Eliminating the “black hole” effect with location/drop events. (1edc6daf) · Commits · e / os / android_frameworks_base

core/java/android/view/DragEvent.java

+2 −0

Original line number	Diff line number	Diff line
		@@ -134,6 +134,7 @@ public class DragEvent implements Parcelable {

		Object mLocalState;
		boolean mDragResult;
		boolean mEventHandlerWasCalled;

		private DragEvent mNext;
		private RuntimeException mRecycledLocation;
		@@ -435,6 +436,7 @@ public class DragEvent implements Parcelable {
		mClipData = null;
		mClipDescription = null;
		mLocalState = null;
		mEventHandlerWasCalled = false;

		synchronized (gRecyclerLock) {
		if (gRecyclerUsed < MAX_RECYCLED) {

core/java/android/view/View.java

+11 −1

Original line number	Diff line number	Diff line
		@@ -40,7 +40,6 @@ import android.content.res.Resources;
		import android.content.res.TypedArray;
		import android.graphics.Bitmap;
		import android.graphics.Canvas;
		import android.graphics.Color;
		import android.graphics.Insets;
		import android.graphics.Interpolator;
		import android.graphics.LinearGradient;
		@@ -20874,6 +20873,17 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
		* </p>
		*/
		public boolean dispatchDragEvent(DragEvent event) {
		event.mEventHandlerWasCalled = true;
		if (event.mAction == DragEvent.ACTION_DRAG_LOCATION \|\|
		event.mAction == DragEvent.ACTION_DROP) {
		// About to deliver an event with coordinates to this view. Notify that now this view
		// has drag focus. This will send exit/enter events as needed.
		getViewRootImpl().setDragFocus(this, event);
		}
		return callDragEventHandler(event);
		}

		final boolean callDragEventHandler(DragEvent event) {
		ListenerInfo li = mListenerInfo;
		//noinspection SimplifiableIfStatement
		if (li != null && li.mOnDragListener != null && (mViewFlags & ENABLED_MASK) == ENABLED

core/java/android/view/ViewGroup.java

+10 −103

Original line number	Diff line number	Diff line
		@@ -153,9 +153,6 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
		*/
		Transformation mInvalidationTransformation;

		// View currently under an ongoing drag. Can be null, a child or this window.
		private View mCurrentDragView;

		// Metadata about the ongoing drag
		private DragEvent mCurrentDragStartEvent;
		private boolean mIsInterestedInDrag;
		@@ -1362,16 +1359,11 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
		final float tx = event.mX;
		final float ty = event.mY;

		ViewRootImpl root = getViewRootImpl();

		// Dispatch down the view hierarchy
		final PointF localPoint = getLocalPoint();

		switch (event.mAction) {
		case DragEvent.ACTION_DRAG_STARTED: {
		// clear state to recalculate which views we drag over
		mCurrentDragView = null;

		// Set up our tracking of drag-started notifications
		mCurrentDragStartEvent = DragEvent.obtain(event);
		if (mChildrenInterestedInDrag == null) {
		@@ -1434,60 +1426,15 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
		}
		} break;

		case DragEvent.ACTION_DRAG_LOCATION: {
		case DragEvent.ACTION_DRAG_LOCATION:
		case DragEvent.ACTION_DROP: {
		// Find the [possibly new] drag target
		View target = findFrontmostDroppableChildAt(event.mX, event.mY, localPoint);
		if (target == null && mIsInterestedInDrag) {
		target = this;
		}

		// If we've changed apparent drag target, tell the view root which view
		// we're over now [for purposes of the eventual drag-recipient-changed
		// notifications to the framework] and tell the new target that the drag
		// has entered its bounds. The root will see setDragFocus() calls all
		// the way down to the final leaf view that is handling the LOCATION event
		// before reporting the new potential recipient to the framework.
		if (mCurrentDragView != target) {
		root.setDragFocus(target);

		final int action = event.mAction;
		// Position should not be available for ACTION_DRAG_ENTERED and ACTION_DRAG_EXITED.
		event.mX = 0;
		event.mY = 0;

		// If we've dragged off of a child view or this window, send it the EXITED message
		if (mCurrentDragView != null) {
		final View view = mCurrentDragView;
		event.mAction = DragEvent.ACTION_DRAG_EXITED;
		if (view != this) {
		view.dispatchDragEvent(event);
		view.mPrivateFlags2 &= ~View.PFLAG2_DRAG_HOVERED;
		view.refreshDrawableState();
		} else {
		super.dispatchDragEvent(event);
		}
		}

		mCurrentDragView = target;

		// If we've dragged over a new child view, send it the ENTERED message, otherwise
		// send it to this window.
		if (target != null) {
		event.mAction = DragEvent.ACTION_DRAG_ENTERED;
		if (target != this) {
		target.dispatchDragEvent(event);
		target.mPrivateFlags2 \|= View.PFLAG2_DRAG_HOVERED;
		target.refreshDrawableState();
		} else {
		super.dispatchDragEvent(event);
		}
		}
		event.mAction = action; // restore the event's original state
		event.mX = tx;
		event.mY = ty;
		}

		// Dispatch the actual drag location notice, localized into its coordinates
		// Dispatch the actual drag notice, localized into the target coordinates.
		if (target != null) {
		if (target != this) {
		event.mX = localPoint.x;
		@@ -1497,55 +1444,14 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager

		event.mX = tx;
		event.mY = ty;
		} else {

		if (!event.mEventHandlerWasCalled && mIsInterestedInDrag) {
		// The child didn't invoke any event handler, but this view is interested in
		// drag, so the event goes to this view.
		retval = super.dispatchDragEvent(event);
		}
		}
		} break;

		/* Entered / exited dispatch
		*
		* DRAG_ENTERED is not dispatched downwards from ViewGroup. The reason for this is
		* that we're about to get the corresponding LOCATION event, which we will use to
		* determine which of our children is the new target; at that point we will
		* push a DRAG_ENTERED down to the new target child [which may itself be a ViewGroup].
		* If no suitable child is detected, dispatch to this window.
		*
		* DRAG_EXITED is dispatched all the way down immediately: once we know the
		* drag has left this ViewGroup, we know by definition that every contained subview
		* is also no longer under the drag point.
		*/

		case DragEvent.ACTION_DRAG_EXITED: {
		if (mCurrentDragView != null) {
		final View view = mCurrentDragView;
		if (view != this) {
		view.dispatchDragEvent(event);
		view.mPrivateFlags2 &= ~View.PFLAG2_DRAG_HOVERED;
		view.refreshDrawableState();
		} else {
		super.dispatchDragEvent(event);
		}

		mCurrentDragView = null;
		}
		} break;

		case DragEvent.ACTION_DROP: {
		if (ViewDebug.DEBUG_DRAG) Log.d(View.VIEW_LOG_TAG, "Drop event: " + event);
		View target = findFrontmostDroppableChildAt(event.mX, event.mY, localPoint);
		if (target != null) {
		if (ViewDebug.DEBUG_DRAG) Log.d(View.VIEW_LOG_TAG, " dispatch drop to " + target);
		event.mX = localPoint.x;
		event.mY = localPoint.y;
		retval = target.dispatchDragEvent(event);
		event.mX = tx;
		event.mY = ty;
		} else if (mIsInterestedInDrag) {
		retval = super.dispatchDragEvent(event);
		} else {
		if (ViewDebug.DEBUG_DRAG) {
		Log.d(View.VIEW_LOG_TAG, " not dropped on an accepting view");
		}
		}
		} break;
		@@ -1592,6 +1498,7 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
		final boolean canAccept = child.dispatchDragEvent(mCurrentDragStartEvent);
		mCurrentDragStartEvent.mX = tx;
		mCurrentDragStartEvent.mY = ty;
		mCurrentDragStartEvent.mEventHandlerWasCalled = false;
		if (canAccept) {
		mChildrenInterestedInDrag.add(child);
		if (!child.canAcceptDrag()) {

core/java/android/view/ViewRootImpl.java

+37 −4

Original line number	Diff line number	Diff line
		@@ -5523,9 +5523,8 @@ public final class ViewRootImpl implements ViewParent,
		if (what == DragEvent.ACTION_DRAG_EXITED) {
		// A direct EXITED event means that the window manager knows we've just crossed
		// a window boundary, so the current drag target within this one must have
		// just been exited. Send it the usual notifications and then we're done
		// for now.
		mView.dispatchDragEvent(event);
		// just been exited. Send the EXITED notification to the current drag view, if any.
		setDragFocus(null, event);
		} else {
		// For events with a [screen] location, translate into window coordinates
		if ((what == DragEvent.ACTION_DRAG_LOCATION) \|\| (what == DragEvent.ACTION_DROP)) {
		@@ -5548,6 +5547,12 @@ public final class ViewRootImpl implements ViewParent,
		// Now dispatch the drag/drop event
		boolean result = mView.dispatchDragEvent(event);

		if (what == DragEvent.ACTION_DRAG_LOCATION && !event.mEventHandlerWasCalled) {
		// If the LOCATION event wasn't delivered to any handler, no view now has a drag
		// focus.
		setDragFocus(null, event);
		}

		// If we changed apparent drag target, tell the OS about it
		if (prevDragView != mCurrentDragView) {
		try {
		@@ -5575,6 +5580,7 @@ public final class ViewRootImpl implements ViewParent,

		// When the drag operation ends, reset drag-related state
		if (what == DragEvent.ACTION_DRAG_ENDED) {
		mCurrentDragView = null;
		setLocalDragState(null);
		mAttachInfo.mDragToken = null;
		if (mAttachInfo.mDragSurface != null) {
		@@ -5634,9 +5640,36 @@ public final class ViewRootImpl implements ViewParent,
		return mLastTouchSource;
		}

		public void setDragFocus(View newDragTarget) {
		public void setDragFocus(View newDragTarget, DragEvent event) {
		if (mCurrentDragView != newDragTarget) {
		// Send EXITED and ENTERED notifications to the old and new drag focus views.

		final float tx = event.mX;
		final float ty = event.mY;
		final int action = event.mAction;
		// Position should not be available for ACTION_DRAG_ENTERED and ACTION_DRAG_EXITED.
		event.mX = 0;
		event.mY = 0;

		if (mCurrentDragView != null) {
		event.mAction = DragEvent.ACTION_DRAG_EXITED;
		mCurrentDragView.callDragEventHandler(event);
		mCurrentDragView.mPrivateFlags2 &= ~View.PFLAG2_DRAG_HOVERED;
		mCurrentDragView.refreshDrawableState();
		}

		mCurrentDragView = newDragTarget;

		if (newDragTarget != null) {
		event.mAction = DragEvent.ACTION_DRAG_ENTERED;
		newDragTarget.callDragEventHandler(event);
		newDragTarget.mPrivateFlags2 \|= View.PFLAG2_DRAG_HOVERED;
		newDragTarget.refreshDrawableState();
		}

		event.mAction = action;
		event.mX = tx;
		event.mY = ty;
		}
		}