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Commit f01af755 authored by Christopher Tate's avatar Christopher Tate
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Fail more gracefully when window state changes during drags 

In particular, if a new window was created out from under the drag,
the drag-move event dispatch logic would wind up blithly assuming
that it would find a valid touch-dispatchable window under the
finger.  When this was untrue, it would NPE, but the NPE was caught
and discarded safely by higher-level guard code.

With this change, we now avoid the NPE entirely and report the
spurious condition as part of the debugging log stream.

(Also add the local-state object to DragEvent.toString()'s output.)

Change-Id: Idfa5f45d049e48415ee59c8b0ffb5b0ed4098ce3
parent 5383d077

core/java/android/view/DragEvent.java

+1 −1
Original line number Diff line number Diff line
@@ -274,7 +274,7 @@ public static final int ACTION_DRAG_EXITED = 6; 
    public String toString() {

        return "DragEvent{" + Integer.toHexString(System.identityHashCode(this))

        + " action=" + mAction + " @ (" + mX + ", " + mY + ") desc=" + mClipDescription

        + " data=" + mClipData + " result=" + mDragResult

        + " data=" + mClipData + " local=" + mLocalState + " result=" + mDragResult

        + "}";

    }

services/java/com/android/server/WindowManagerService.java

+6 −2
Original line number Diff line number Diff line
@@ -708,16 +708,20 @@ public class WindowManagerService extends IWindowManager.Stub 


            // Move the surface to the given touch

            if (SHOW_TRANSACTIONS) Slog.i(TAG, ">>> OPEN TRANSACTION notifyMoveLw");

            mSurface.openTransaction();

            Surface.openTransaction();

            try {

                mSurface.setPosition((int)(x - mThumbOffsetX), (int)(y - mThumbOffsetY));

            } finally {

                mSurface.closeTransaction();

                Surface.closeTransaction();

                if (SHOW_TRANSACTIONS) Slog.i(TAG, "<<< CLOSE TRANSACTION notifyMoveLw");

            }



            // Tell the affected window

            WindowState touchedWin = getTouchedWinAtPointLw(x, y);

            if (touchedWin == null) {

                if (DEBUG_DRAG) Slog.d(TAG, "No touched win at x=" + x + " y=" + y);

                return;

            }

            if ((mFlags & View.DRAG_FLAG_GLOBAL) == 0) {

                final IBinder touchedBinder = touchedWin.mClient.asBinder();

                if (touchedBinder != mLocalWin) {