setLayoutManager报错了怎么解决？

Question

re_cy_1.setLayoutManager(new LinearLayoutManager(this.getActivity()));
报错：
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setLayoutManager(android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference

谢谢大家的回答，找到问题了：
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
//应该在这调用
}

Answer 1

给recyclerview设置LayoutManager，就三行代码

     LinearLayoutManager manager = new LinearLayoutManager(getContext());
        manager.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(manager);

你没有写第二句