片段在配置更改后丢失了过渡动画

Question

我正在使用以下代码将Fragments插入Activity:

public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    FragmentManager fm = getFragmentManager();
    String tag = "simple";

    Fragment fr = fm.findFragmentByTag(tag);
    if (fr == null)
    {
        SimpleFragment simpleFragment = new SimpleFragment(); 
        FragmentTransaction transaction = fm.beginTransaction();
        transaction.setCustomAnimations(android.R.animator.fade_in, android.R.animator.fade_out,
                                        android.R.animator.fade_in, android.R.animator.fade_out);
        transaction.add(R.id.main_layout, simpleFragment, tag);
        transaction.addToBackStack(tag);
        transaction.commit();
    }
}

片段代码是:

public class SimpleFragment extends ListFragment 
{
    @Override
    public void onActivityCreated(Bundle savedInstanceState) 
    {
        super.onActivityCreated(savedInstanceState);
        getView().setBackgroundColor(Color.YELLOW);
    }
}

当我在启动后通过Back按钮从backstack弹出片段时,一切都很好,我可以看到淡出动画.但如果我旋转设备并按"返回"按钮,则片段会在没有动画的情况下消失

这是Android行为还是我做错了什么？

编辑:似乎旋转后FragmentManager没有恢复BackStackEntry的动画(enterAnim,exitAnim,popEnterAnim和popExitAnim).

FragmentManager转储(不带旋转):

Active Fragments in 4087d668:
  #0: SimpleFragment{408883b0 #0 id=0x7f050000 simple}
    mFragmentId=#7f050000 mContainerId#=7f050000 mTag=simple
    mState=4 mIndex=0 mWho=android:fragment:0 mBackStackNesting=1
    mAdded=true mRemoving=false mResumed=true mFromLayout=false mInLayout=false
    mHidden=false mDetached=false mRetainInstance=false mRetaining=false mHasMenu=false
    mFragmentManager=FragmentManager{4087d668 in ListViewFragmentsActivity{4087d588}}
    mImmediateActivity=my.app.ListViewFragmentsActivity@4087d588
    mActivity=my.app.ListViewFragmentsActivity@4087d588
    mNextAnim=17498112
    mContainer=android.widget.RelativeLayout@408876d8
    mView=android.widget.FrameLayout@40888a70
Added Fragments:
  #0: SimpleFragment{408883b0 #0 id=0x7f050000 simple}
Back Stack:
  #0: android.app.BackStackRecord@408884b8
    mName=simple mIndex=0 mCommitted=true
    mEnterAnim=#10b0000 mExitAnim=#10b0001
    Operations:
      Op #0:
        cmd=1 fragment=SimpleFragment{408883b0 #0 id=0x7f050000 simple}
    enterAnim=17498112 exitAnim=17498113
    popEnterAnim=17498112 popExitAnim=17498113
Back Stack Indices:
  #0: android.app.BackStackRecord@408884b8
FragmentManager misc state:
  mCurState=5 mStateSaved=false mDestroyed=false

FragmentManager转储(旋转后):

Active Fragments in 40877f38:
  #0: SimpleFragment{40878858 #0 id=0x7f050000 simple}
    mFragmentId=#7f050000 mContainerId#=7f050000 mTag=simple
    mState=4 mIndex=0 mWho=android:fragment:0 mBackStackNesting=1
    mAdded=true mRemoving=false mResumed=true mFromLayout=false mInLayout=false
    mHidden=false mDetached=false mRetainInstance=false mRetaining=false mHasMenu=false
    mFragmentManager=FragmentManager{40877f38 in ListViewFragmentsActivity{40877e58}}
    mImmediateActivity=my.app.ListViewFragmentsActivity@40877e58
    mActivity=my.app.ListViewFragmentsActivity@40877e58
    mContainer=android.widget.RelativeLayout@4087ed50
    mView=android.widget.FrameLayout@4087fc00
Added Fragments:
  #0: SimpleFragment{40878858 #0 id=0x7f050000 simple}
Back Stack:
  #0: android.app.BackStackRecord@40878a78
    mName=simple mIndex=0 mCommitted=false
    Operations:
      Op #0:
        cmd=1 fragment=SimpleFragment{40878858 #0 id=0x7f050000 simple}
Back Stack Indices:
  #0: android.app.BackStackRecord@40878a78
FragmentManager misc state:
  mCurState=5 mStateSaved=false mDestroyed=false

Answer 1

作为解决方法,您可以在片段中使用onCreateAnimator/onCreateAnimation方法.

例如,对于本机片段实现:

@Override
public Animator onCreateAnimator(int transit, boolean enter, int nextAnim) {
    if (enter) {
        return AnimatorInflater.loadAnimator(getActivity(), R.animator.slide_in_top);
    } else {
        return AnimatorInflater.loadAnimator(getActivity(), R.animator.fade_out);
    }
}

相反,使用Animation支持库片段的技术相同.在这种情况下,您还可以根据片段状态和/或参数更好地控制播放动画的方式.

Answer 2

好吧，这是一个错误，这也是本机库（不仅仅是支持库）的问题。

我可以建议的唯一解决方法是创建您自己的返回堆栈，然后使用您自己的自定义实现处理 onBack，在您返回自己的堆栈时设置正确的动画。