android嵌套fragment怎么实现点击外层fragment控制内层fragment显示特定界面

message是一个fragment，在里面又有两个子fragment,(Firends和follow)，后来把两个fragment改ViewPager方式进行切换，这时一定要注意msgAdapter=new FragmentMessagePagerAdapter(getChildFragmentManager());在new PagerAdapter时，一定要传入getChildFragmentManager(),而不是getSupportFragmentManager，
一级Fragment里的OnCreateView方法：

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {

mActivity = getActivity();
View view = inflater.inflate(R.layout.activity_fragment_message,container,false);

Button btnFriends= (Button) view.findViewById(R.id.btn_friends);
Button btnFollow= (Button) view.findViewById(R.id.btn_follow);
btnFriends.setOnClickListener(this);
btnFollow.setOnClickListener(this);

vp = (NoScrollViewPager) view.findViewById(R.id.vp_noscroll);

list_fragments=new ArrayList();

//把两个子fragment实例化然后装到集合里
mFrendsFragment=new Message_Friends_Fragment();
list_fragments.add(mFrendsFragment);
mFollowFragment=new Message_Follow_Fragment();
list_fragments.add(mFollowFragment);

msgAdapter=new FragmentMessagePagerAdapter(getChildFragmentManager());