帶有 RecyclerView 的片段，沒有適配器附加錯誤

Question

我正在用不同的片段制作一個選項卡式活動，其中一個包含一個 recyclerview，目前只有一些名字。 我不知道我做錯了什么，每次啟動應用程序時都會收到一條警告，提示沒有附加適配器，跳過布局。 我已經在我的片段中創建了適配器並將其設置為 recyclerview，創建了一個帶有 viewholder 的適配器，並創建了一個 class 來設置 recyclerview 上的名稱。

這是我的片段 class：

public class fragment_main extends Fragment {

    View view;
    private RecyclerView mainrecyclerview;
    private List<MainSchedule> listStr;

    public fragment_main() {}

    @NonNull
    @Override
    public View onCreateView(LayoutInflater inflater, @NonNull ViewGroup container, @NonNull Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.fragment_main, container, false);
        mainrecyclerview = (RecyclerView) view.findViewById(R.id.todayRecyclerView);
        MainRecyclerViewAdapter mainAdapter = new MainRecyclerViewAdapter(getActivity(), listStr);
        mainrecyclerview.setLayoutManager(new LinearLayoutManager(getActivity()));
        mainrecyclerview.setAdapter(mainAdapter);
        return super.onCreateView(inflater, container, savedInstanceState);
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        listStr = new ArrayList<>();
        listStr.add(new MainSchedule("one"));
        listStr.add(new MainSchedule("two"));
        listStr.add(new MainSchedule("three"));

    }
}

片段.xml：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".fragment_main">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/todayRecyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginStart="32dp"
        android:layout_marginTop="24dp"
        android:layout_marginEnd="32dp"
        android:layout_marginBottom="250dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

回收器視圖適配器 class：

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

    Context mContext;
    List<MainSchedule> mData;

    public MainRecyclerViewAdapter(Context context, List<MainSchedule> data){
        this.mContext = context;
        this.mData = data;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(mContext).inflate(R.layout.mainschedule_cards, parent, false);
        return new ViewHolder(view);
    }

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

        holder.textView.setText(mData.get(position).getName());

    }

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

    public static class ViewHolder extends RecyclerView.ViewHolder {

        private TextView textView;

        public ViewHolder(View itemView) {
            super(itemView);
            textView = (TextView) itemView.findViewById(R.id.textViewClass);
        }

    }

}

我已經嘗試了很多方法來創建適配器並將布局管理器綁定到 recyclerview，但似乎沒有任何效果，而且我每次都遇到相同的錯誤。

Answer 1

onCreateView似乎有問題，因為您應該返回視圖

用下面的代碼替換你的fragment_main

public class fragment_main extends Fragment {

    private RecyclerView mainrecyclerview;
    private List<MainSchedule> listStr;

    public fragment_main() {
    }

    @NonNull
    @Override
    public View onCreateView(LayoutInflater inflater, @NonNull ViewGroup container, @NonNull Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_main, container, false);
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        listStr = new ArrayList<>();
        listStr.add(new MainSchedule("one"));
        listStr.add(new MainSchedule("two"));
        listStr.add(new MainSchedule("three"));
        mainrecyclerview = (RecyclerView) view.findViewById(R.id.todayRecyclerView);
        MainRecyclerViewAdapter mainAdapter = new MainRecyclerViewAdapter(getActivity(), listStr);
        mainrecyclerview.setLayoutManager(new LinearLayoutManager(getActivity()));
        mainrecyclerview.setAdapter(mainAdapter);
    }
}