解决异常：IllegalStateException: Fragment <ThisFragment> is not currently in the FragmentManager

上午敲代码时出现这个问题，简单记录一下解决办法，有时间详细描述一下深层原因。

问题出现在这：

[code]@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    getSupportFragmentManager().putFragment(outState, "mContent", mContent); 
}

网上查看了一下，只需修改为如下：

[code]@Override 
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    if (mFragment.isAdded()){
        getSupportFragmentManager().putFragment(outState, "mFragment", mFragment); 
    }
}

意思是：在

onSaveInstanceState(Bundle outState)

方法中保存fragment时，要先确保fragment是否已经加入到fragment manager中。