錯誤提示：

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)

.......

這個問題是在解決上一篇文章（http://blog.csdn.net/leewenjin/article/details/19409863）中指出的問題後出現的。問題解決方法是參考文章：

http://stackoverflow.com/questions/15207305/getting-the-error-java-lang-illegalstateexception-activity-has-been-destroyed

bug出現的原理問題及解決方法是
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:

解決方法重寫onDetach()

1. @Override  
2.     public void onDetach() {  
3.         super.onDetach();  
4.         try {  
5.             Field childFragmentManager = Fragment.class.getDeclaredField("mChildFragmentManager");  
6.             childFragmentManager.setAccessible(true);  
7.             childFragmentManager.set(this, null);  
8.   
9.         } catch (NoSuchFieldException e) {  
10.             throw new RuntimeException(e);  
11.         } catch (IllegalAccessException e) {  
12.             throw new RuntimeException(e);  
13.         }  
14.       
15.     }  

引起bug的原因
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.