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Commit 06972aef authored by Evan Rosky's avatar Evan Rosky
Browse files

Calculate the correct surface layers for finishTransaction 

We normally prevent assignLayers from touching surface z-order
during transition animations. However, this causes a problem
when multiple transitions happen in quick succession (eg. during
CTS tests) because final surface z-order may not be updated.

To fix this, allow assignLayers to set layers into the
finishTransaction. This is applied by shell and is expected
to represent the "z-order at the end of animation", so we
obviously should allow it to get the fully calculated layers.

Bug: 237545923
Test: atest PinnedStackTests
Change-Id: Ifb8c339fcd9fce7d3457dae806b6d3b186ea5d5c
parent ca9df1de

services/core/java/com/android/server/wm/Transition.java

+8 −3
Original line number Diff line number Diff line
@@ -533,10 +533,15 @@ class Transition extends Binder implements BLASTSyncEngine.TransactionReadyListe 
        }

        // Need to update layers on involved displays since they were all paused while

        // the animation played. This puts the layers back into the correct order.

        mController.mBuildingFinishLayers = true;

        try {

            for (int i = displays.size() - 1; i >= 0; --i) {

                if (displays.valueAt(i) == null) continue;

                displays.valueAt(i).assignChildLayers(t);

            }

        } finally {

            mController.mBuildingFinishLayers = false;

        }

        if (rootLeash.isValid()) {

            t.reparent(rootLeash, null);

        }

services/core/java/com/android/server/wm/TransitionController.java

+17 −0
Original line number Diff line number Diff line
@@ -100,6 +100,14 @@ class TransitionController { 
    // TODO(b/188595497): remove when not needed.

    final StatusBarManagerInternal mStatusBar;



    /**

     * `true` when building surface layer order for the finish transaction. We want to prevent

     * wm from touching z-order of surfaces during transitions, but we still need to be able to

     * calculate the layers for the finishTransaction. So, when assigning layers into the finish

     * transaction, set this to true so that the {@link canAssignLayers} will allow it.

     */

    boolean mBuildingFinishLayers = false;



    TransitionController(ActivityTaskManagerService atm,

            TaskSnapshotController taskSnapshotController,

            TransitionTracer transitionTracer) {
@@ -309,6 +317,15 @@ class TransitionController { 
        return false;

    }



    /**

     * Whether WM can assign layers to window surfaces at this time. This is usually false while

     * playing, but can be "opened-up" for certain transition operations like calculating layers

     * for finishTransaction.

     */

    boolean canAssignLayers() {

        return mBuildingFinishLayers || !isPlaying();

    }



    @WindowConfiguration.WindowingMode

    int getWindowingModeAtStart(@NonNull WindowContainer wc) {

        if (mCollectingTransition == null) return wc.getWindowingMode();

services/core/java/com/android/server/wm/WindowContainer.java

+1 −1
Original line number Diff line number Diff line
@@ -2473,7 +2473,7 @@ class WindowContainer<E extends WindowContainer> extends ConfigurationContainer< 
    void assignLayer(Transaction t, int layer) {

        // Don't assign layers while a transition animation is playing

        // TODO(b/173528115): establish robust best-practices around z-order fighting.

        if (mTransitionController.isPlaying()) return;

        if (!mTransitionController.canAssignLayers()) return;

        final boolean changed = layer != mLastLayer || mLastRelativeToLayer != null;

        if (mSurfaceControl != null && changed) {

            setLayer(t, layer);