有时在使用片段填充viewpager时,"活动已被破坏"

Question

我收到来自所有版本的android 4+和5+的viewpager v22 + FragmentPagerAdapter的崩溃报告.viewpager在一个片段中,寻呼机适配器正在使用childFragmentManager它很少发生,大约有1/200的用户.

java.lang.IllegalStateException: Activity has been destroyed
at android.support.v4.app.FragmentManagerImpl.void enqueueAction(java.lang.Runnable,boolean)(SourceFile:1397)
at android.support.v4.app.BackStackRecord.int commitInternal(boolean)(SourceFile:636)
at android.support.v4.app.BackStackRecord.int commitAllowingStateLoss()(SourceFile:619)
at android.support.v4.app.FragmentPagerAdapter.void finishUpdate(android.view.ViewGroup)(SourceFile:139)
at android.support.v4.view.ViewPager.void populate(int)(SourceFile:1073)
at android.support.v4.view.ViewPager.void populate()(SourceFile:919)
at android.support.v4.view.ViewPager.void onMeasure(int,int)(SourceFile:1441)
at android.view.View.measure(View.java:16574)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5140)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1406)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:697)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:590)
at android.view.View.measure(View.java:16574)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5140)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:16574)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:849)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:590)
at android.view.View.measure(View.java:16574)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5140)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:16574)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:719)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:455)
at android.view.View.measure(View.java:16574)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5140)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:16574)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5140)
at android.support.v7.internal.widget.ActionBarOverlayLayout.void onMeasure(int,int)(SourceFile:453)
at android.view.View.measure(View.java:16574)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5140)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:16574)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5140)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1406)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:697)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:590)
at android.view.View.measure(View.java:16574)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5140)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2423)
at android.view.View.measure(View.java:16574)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1955)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1151)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1333)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1038)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5890)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
at android.view.Choreographer.doCallbacks(Choreographer.java:574)
at android.view.Choreographer.doFrame(Choreographer.java:544)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5118)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:606)
at dalvik.system.NativeStart.main(Native Method)

从bugsense面包屑中,它在返回活动时发生,虽然我无法在任何内存条件下的任何设备上重现它,或者在开发者选项中"不保持活动".整个应用程序只是纵向,但从景观中的不同应用程序回来它不会导致任何问题.

我正在使用onDetach技巧,我得到"mChildFragmentManager"并将其清空,而fragmentPagerAdapter技巧可能使事情变得复杂,尽管我不相信它们会导致这个问题.

有谁知道如何一致地重现这种崩溃或如何解决它？我不知道当活动被销毁时,viewpager或片段管理器如何仍然可以处于活动状态.编辑:一些代码,以防它有帮助.

  public class HomePageAdapter extends FragmentPagerAdapter implements CustomPagerSlidingTabStrip.BadgeTabProvider {

    public HomePageAdapter(FragmentManager fm)
    {
        super(fm);
    }

     @Override
      public Parcelable saveState(){
          return new Bundle();
      }
      @Override
      public void restoreState(Parcelable arg0, ClassLoader arg1) {
          //do nothing here! no call to super.restoreState(arg0, arg1);
      }
    @Override
    public Fragment getItem(int i) {
        Fragment hf;
        switch (i){

            case 0:
                hf= MyFragment.newInstance(MyFragment.MODE_FRIENDS);
                break;
            case 1:
                hf= OtherFragment.newInstance(parameter);
                break;
            default:
                return null;

        }
        hf.setRetainInstance(false);
        return hf;
    }

    @Override
    public int getCount() {
        return 2;
    }

    @Override
    public String getPageTitle(int position) {
        switch (position){
            case 0:
                return "Tab 1";
            case 1:
                return "Tab 2";
            default:
                return "";

        }

    }

}

在我拥有的每一个片段中

    @Override
public void onDetach(){
    super.onDetach();
    try {
        Field childFragmentManager = Fragment.class.getDeclaredField("mChildFragmentManager");
        childFragmentManager.setAccessible(true);
        childFragmentManager.set(this, null);

    } catch (NoSuchFieldException e) {
        Log.e("Hang frag " ,"no such field mchildfragmentmanager err " + e.toString());
        //throw new RuntimeException(e);
    } catch (IllegalAccessException e) {
        Log.e("Hang frag " ," illegal access mchildfragmentmanager err " + e.toString());
      //  throw new RuntimeException(e);
    }
}

编辑:最新版本的支持库v4 22.2不再出现此问题.我还从适配器中删除了saveState和restoreState方法,但我怀疑这是问题所在.这可能是一个神秘的片段生命周期问题,我们永远不会知道答案.

Answer 1

如果一个人出现此问题，在某种条件下任何其他设备也一定会出现此问题。

getActivity()当您尝试获取视图寻呼机附加活动的引用并且该活动已进入静止状态时，可能会出现此问题。

如果可能，请勿通过以下方式使用活动参考：

getActivity().somemethod.something

相反，您可以在片段中创建活动的类引用onAttach()，并使用该引用来处理视图寻呼机。

希望这能解决您的问题...干杯！