android第一次渲染数据为空

Question

public class RecyclerFragment extends Fragment{

private View view;
private ArrayList<ForumEntity> forumEntities =new ArrayList<>();
private NewmyAdapter newmyAdapter;
private Gson mGson=new Gson();

public ArrayList<ForumEntity> getForumEntities() {
    return forumEntities;
}

public void setForumEntities(ArrayList<ForumEntity> forumEntities) {
    this.forumEntities = forumEntities;
    newmyAdapter=new NewmyAdapter(forumEntities,getActivity());//进入适配器Adapter，转换数据
    RecyclerView recyclerView=view.findViewById(R.id.rv);
    recyclerView.setAdapter(newmyAdapter);
}

@NonNull
@Override
public View onCreateView(@NonNull LayoutInflater inflater,@NonNull ViewGroup container,@NonNull Bundle saveInstanceState){
    view = inflater.inflate(R.layout.fragment_recycler,container,false);
    initdata();
    List<ForumEntity>temp=forumEntities;
    RecyclerView recyclerView=view.findViewById(R.id.rv);
    LinearLayoutManager linearLayoutManager=new LinearLayoutManager(getActivity());
    recyclerView.setLayoutManager(linearLayoutManager);

    newmyAdapter=new NewmyAdapter(forumEntities,getActivity());//进入适配器Adapter，转换数据
    recyclerView.setAdapter(newmyAdapter);
    newmyAdapter.setRecyclerItemClickListener(new NewmyAdapter.OnRecyclerItemClickListener() {
        @Override
        public void onRecyclerItemclick(int position) {
            System.out.println(forumEntities.get(position).getFo_id());
        }
    });
    return view;

}

private void initdata(){
    try {
        OkHttpUtils.getInstance().doGet("http://192.168.161.1:8081/selectForum", new MyCallBack() {
            @Override
            public void onSuccess(String result) {
                Type type=new TypeToken<List<ForumEntity>>(){}.getType();
                forumEntities= mGson.fromJson(result,type);
                if(forumEntities.isEmpty()){
                    System.out.println("wowowowowowowoooooooooooooo");
                }else{
                    System.out.println("yoyouyouyouyouyouyouyoyou");
                }
            }
            @Override
            public void onError(Exception e) {
                Toast.makeText(getActivity(),"Error",Toast.LENGTH_SHORT).show();
            }
        });
    }
    catch (Exception e) {
        e.printStackTrace();
    }
}

}
为什么第一次拿到的forumentities是null的呢？第二次才不为空。？

Answer 1

你得对比你的实体类和拿到的数据result JSON字符串结果是不是一致的，看看是不是是少了什么参数