异常：
java.lang.IllegalStateException: Activity has been destroyed
at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1342)
at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:595)
at android.support.v4.app.BackStackRecord.commitAllowingStateLoss(BackStackRecord.java:578)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:139)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1012)
at android.support.v4.view.ViewPager.populate(ViewPager.java:881)
at android.support.v4.view.ViewPager.setAdapter(ViewPager.java:434)
at com.itcode.reader.fragment.MineFragment.onViewCreated(MineFragment.java:49)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:925)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1088)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1444)
at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:429)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
场景：
Fragment中有一个ViewPager,ViewPager的每一个pager为Fragment
调用代码：
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
viewPager = (ViewPager) view.findViewById(R.id.pager);
ViewPagerAdapter adapter = new ViewPagerAdapter(getChildFragmentManager(),TITLE);
viewPager.setAdapter(adapter);
TabPageIndicator mIndicator = (TabPageIndicator) view.findViewById(R.id.indicator);
mIndicator.setViewPager(viewPager);
}
解决方式：
在每一个调用getChildFragmentManager()的fragment中增加：
@Override
public void onDetach() {
super.onDetach();
try {
Field childFragmentManager = Fragment.class.getDeclaredField("mChildFragmentManager");
childFragmentManager.setAccessible(true);
childFragmentManager.set(this, null);
} catch (NoSuchFieldException e) {
throw new RuntimeException(e);
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
}
}
就可以！
异常解析：
假设你细致查看Fragment的实现，你会看到当fragment进行到detached状态时，它会重置它的内部状态。
然而，它没有重置mChildFragmentManager.这是当前版本号support库的一个bug.
这导致在Fragment又一次attach时，它(fragment)没有又一次attachm childFragmentManager。从而引发了上面的异常.