我的RecyclerView不调用onCreateViewHolder, onBindViewHolder甚至MenuViewHolder构造函数,因此什么也没有出现在RecyclerView。 我放置了用于调试的日志,但没有显示日志。 有什么问题吗?

我的适配器:

public class MenuAdapter extends RecyclerView.Adapter<MenuAdapter.MenuViewHolder> {
private LayoutInflater inflater;
List<Menu> data = Collections.emptyList();

public MenuAdapter(Context context, List<Menu> data) {
    Log.i("DEBUG", "Constructor");
    inflater = LayoutInflater.from(context);
    Log.i("DEBUG MENU - CONSTRUCTOR", inflater.toString());
    this.data = data;
    for(Menu menu: this.data){
        Log.i("DEBUG MENU - CONSTRUCTOR", menu.menu);
    }
}

@Override
public MenuViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = inflater.inflate(R.layout.row_menu, parent, false);
    MenuViewHolder holder = new MenuViewHolder(view);
    return holder;
}

@Override
public void onBindViewHolder(MenuViewHolder holder, int position) {
    Log.i("DEBUG MENU", "onBindViewHolder");
    Menu current = data.get(position);
    holder.title.setText(current.menu);
}

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

class MenuViewHolder extends RecyclerView.ViewHolder {
    TextView title;
    ImageView icon;

    public MenuViewHolder(View itemView) {
        super(itemView);
        title = (TextView) itemView.findViewById(R.id.menuText);
    }
}

我的自定义行XML:

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

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/menuText"
    android:text="Dummy Text"
    android:layout_gravity="center_vertical"
    android:textColor="#222"/>

和我的碎片:

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

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mUserLearnedDrawer = Boolean.valueOf(readFromPreferences(getActivity(), KEY_USER_LEARNED_DRAWER, "false"));
    if (savedInstanceState != null) {
        mFromSavedInstaceState = true;
    }
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment

    View view = inflater.inflate(R.layout.fragment_navigation, container, false);
    RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.drawer_list);
    MenuAdapter adapter = new MenuAdapter(getActivity(), getData());
    recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
    recyclerView.setAdapter(adapter);
    return view;
}

当前回答

我忘记在下面添加,我添加后,它为我工作

recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

其他回答

我真的真的希望有一天这能帮助到别人。我花了一个多小时在这上面都快疯了!

我有这个:

projects_recycler_view.apply {
            this.layoutManager = linearLayoutManager
            this.adapter = adapter
        }

当我本该拥有这些的时候:

projects_recycler_view.apply {
            this.layoutManager = linearLayoutManager
            this.adapter = projectAdapter
        }

因为我愚蠢地调用了我的适配器适配器,它被应用块中的回收器视图的适配器遮蔽了!我将适配器重命名为projectAdapter以区分它,问题解决了!

您忘记了xml中的这一行 应用:layoutManager = " androidx.recyclerview.widget.LinearLayoutManager "

or

    app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"

不是主帖里的情况,但对某些人来说可能会派上用场。 如果设置setHasStableIds(true);,则覆盖getItemId(position)是适配器。

在我的情况下,我错过了在适配器中设置列表后调用notifyDataSetChanged()。

public void setUserList(List<UserList> userList) {
      this.userList = userList;
        notifyDataSetChanged();
}

在我的情况下,在改变活动使用ViewModel和DataBinding后,我忘记从onCreate方法中删除setContentView方法调用。把它拿走,我的问题就解决了。