一窃祝、先檢查適配器#####

查看適配器是否有誤，
檢查getItemCount()方法中是否 return data.size();

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {
    private List<String> data = new ArrayList<>();
    private Context context;
    private LayoutInflater inflater;

    public RecyclerViewAdapter(Context context, List<String> data) {
        this.data = data;
        this.context = context;
        inflater=LayoutInflater.from(context);
    }


    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = inflater.inflate(R.layout.recycler_view_item,null);
        ViewHolder   viewHolder = new ViewHolder(view);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.tv.setText(data.get(position));
    }

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

    class ViewHolder extends RecyclerView.ViewHolder {

        TextView tv;

        public ViewHolder(View view) {
            super(view);
            tv=(TextView) view.findViewById(R.id.tv_item);
        }

    }
}

二滋觉、無數(shù)據(jù)#####

啟動發(fā)現(xiàn)有錯包晰，指向adapter中的getItemCount()方法，并報了一個空指針異常演侯，說明沒有數(shù)據(jù)

           java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
                                                   at wapchief.top.retrofitrxjavatest.RecyclerViewAdapter.getItemCount(RecyclerViewAdapter.java:47)

三姿染、布局管理器配置#####

在onCreate方法中實現(xiàn)：

        //數(shù)據(jù)源
        datas();
        adapter=new RecyclerViewAdapter(this,data);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setAdapter(adapter);

四、onCreate方法#####

對比兩種方法秒际，
如果在onCreate（Bundle savedInstanceState, PersistableBundle persistentState）中使用
需要在AndroidManifest.xml文件下Activity中注冊權(quán)限：

<activity android:name=".RecyclerViewActivity"
      android:persistableMode="persistAcrossReboots"/>

在onCreate(Bundle savedInstanceState)中則不需要

@Override
    public void onCreate(Bundle savedInstanceState, PersistableBundle persistentState) {
        super.onCreate(savedInstanceState, persistentState);
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);