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Commit e9d32ea1 authored by Chet Haase's avatar Chet Haase
Browse files

Starting new transition cancels running transition 

The behavior of running a transition is janky and unpredictable,
when there is already a transition running on the same scene root.
Usually, the new transition simply jumps to the end values, or
jumps to the start values for that transition and animates from
there.

A better approach is to cancel any running transition first, the
start the new transition from that point.

Even better would be to blend old/new transitions, or at least adjust
the animation timing according to where/when the previous transition
stopped. In the meantime, this fix is at least better than the
previous approach of ignoring running transitions.

Change-Id: I4f5fabb55f6454f1e9d66589a9a7c36f9fc013fb
parent 90b89944

core/java/android/view/transition/Transition.java

+28 −6
Original line number Diff line number Diff line
@@ -78,6 +78,10 @@ public abstract class Transition { 
    private ArrayList<TransitionValues> mPlayStartValuesList = new ArrayList<TransitionValues>();

    private ArrayList<TransitionValues> mPlayEndValuesList = new ArrayList<TransitionValues>();



    // Track all animators in use in case the transition gets canceled and needs to

    // cancel running animators

    private ArrayList<Animator> mCurrentAnimators = new ArrayList<Animator>();



    // Number of per-target instances of this Transition currently running. This count is

    // determined by calls to startTransition() and endTransition()

    int mNumInstances = 0;
@@ -401,13 +405,30 @@ public abstract class Transition { 
            TransitionValues start = mPlayStartValuesList.get(i);

            TransitionValues end = mPlayEndValuesList.get(i);

            startTransition();

            animate(play(sceneRoot, start, end));

            runAnimator(play(sceneRoot, start, end));

        }

        mPlayStartValuesList.clear();

        mPlayEndValuesList.clear();

        endTransition();

    }



    private void runAnimator(Animator animator) {

        if (animator != null) {

            // TODO: could be a single listener instance for all of them since it uses the param

            animator.addListener(new AnimatorListenerAdapter() {

                @Override

                public void onAnimationStart(Animator animation) {

                    mCurrentAnimators.add(animation);

                }

                @Override

                public void onAnimationEnd(Animator animation) {

                    mCurrentAnimators.remove(animation);

                }

            });

            animate(animator);

        }

    }



    /**

     * Captures the current scene of values for the properties that this

     * transition monitors. These values can be either the start or end
@@ -667,11 +688,6 @@ public abstract class Transition { 
                animator.setInterpolator(getInterpolator());

            }

            animator.addListener(new AnimatorListenerAdapter() {

                @Override

                public void onAnimationCancel(Animator animation) {

                    cancelTransition();

                }



                @Override

                public void onAnimationEnd(Animator animation) {

                    endTransition();
@@ -771,6 +787,7 @@ public abstract class Transition { 
            mEndValues.clear();

            mEndIdValues.clear();

            mEndItemIdValues.clear();

            mCurrentAnimators.clear();

        }

    }
@@ -781,6 +798,11 @@ public abstract class Transition { 
    protected void cancelTransition() {

        // TODO: how does this work with instances?

        // TODO: this doesn't actually do *anything* yet

        int numAnimators = mCurrentAnimators.size();

        for (int i = 0; i < numAnimators; ++i) {

            Animator animator = mCurrentAnimators.get(i);

            animator.cancel();

        }

        onTransitionCancel();

        if (mListeners != null && mListeners.size() > 0) {

            ArrayList<TransitionListener> tmpListeners =

core/java/android/view/transition/TransitionGroup.java

+9 −0
Original line number Diff line number Diff line
@@ -302,6 +302,15 @@ public class TransitionGroup extends Transition { 
        }

    }



    @Override

    protected void cancelTransition() {

        super.cancelTransition();

        int numTransitions = mTransitions.size();

        for (int i = 0; i < numTransitions; ++i) {

            mTransitions.get(i).cancelTransition();

        }

    }



    @Override

    String toString(String indent) {

        String result = super.toString(indent);

core/java/android/view/transition/TransitionManager.java

+16 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
 */

package android.view.transition;



import android.util.ArrayMap;

import android.view.ViewGroup;

import android.view.ViewTreeObserver;
@@ -40,6 +41,8 @@ public class TransitionManager { 
    HashMap<Scene, Transition> mSceneTransitions = new HashMap<Scene, Transition>();

    HashMap<Scene, HashMap<Scene, Transition>> mScenePairTransitions =

            new HashMap<Scene, HashMap<Scene, Transition>>();

    static ArrayMap<ViewGroup, Transition> sRunningTransitions =

            new ArrayMap<ViewGroup, Transition>();



        /**

     * Sets the transition to be used for any scene change for which no
@@ -141,6 +144,11 @@ public class TransitionManager { 


        final ViewGroup sceneRoot = scene.getSceneRoot();



        Transition runningTransition = sRunningTransitions.get(sceneRoot);

        if (runningTransition != null) {

            runningTransition.cancelTransition();

        }



        // Capture current values

        if (transition != null) {

            transition.captureValues(sceneRoot, true);
@@ -159,6 +167,14 @@ public class TransitionManager { 
            observer.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {

                public boolean onPreDraw() {

                    sceneRoot.getViewTreeObserver().removeOnPreDrawListener(this);

                    // Add to running list, handle end to remove it

                    sRunningTransitions.put(sceneRoot, transition);

                    transition.addListener(new Transition.TransitionListenerAdapter() {

                        @Override

                        public void onTransitionEnd(Transition transition) {

                            sRunningTransitions.remove(sceneRoot);

                        }

                    });

                    transition.captureValues(sceneRoot, false);

                    transition.play(sceneRoot);

                    return true;