Question

我在RecyclerView中使用Android，model class使用title和details。什么都没有显示出来。即使在log内Adapter Android Monitor之后，public ArrayList<Menu> menu_list; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main_menu); initUi(); } public void initUi(){ RecyclerView menu_recycler = (RecyclerView) findViewById(R.id.main_menu_recycler_view); //set the layout manager LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this); linearLayoutManager.setOrientation( linearLayoutManager.VERTICAL ); menu_recycler.setLayoutManager( linearLayoutManager ); //set adapter MainMenuAdapter mainMenuAdapter = new MainMenuAdapter( getMenulist() ); menu_recycler.setAdapter( mainMenuAdapter ); } public ArrayList<Menu> getMenulist() { menu_list = new ArrayList<Menu>(); menu_list.add( new Menu("About Us", " Learn more about our values, mission and vision ") ); menu_list.add( new Menu("Services ", " In implementing its mandate, the Agency will provide the following to its external and internal customers:\n")); menu_list.add( new Menu("Stakeholders", " Who are the key players, Find out more") ); menu_list.add( new Menu("Learn about Counterfeits", "Gain more insight on counterfeit products")); return menu_list; }也没有显示任何内容。

MainActivity.class

public class MainMenuAdapter extends RecyclerView.Adapter<MainMenuAdapter.MyViewHolder> {

    public List<Menu> list_of_menus;

    public MainMenuAdapter( List<Menu> list_of_menus){
        this.list_of_menus = list_of_menus;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.row,parent, false);
        return new MyViewHolder(v);
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        Menu menu = list_of_menus.get(position);
        Log.e("MENU IN ADAPTER TITLE", menu.title);
        holder.title_text.setText( menu.title );
        holder.details_text.setText( menu.details );

    }


    @Override
    public int getItemCount() {
        return 0;
    }

    /*
      View Holder class
    * */

    public class MyViewHolder extends RecyclerView.ViewHolder{
        public TextView title_text, details_text;

        public MyViewHolder(View itemView) {
            super(itemView);
            title_text = (TextView) itemView.findViewById(R.id.menu_title);
            details_text = (TextView) itemView.findViewById(R.id.menu_details);
        }
    }   

}

，这是我的适配器

public class Menu {
    public String title, details;

    public Menu(String title, String details){
        this.details = details;
        this.title = title;
    }

}

和模型类

main_activity

布局文件<?xml version="1.0" encoding="utf-8"?> <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.maos.aca.MainMenuActivity"> <android.support.v7.widget.RecyclerView android:layout_width="334dp" android:layout_height="453dp" app:layout_constraintTop_toTopOf="parent" android:layout_marginTop="8dp" app:layout_constraintBottom_toBottomOf="parent" android:layout_marginBottom="8dp" android:layout_marginLeft="8dp" app:layout_constraintLeft_toLeftOf="parent" android:layout_marginRight="8dp" app:layout_constraintRight_toRightOf="parent" android:id="@+id/main_menu_recycler_view" android:scrollbars="vertical"/> </android.support.constraint.ConstraintLayout>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical" android:layout_width="wrap_content"
              android:layout_height="wrap_content">

    <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/menu_title"
            android:textStyle="bold"
    />
    <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/app_name"
            android:id="@+id/menu_details"/>
</LinearLayout>

最后一行

{{1}}

我知道之前已经问过这个问题，但没有一个答案帮助我。我会感激任何领导。

Answer 1

您需要将getItemCount()方法更改为：

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

如果您报告的尺寸为零，RecyclerView将不会显示任何元素。

Answer 2

改变这个：

   @Override
   public int getItemCount() {
        return 0;
   }

对此：

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

RecyclerView不显示项目

2 个答案: