android - SharedElement和自定义EnterTransition导致内存泄漏

具有共享元素动画以及自定义输入动画会导致 Activity 泄漏。

知道可能是什么原因吗？
09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * com.feeln.android.activity.MovieDetailActivity has leaked:09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * GC ROOT android.app.ActivityThread$ApplicationThread.this$009-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references android.app.ActivityThread.mActivities09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references android.util.ArrayMap.mArray09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references array java.lang.Object[].[1]09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references android.app.ActivityThread$ActivityClientRecord.activity09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references com.feeln.android.activity.MovieDetailActivity.mActivityTransitionState09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references android.app.ActivityTransitionState.mEnterTransitionCoordinator09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references android.app.EnterTransitionCoordinator.mEnterViewsTransition09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references android.transition.TransitionSet.mParent09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references android.transition.TransitionSet.mListeners09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references java.util.ArrayList.array09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references array java.lang.Object[].[1]09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references android.transition.TransitionManager$MultiListener$1.val$runningTransitions (anonymous class extends android.transition.Transition$TransitionListenerAdapter)09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references android.util.ArrayMap.mArray09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references array java.lang.Object[].[2]09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * references com.android.internal.policy.impl.PhoneWindow$DecorView.mContext09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * leaks com.feeln.android.activity.MovieDetailActivity instance09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ [ 09-21 16:19:31.007 28269:31066 D/LeakCanary ] * Reference Key: af2b6234-297e-4bab-96e9-02f1c4bca17109-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * Device: LGE google Nexus 5 hammerhead09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * Android Version: 5.1.1 API: 22 LeakCanary: 1.3.109-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ * Durations: watch=6785ms, gc=262ms, heap dump=8553ms, analysis=33741ms09-21 16:19:31.007 28269-31066/com.sample.android D/LeakCanary﹕ [ 09-21 16:19:31.007 28269:31066 D/LeakCanary ]
要进行复制，您需要具有较大的共享图像动画，还需要自定义EnterAnimation和setEnterSharedElementCallback。所有这些都来自支持库。

这是我设置EnterTransition的方法:

private SharedElementCallback mCallback = new SharedElementCallback() {
    @Override
    public void onSharedElementStart(List<String> sharedElementNames, List<View> sharedElements, List<View> sharedElementSnapshots) {
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
        {
            if(sharedElements.size()>0)
                getWindow().setEnterTransition(makeEnterTransition(getWindow().getEnterTransition(), getSharedElement(sharedElements)));
        }
    }


    private View getSharedElement(List<View> sharedElements)
    {
        for (final View view : sharedElements)
        {
            if (view instanceof ImageView)
            {
                return view;
            }
        }
        return null;
    }
};

最佳答案

泄漏的情况发生在TransitionManager.sRunningTransitions中，其中每个DecorView都会添加，而不会删除。 DecorView链接到他的Activity的Context。由于sRunningTransitions是静态字段，因此它具有对Activity的永久引用链，GC永远不会收集它。

我不知道为什么需要TransitionManager.sRunningTransitions，但是如果从其中删除Activity的DecorView，您的问题将得到解决。遵循代码为例，该怎么做。在您的 Activity 课中:

@Override
protected void onDestroy() {
    super.onDestroy();
    removeActivityFromTransitionManager(Activity activity);
}

private static void removeActivityFromTransitionManager(Activity activity) {
    if (Build.VERSION.SDK_INT < 21) {
        return;
    }
    Class transitionManagerClass = TransitionManager.class;
    try {
        Field runningTransitionsField = transitionManagerClass.getDeclaredField("sRunningTransitions");
            runningTransitionsField.setAccessible(true);
        //noinspection unchecked
        ThreadLocal<WeakReference<ArrayMap<ViewGroup, ArrayList<Transition>>>> runningTransitions
                = (ThreadLocal<WeakReference<ArrayMap<ViewGroup, ArrayList<Transition>>>>)
                runningTransitionsField.get(transitionManagerClass);
        if (runningTransitions.get() == null || runningTransitions.get().get() == null) {
            return;
        }
        ArrayMap map = runningTransitions.get().get();
        View decorView = activity.getWindow().getDecorView();
        if (map.containsKey(decorView)) {
            map.remove(decorView);
        }
    } catch (NoSuchFieldException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    }
}

关于android - SharedElement和自定义EnterTransition导致内存泄漏，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/32698049/