Question

在recyclerView.setAdapter（adapter）中通过NullPointerException实现RecyclerView片段。在QuestionScreen.java中

- 请帮忙。

Fragment- QuestionScreen.java

import android.os.Bundle;
import android.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import static com.example.activist.theactivistchallenge.R.layout.questionscreen;

    public class QuestionScreen extends Fragment {

    RecyclerView recyclerView;



    public QuestionScreen() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootview = inflater.inflate(questionscreen, container, false);
        recyclerView = (RecyclerView) rootview.findViewById(R.id.question_recycler_view);

        RecyclerAdapter adapter = new RecyclerAdapter(getActivity());
        recyclerView.setAdapter(adapter);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

        return rootview;
    }

}

RecyclerAdapter.java

    package com.example.activist.theactivistchallenge;

    import android.content.Context;
    import android.support.v7.widget.RecyclerView;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.Toast;

    public class RecyclerAdapter extends  RecyclerView.Adapter<RecyclerViewHolder> {

    String [] name={"Androidwarriors","Stackoverflow","Developer Android","AndroidHive",
            "Slidenerd","TheNewBoston","Truiton","HmkCode","JavaTpoint","Javapeper"};
    Context context;
    LayoutInflater inflater;
    public RecyclerAdapter(Context context) {
        this.context=context;
        inflater=LayoutInflater.from(context);
    }
    @Override
    public RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v=inflater.inflate(R.layout.questionscreen_list, parent, false);

        RecyclerViewHolder viewHolder=new RecyclerViewHolder(v);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(RecyclerViewHolder holder, int position) {

        holder.question_desc.setText(name[position]);
    }




    @Override
    public int getItemCount() {
        return name.length;
    }
}

Answer 1

如果找不到视图，

rootview.findViewById(R.id.question_recycler_view)可能会返回null。

您确定R.layout.questionscreen中有ID为R.id.question_recycler_view的视图吗？我不是。

通过NullPointerException实现RecyclerView片段

1 个答案: