作者：angerlie更新於 08月20日訪問（970）評論（2）
1.bug的log
java.lang.IllegalStateException: No activity
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1075)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1070)
at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:1861)
at android.support.v4.app.Fragment.performActivityCreated(Fragment.java:1474)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:931)
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.executePendingTransactions(FragmentManager.java:461)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1011)
at android.support.v4.view.ViewPager.populate(ViewPager.java:880)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1374)
2.出現場景
第一次啓動程序可以正常運行，隨便切換tab也不會有問題，第二次必崩！
3.bug出現的原理及如何修復
This seems to be a bug in the newly added support for nested fragments. Basically, the child FragmentManager ends up with a broken internal state when it is detached from the activity. A short-term workaround that fixed it for me is to add the following to
onDetach() of every Fragment which you call getChildFragmentManager() on:
@Override
public void onDetach() {
super.onDetach();
1 2 3 4 5 6 7 8 9 10 |
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);
}
|
}
4.是什麼引起的bug
If you look at the implementation of Fragment, you'll see that when moving to the detached state, it'll reset its internal state. However, it doesn't reset mChildFragmentManager (this is a bug in the current version of the support library). This causes it to
not reattach the child fragment manager when the Fragment is reattached, causing the exception you saw.