android - 应用程序空对象引用

Question

上一个问题:
我可以知道为什么当我尝试启动 RecyclerView Activity 从 fragment 进行搜索时会发生此错误。

添加适配器后:

error: OwnerDAO.getOwner()' on a null object reference

fragment 代码:

  RecyclerView recyclerView;
  RecyclerView.LayoutManager layoutManager;
  SearchAdapter adapter;
  OwnerDAO mOwnerDao;

 public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View v = inflater.inflate(R.layout.activity_search, container, false);
    recyclerView = (RecyclerView)v.findViewById(R.id.recycler_search);
    layoutManager = new LinearLayoutManager(this.getActivity());
    mOwnerDao = new OwnerDAO(getContext())
    adapter = new SearchAdapter(getContext(),mOwnerDao.getOwner());
    recyclerView.setLayoutManager(layoutManager);
    recyclerView.setHasFixedSize(true);
    recyclerView.setAdapter( adapter );

    return v;

   }

搜索适配器:

public SearchAdapter(Context context, List<Owner> owners) {
    this.context = context;
    this.owners = owners;
}

Answer 1

像这样在 setAdapter 之后设置 layoutManager :-

  recyclerView.setAdapter( adapter );
  recyclerView.setLayoutManager(layoutManager);

错误将被删除!!