Question

这是我第一次使用回收视图，我添加了适配器类，并且所有代码都没有错误，但没有任何显示。我根据这篇帖子Simple Android RecyclerView example中的第一个答案做了所有事情，但仍然有一些地方我做错了，我也不知道在哪里寻找。在运行日志中，我发现了此错误

Caused by: java.lang.ClassNotFoundException: Didn't find class "android.view.View$OnUnhandledKeyEventListener" on path: DexPathList

但是我尝试使用在线查找的内容修复它，但仍然无法正常工作

    package com.mircea.bookapp;

import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;
import java.util.List;

public class BookActivity extends AppCompatActivity implements BookListViewAdapter.ItemClickListener {


    BookListViewAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_book);


        //Hardcoded books
        List<Book> books = new ArrayList<>();
        books.add(new Book(" In Search of Lost Time", "Marcel Proust", 1913, "modernist"));
        books.add(new Book(" In Search of Lost Time", "Marcel Proust", 1913, "modernist"));
        books.add(new Book(" In Search of Lost Time", "Marcel Proust", 1913, "modernist"));
        books.add(new Book(" In Search of Lost Time", "Marcel Proust", 1913, "modernist"));
        books.add(new Book(" In Search of Lost Time", "Marcel Proust", 1913, "modernist"));

        // set up the RecyclerView
        RecyclerView recyclerView = findViewById(R.id.booklist);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        adapter = new BookListViewAdapter(this, books);
        adapter.setClickListener(this);
        recyclerView.setAdapter(adapter);

    }

    @Override
    public void onItemClick(View view, int position) {
        Toast.makeText(this, "You clicked " + adapter.getItem(position) + " on row number " + position, Toast.LENGTH_SHORT).show();

    }
}

我在做什么错？这也是BookListViewAdapter类的代码

package com.mircea.bookapp;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.List;

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

    private List<Book> mData;
    private LayoutInflater mInflater;
    private ItemClickListener mClickListener;

    // data is passed into the constructor
    BookListViewAdapter(Context context, List<Book> data) {
        this.mInflater = LayoutInflater.from(context);
        this.mData = data;
    }

    // parent activity will implement this method to respond to click events
    public interface ItemClickListener {
        void onItemClick(View view, int position);
    }


    // inflates the row layout from xml when needed
    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = mInflater.inflate(R.layout.recyclerview_row, parent, false);
        return new ViewHolder(view);
    }

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

    }

    @Override
    public int getItemCount() {
        return mData.size();
    }
    // convenience method for getting data at click position
    Book getItem(int id) {
        return mData.get(id);
    }

    // allows clicks events to be caught
    void setClickListener(ItemClickListener itemClickListener) {
        this.mClickListener = itemClickListener;
    }

    // stores and recycles views as they are scrolled off screen
    public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
        TextView myTextView;

        ViewHolder(View itemView) {
            super(itemView);
            myTextView = itemView.findViewById(R.id.bookTitle);
            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View v) {

        }
    }


}

Answer 1

您需要在onBindViewHolder中设置setText

@Override
    public void onBindViewHolder(@NonNull BookListViewAdapter.ViewHolder holder, int position) {
        holder. myTextView.setText()//the text you want 
    }

Answer 2

我认为问题是您忘记添加ArrayList。尝试将其与您的RecyclerView设置代码一起添加。

   RecyclerView recyclerView = findViewById(R.id.booklist);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));
// Add ArrayList here
    adapter = new BookListViewAdapter(this, books);
    adapter.setClickListener(this);
    recyclerView.setAdapter(adapter);

RecycleView不显示任何项目

2 个答案: