Question

它给了我一个空白的活动而没有显示我的列表..我不知道是什么错误。谁能帮忙？这是我的代码：

    public class Home extends AppCompatActivity implements HomeCallBack {

    public ArrayList<info> info;
    private  Adaptor myadaptor;
    private RecyclerView recyclerView;
    private RecyclerView.LayoutManager layoutManager;


    @Override
     protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);
        recyclerView=(RecyclerView)findViewById(R.id.recycle_view);

        BackgroundHome backgroundHome=new BackgroundHome(this,this);
        backgroundHome.execute();


    }

    @Override
    public void processData(JSONArray data)
    {

        JSONObject js;

                if(data!=null)
                {
                     info=new ArrayList<>();

                    try
                    {
                        for(int i=0;i<data.length();i++)
                        {
                            js =data.getJSONObject(i);
                            info in=new info(js.getString("Names"),js.getString("city"),js.getString("university"));
                            info.add( in);




                        }



                        myadaptor=new Adaptor(info);

                        recyclerView.addItemDecoration(new DividerItemDecoration(this, LinearLayoutManager.VERTICAL));
                        LinearLayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
                        recyclerView.setLayoutManager(mLayoutManager);
                        recyclerView.setItemAnimator(new DefaultItemAnimator());
                        recyclerView.setAdapter( myadaptor);

当我在create方法中调用recyclelerView.setAdapter（myadapter）时，它会给我一个错误和app停止。这是我的适配器代码：

public class Adaptor extends RecyclerView.Adapter<Adaptor.ViewHolder> {


private  ArrayList<info> info;

public Adaptor(ArrayList<info> info) {
    this.info = info;
}


public void updateList(ArrayList<info> data) {
   info = data;
    notifyDataSetChanged();
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {


    View itemView = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.list_view, parent, false);

         return new ViewHolder(itemView);


}



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

    info i= info.get(position);
    holder.name.setText(i.getName());
    holder.city.setText(i.getCity());
    holder.city.setText(i.getUniversity());


}

@Override
public int getItemCount() {
    return info.size();
}


public class ViewHolder extends RecyclerView.ViewHolder {

    TextView name, city, uni;


    public ViewHolder(final View v) {
        super(v);
        name = (TextView) v.findViewById(R.id.name);
        city = (TextView) v.findViewById(R.id.city);
        uni = (TextView) v.findViewById(R.id.university);

     }


   }

   }

这是我的适配器类，上面是我的Home活动，我试图显示我的列表

Answer 1

我认为问题在于您尝试将适配器设置在主线程之外。你应该使用这段代码：

 @Override
    public void processData(JSONArray data)
    {

        JSONObject js;

                if(data!=null)
                {
                     info=new ArrayList<>();

                    try
                    {
                        for(int i=0;i<data.length();i++)
                        {
                            js =data.getJSONObject(i);
                            info in=new info(js.getString("Names"),js.getString("city"),js.getString("university"));
                            info.add( in);




                        }


   runOnUiThread(new Runnable() {

        @Override
        public void run() {
            myadaptor=new Adaptor(info);

                            recyclerView.addItemDecoration(new DividerItemDecoration(this, LinearLayoutManager.VERTICAL));
                            LinearLayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
                            recyclerView.setLayoutManager(mLayoutManager);
                            recyclerView.setItemAnimator(new DefaultItemAnimator());
                            recyclerView.setAdapter( myadaptor);
           }
        });

Answer 2

尝试在onCreate中初始化适配器，recyclerview和layoutmanager。然后当你在processData中调用完成后获取列表并调用mAdapter.notifyDataSetChanged。

public class Home extends AppCompatActivity implements HomeCallBack {

public ArrayList<info> info;
private  Adaptor myadaptor;
private RecyclerView recyclerView;
private RecyclerView.LayoutManager layoutManager;

@Override
 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home);
    recyclerView=(RecyclerView)findViewById(R.id.recycle_view);
    info = new ArrayList<>();
    myadaptor=new Adaptor(info);
    recyclerView.addItemDecoration(new DividerItemDecoration(this, LinearLayoutManager.VERTICAL));
    LinearLayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
    recyclerView.setLayoutManager(mLayoutManager);
    recyclerView.setItemAnimator(new DefaultItemAnimator());
    recyclerView.setAdapter(myadaptor);

    BackgroundHome backgroundHome=new BackgroundHome(this,this);
    backgroundHome.execute();
}

@Override
public void processData(JSONArray data) {
    JSONObject js;
            if(data!=null) {
                try {
                    for(int i=0; i<data.length(); i++)
                    {
                        js = data.getJSONObject(i);
                        info in = new info(js.getString("Names"),js.getString("city"),js.getString("university"));
                        info.add(in);
                    }

                    myadaptor.notifyDataSetChanged();

在recyclerView中没有附加适配器

2 个答案: