java.lang.IllegalStateException: Activity has been destroyed怎么解决

Activty嵌套多个Fragment，然后Fragment里面再嵌套多个Fragment，外层的Fragment切换得快了或者横竖屏切换就会报错：
java.lang.IllegalStateException: Activity has been destroyed
at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1460)
at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:634)
at android.support.v4.app.BackStackRecord.commit(BackStackRecord.java:613)
怎么解决？

报错的是外层Fragment内的下面这段代码：

IndexListFragment indexHotFragment = new IndexListFragment();
Bundle bundle = new Bundle();
switch (id) {
    case 1:
        bundle.putSerializable("list", audit_handles);
        bundle.putInt("id", 1);
        break;
    case 2:
        bundle.putSerializable("list", pos_handles);
        bundle.putInt("id", 2);
        break;
    case 3:
        bundle.putSerializable("list", audit_lists);
        bundle.putInt("id", 3);
        break;
    case 4:
        bundle.putSerializable("list", pos_lists);
        bundle.putInt("id", 4);
        break;
    default:
        break;
    }
    indexHotFragment.setArguments(bundle);
    FragmentManager fragmentManager = getChildFragmentManager();
    FragmentTransaction ft = fragmentManager.beginTransaction();
    ft.replace(flContainer, indexHotFragment);
    ft.commit();
        

然后我查了网上的资料，都说加下面一段：

@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);
    }
}

这个方法怎么用，“mChildFragmentManager”需要替换成什么，，感觉不管用呢？

---

其实有一个办法是
if(getActivity()==null){
return;
}
if(getActivity().isFishing()){
return;
}
不知道你是否能理解我的意思。

---

你需要恢复FragmentManager中为你保存的fragment.
在创建fragment之前,判断一下savedInstanceState,像这样:

    @Override
    public void onViewStateRestored(@Nullable Bundle savedInstanceState) {

        super.onViewStateRestored(savedInstanceState);
        if (savedInstanceState != null) {
            FragmentManager fm = getChildFragmentManager();
            // tag 是你在add fragment的时候穿进去的值.
            mFragment = (Fragment) fm.findFragmentByTag(tag);
        }
    }

另外,我好奇你fragment嵌套的时候,是怎么add进去的.不会也是用反射得到mChildFragmentManager然后再操作的吧?
getChildFragmentManager()就可以得到childFragmentManager.

具体可以参见 https://.com/q/10...