,9 @@ public final class ViewTreeObserver {
 		public void onComputeInternalInsets(InternalInsetsInfo inoutInfo);
 	}
 
-	/**
-	 * Creates a new ViewTreeObserver. This constructor should not be called
-	 */
-	ViewTreeObserver() {
+	ViewTreeObserver(Window window) {
+		if(window != null)
+			this.window = window.native_window;
 	}
 
 	/**
@@ -335,7 +339,10 @@ public final class ViewTreeObserver {
 			}
 		}
 
-		if (observer.mOnGlobalLayoutListeners != null) {
+		if (observer.mOnGlobalLayoutListeners != null && observer.mOnGlobalLayoutListeners.size() > 0) {
+			if(mOnGlobalLayoutListeners == null || mOnGlobalLayoutListeners.size() == 0)
+				native_set_have_global_layout_listeners(true);
+
 			if (mOnGlobalLayoutListeners != null) {
 				mOnGlobalLayoutListeners.addAll(observer.mOnGlobalLayoutListeners);
 			} else {
@@ -495,17 +502,11 @@ public final class ViewTreeObserver {
 			mOnGlobalLayoutListeners = new CopyOnWriteArray<OnGlobalLayoutListener>();
 		}
 
+		if (mOnGlobalLayoutListeners.size() == 0) {
+			native_set_have_global_layout_listeners(true);
+		}
+
 		mOnGlobalLayoutListeners.add(listener);
-
-		// hack: many Applications wait for the global layout before doing anything
-		// so we dispatch the event immediately
-		new Handler(Looper.getMainLooper()).post(new Runnable() {
-			@Override
-			public void run() {
-				listener.onGlobalLayout();
-			}
-		});
-
 	}
 
 	/**
@@ -539,6 +540,9 @@ public final class ViewTreeObserver {
 			return;
 		}
 		mOnGlobalLayoutListeners.remove(victim);
+
+		if(mOnGlobalLayoutListeners.size() == 0)
+			native_set_have_global_layout_listeners(false);
 	}
 
 	/**
@@ -754,6 +758,9 @@ public final class ViewTreeObserver {
 	 * @hide
 	 */
 	private void kill() {
+		/* clear any callbacks */
+		if (mOnGlobalLayoutListeners != null && mOnGlobalLayoutListeners.size() > 0)
+			native_set_have_global_layout_listeners(false);
 		mAlive = false;
 	}
 
@@ -1038,4 +1045,6 @@ public final class ViewTreeObserver {
 			getArray().clear();
 		}
 	}
+
+	private native void native_set_have_global_layout_listeners(boolean have_listeners);
 }

src/api-impl/android/view/Window.java

@@ -10,6 +10,8 @@ public class Window {
 	public static final int FEATURE_OPTIONS_PANEL = 0;
 	public static final int FEATURE_NO_TITLE = 1;
 
+	public ViewTreeObserver view_tree_observer = null;
+
 	public static interface Callback {
 		public void onContentChanged();
 
@@ -41,6 +43,11 @@ public class Window {
 		decorView.setId(android.R.id.content);
 	}
 
+	public void set_native_window(long native_window) {
+		this.native_window = native_window;
+		set_jobject(native_window, this);
+	}
+
 	public void addFlags(int flags) {}
 	public void setFlags(int flags, int mask) {}
 	public void clearFlags(int flags) {}
@@ -64,12 +71,6 @@ public class Window {
 		return decorView;
 	}
 
-	public native void set_widget_as_root(long native_window, long widget);
-	private native void set_title(long native_window, String title);
-
-	public native void take_input_queue(long native_window, InputQueue.Callback callback, InputQueue queue);
-	public native void set_layout(long native_window, int width, int height);
-
 	public void takeInputQueue(InputQueue.Callback callback) {
 		take_input_queue(native_window, callback, new InputQueue());
 	}
@@ -161,4 +162,16 @@ public class Window {
 	public void setEnterTransition(Transition transition) {}
 
 	public void setGravity(int gravity) {}
+
+	public void setDecorFitsSystemWindows(boolean fits) {}
+
+	public WindowInsetsController getInsetsController() {
+		return new InsetsController();
+	}
+
+	public native void set_widget_as_root(long native_window, long widget);
+	private native void set_title(long native_window, String title);
+	public native void take_input_queue(long native_window, InputQueue.Callback callback, InputQueue queue);
+	public native void set_layout(long native_window, int width, int height);
+	private static native void set_jobject(long ptr, Window obj);
 }