Android控件 RecyclerView基本使用/常见问题

3Blue1Red

已于 2022-09-29 18:54:30 修改

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分类专栏： #Android 笔记文章标签： android

于 2020-12-25 14:19:56 首次发布

本文链接：https://blog.youkuaiyun.com/Blue3Red1/article/details/111673092

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本文围绕 Android 的 RecyclerView 展开，介绍了其准备工作、配置 Adapter 内部方法、显示数据、切换布局、添加点击事件、增加或删除 Item、配置动画等操作步骤，还给出了所有代码预览。同时，针对 RecyclerViewAdapter 获取数据时空指针异常、加载图片卡顿、item 无法居中显示等常见问题进行了原因分析和解决方法说明。

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RecyclerView 很强大很好用，直接开整。

一、RecyclerView 准备工作

Gradle 中引入 dependencies 闭包

dependencies {
	implementation 'androidx.recyclerview:recyclerview:1.1.0'
}

修改 activity_main.xml，配置按键和 RecyclerView 控件 layout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="添加数据"
        android:onClick="onAddDataClick"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="切换布局"
        android:onClick="onChangeLayoutClick"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="插入一条数据"
        android:onClick="onInsertDataClick"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="删除一条数据"
        android:onClick="onRemoveDataClick"/>
    
    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        </androidx.recyclerview.widget.RecyclerView>

</LinearLayout>

新建一个类继承 RecyclerView.Adapter
并且创建一个内部类 MyViewHolder 传入 RecyclerView.Adapter 泛型
重写 MyRecyclerViewAdapter 抽象方法

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

	public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return null;
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder,final int position) {
    
    }

    @Override
    public int getItemCount() {
    }
    
	//创建一个MyViewHolder继承RecyclerView.ViewHolder
    class MyViewHolder extends RecyclerView.ViewHolder {
    
        public MyViewHolder(@NonNull View itemView) {
            super(itemView);
        }
    }
}

二、配置 Adapter 内部方法

新建一个 layout_item.xml 用于作 Adapter 的 item

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="5dp"
    android:background="#A4D3EE">

    <ImageView
        android:id="@+id/image_view"
        android:layout_width="88dp"
        android:layout_height="88dp"
        android:scaleType="fitXY"
        />

    <TextView
        android:id="@+id/text_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:textSize="22sp"
        android:textColor="#FFF"
        android:gravity="center"
        android:layout_marginStart="8dp"/>

</LinearLayout>

加载布局，创建一个 ViewHolder

	//创建并且返回 ViewHolder
	@NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        //创建layout.layout_item，绑定View，返回ViewHolder给onBindViewHolder
        View view = LayoutInflater.from(mContext).inflate(R.layout.layout_item,
                parent, false);
        MyViewHolder holder = new MyViewHolder(view);
        return holder;
    }

从 ViewHolder 中 findViewById

	//创建一个MyViewHolder继承RecyclerView.ViewHolder
    class MyViewHolder extends RecyclerView.ViewHolder {

        TextView textView;
        ImageView imageView;

        //这里提出MyViewHolder中的View来做点击事件处理
        View itemView;

        //onCreateViewHolder中创建MyViewHolder对象，传入View
        public MyViewHolder(@NonNull View itemView) {
            super(itemView);
            imageView = itemView.findViewById(R.id.image_view);
            textView = itemView.findViewById(R.id.text_view);
            this.itemView = itemView;
        }
    }

绑定数据

	//绑定数据
    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder,final int position) {
        //4.通过onCreateViewHolder传来的ViewHolder来进行数据源设置
        holder.textView.setText(dataSource.get(position));
        holder.imageView.setImageResource(getIcon(position));
    }

创建数据源

注意：一定要初始化数据源，否则getItemCount会出现空指针

    private final Context mContext;
    private List<String> dataSource;
    
	//或者layout_item布局设置为vertical，然后随机textView字符串的长度
    public MyRecyclerViewAdapter(Context context) {
        //初始化数据源，否则getItemCount会出现空指针
        this.dataSource = new ArrayList<>();
        this.mContext = context;
    }

	//设置数据源
    public void setDataSource(List<String> dataSource) {
        this.dataSource = dataSource;
        notifyDataSetChanged();
    }

	//这里使用自定义的五张图片循环使用
	private int getIcon (int position) {
        switch (position % 5) {
            case 0:
                return R.mipmap.a;
            case 1:
                return R.mipmap.b;
            case 2:
                return R.mipmap.c;
            case 3:
                return R.mipmap.d;
            case 4:
                return R.mipmap.e;
        }
        return 0;
    }

返回数据量

	//返回数据量
    @Override
    public int getItemCount() {
        //5.返回数据总量
        return dataSource.size();
    }

三、显示数据

MainActivity 中给 RecyclerView 配置 Adapter

public class MainActivity extends AppCompatActivity {

    private RecyclerView mRecyclerView;
    private MyRecyclerViewAdapter mAdapter;
    private List<String> mDataSource = new ArrayList<>();

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

        mRecyclerView = findViewById(R.id.recycler_view);

        //LayoutManager用于指定RecyclerView的布局方式
        //LinearLayoutManager为线性布局
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);

        //设置RecyclerView的布局
        mRecyclerView.setLayoutManager(linearLayoutManager);

        mAdapter = new MyRecyclerViewAdapter(this);
        mRecyclerView.setAdapter(mAdapter);
    }

    //使用按键创建并设置数据源
    public void onAddDataClick(View view) {
        for (int i = 0; i < 20; i++) {
            String s = "第" + i + "条数据";
            mDataSource.add(s);
        }
        mAdapter.setDataSource(mDataSource);
    }
}

横向显示数据，需要在加载 Adapter 之前配置 linearLayoutManager

		...
		//横向排列ItemView，最好修改layout_item为vertical
        linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
        //数据反向展示（从右向左滑动）
        linearLayoutManager.setReverseLayout(true);
        ...

运行结果

四、切换布局

RecyclerView 除了 LinearLayout 外，还有 GridLayout 网格布局和 StaggeredGridLayout 瀑布流布局
修改 MyRecyclerViewAdapter 构造方法，新增传入mRecyclerView用来设置textView随机高度

	private RecyclerView mRecyclerView;
	//参数2 传入mRecyclerView用来设置textView随机高度；
    //或者layout_item布局设置为vertical，然后随机textView字符串的长度
    public MyRecyclerViewAdapter(Context context, RecyclerView mRecyclerView) {
        //初始化数据源，否则getItemCount会出现空指针
        this.dataSource = new ArrayList<>();
        this.mContext = context;
        this.mRecyclerView = mRecyclerView;
    }

随机控件高度

	//获取TextView随机高度
    private int getRandomHeight() {
        return (int)(Math.random() * 1000);
    }

在 onBindViewHolder 方法增加条件判断

	@Override
    public void onBindViewHolder(@NonNull MyViewHolder holder,final int position) {
		...
        //如果是瀑布流就设置随机高度
        if (mRecyclerView.getLayoutManager().getClass() == StaggeredGridLayoutManager.class) {
            LinearLayout.LayoutParams params
                    = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, getRandomHeight());
            holder.textView.setLayoutParams(params);
        } else {
            LinearLayout.LayoutParams params
                    = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
            holder.textView.setLayoutParams(params);
        }
    }

修改 MainActivity 中的方法

	protected void onCreate(Bundle savedInstanceState) {
		...
		//onCreate方法中修改
		mAdapter = new MyRecyclerViewAdapter(this, mRecyclerView);
		...
	}

	//改变mAdapter的布局方式
    public void onChangeLayoutClick(View view) {
        //从线性布局 --> 网格布局
        if (mRecyclerView.getLayoutManager().getClass() == LinearLayoutManager.class) {
            GridLayoutManager gridLayoutManager = new GridLayoutManager(this, 2);
            mRecyclerView.setLayoutManager(gridLayoutManager);
        }
        //网格布局 --> 瀑布流布局
        else if (mRecyclerView.getLayoutManager().getClass() == GridLayoutManager.class) {
            StaggeredGridLayoutManager staggeredGridLayoutManager
                    = new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL);
            mRecyclerView.setLayoutManager(staggeredGridLayoutManager);
        }
        //瀑布流布局 --> 线性布局
        else if (mRecyclerView.getLayoutManager().getClass() == StaggeredGridLayoutManager.class) {
            LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
            mRecyclerView.setLayoutManager(linearLayoutManager);
        }
    }

五、添加点击事件

MyRecyclerViewAdapter 中创建 ItemView 点击事件回调接口

public class MyRecyclerViewAdapter extends 
				RecyclerView.Adapter<MyRecyclerViewAdapter.MyViewHolder> {
	private OnItemClickListener onItemClickListener;
    private OnImageClickListener onImageClickListener;
    
	...
	
	//ItemView点击事件回调接口
    interface OnItemClickListener {
        void onItemClick(int position);
    }

    interface OnImageClickListener {
        void onItemClick(int position);
    }

    public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
        this.onItemClickListener = onItemClickListener;
    }

    public void setOnImageClickListener(OnImageClickListener onImageClickListener) {
        this.onImageClickListener = onImageClickListener;
    }
}

在 onBindViewHolder 中使用回调方法

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder,final int position) {
    
		...
		
        //点击事件处理
        holder.itemView.setOnClickListener(v -> {
            if (onItemClickListener != null) {
                //这里使用回调方法，具体怎么使用还得从MainActivity中重写
                onItemClickListener.onItemClick(position);
            }
        });

        holder.imageView.setOnClickListener(v -> {
            if (onImageClickListener != null) {
                //这里使用回调方法，具体怎么使用还得从MainActivity中重写
                onImageClickListener.onItemClick(position);
            }
        });
    }

或者在 onCreateViewHolder 中使用回调方法

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        //创建layout.layout_item，绑定View，返回ViewHolder给onBindViewHolder
        View view = LayoutInflater.from(mContext).inflate(R.layout.layout_item,
                parent, false);
        MyViewHolder holder = new MyViewHolder(view);

        //onClick方法写在onCreateViewHolder中
        holder.imageView.setOnClickListener(v -> {
            int position = holder.getAdapterPosition();
            if (onItemClickListener != null) {
                //这里使用回调方法，具体怎么使用还得从MainActivity中重写
                onItemClickListener.onItemClick(position);
            }
        });
        return holder;
    }

MainActivity 重写回调方法

	@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        ...
        
        mAdapter.setOnItemClickListener(position -> {
			Toast.makeText(MainActivity.this, "第" + position + "数据被点击", Toast.LENGTH_SHORT).show();
        });
        
        mAdapter.setOnImageClickListener(position -> {
            Toast.makeText(MainActivity.this, "第" + position + "图片被点击", Toast.LENGTH_SHORT).show();
        });
    }

六、增加 \ 删除 Item

MyRecyclerViewAdapter 中增加方法

//添加的数据位置，用来改变新加数据的背景色
    private int addDataPosition = -1;
    
    //添加一条数据
    public void addData(int position) {
        addDataPosition = position;
        dataSource.add(position, "添加的数据");
        //通知插入数据
        notifyItemInserted(position);
        //通知数据长度变更
        // 参数1：是起始位置，从哪里开始更新，参数2：更新的总数
        notifyItemRangeChanged(position, dataSource.size() - position);
        //添加数据时滚动到第一行
        mRecyclerView.smoothScrollToPosition(position);
    }

    //删除一条数据
    public void deleteData(int position){
        addDataPosition = -1;
        dataSource.remove(position);
        //通知插入数据
        notifyItemRemoved(position);
        //通知数据长度变更
        // 参数1：是起始位置，从哪里开始更新，参数2：更新的总数
        notifyItemRangeChanged(position, dataSource.size() - position);
    }

修改 onBindViewHolder 中的代码

	public void onBindViewHolder(@NonNull MyViewHolder holder,final int position) {
		...
        //改变新添加的颜色
        if (addDataPosition == position) {
            holder.itemView.setBackgroundColor(Color.RED);
        } else {
            holder.itemView.setBackgroundColor(Color.parseColor("#A4D3EE"));
        }
    }

MainActivity 中增加方法

	public void onRemoveDataClick(View view) {
        mAdapter.deleteData(0);
    }

    public void onInsertDataClick(View view) {
        mAdapter.addData(0);
    }

在这里插入图片描述

七、配置动画 setItemAnimator

可以参考学习：
https://www.jianshu.com/p/2a82b0341138

八、所有代码预览

MyRecyclerViewAdapter

/**
 * 1、继承RecyclerView.Adapter
 * 2、绑定ViewHolder
 * 3、实现Adapter的相关方法
 */
public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.MyViewHolder> {

    private final Context mContext;
    private List<String> dataSource;
    private RecyclerView mRecyclerView;

    private OnItemClickListener onItemClickListener;
    private OnImageClickListener onImageClickListener;

    //添加的数据位置，用来改变新加数据的背景色
    private int addDataPosition = -1;

    //参数2 传入mRecyclerView用来设置textView随机高度；
    //或者layout_item布局设置为vertical，然后随机textView字符串的长度
    public MyRecyclerViewAdapter(Context context, RecyclerView mRecyclerView) {
        //初始化数据源，否则getItemCount会出现空指针
        this.dataSource = new ArrayList<>();
        this.mContext = context;
        this.mRecyclerView = mRecyclerView;
    }

    //设置数据源
    public void setDataSource(List<String> dataSource) {
        this.dataSource = dataSource;
        notifyDataSetChanged();
    }

    //获取图片数据
    private int getIcon (int position) {
        switch (position % 5) {
            case 0:
                return R.mipmap.a;
            case 1:
                return R.mipmap.b;
            case 2:
                return R.mipmap.c;
            case 3:
                return R.mipmap.d;
            case 4:
                return R.mipmap.e;
        }
        return 0;
    }

    //获取TextView随机高度
    private int getRandomHeight() {
        return (int)(Math.random() * 1000);
    }

    //创建并且返回 ViewHolder
    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        //2.创建layout.layout_item，绑定View，返回ViewHolder给onBindViewHolder
        View view = LayoutInflater.from(mContext).inflate(R.layout.layout_item,
                parent, false);
        MyViewHolder holder = new MyViewHolder(view);

        //7.onClick方法写在onCreateViewHolder中
//        holder.imageView.setOnClickListener(v -> {
//            int position = holder.getAdapterPosition();
//            if (onItemClickListener != null) {
//                //这里使用回调方法，具体怎么使用还得从MainActivity中重写
//                onItemClickListener.onItemClick(position);
//            }
//        });
        return holder;
    }
    
    //绑定数据
    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder,final int position) {
        //4.通过onCreateViewHolder传来的ViewHolder来进行数据源设置
        holder.textView.setText(dataSource.get(position));
        holder.imageView.setImageResource(getIcon(position));

        //8.改变新添加的颜色
        if (addDataPosition == position) {

            holder.itemView.setBackgroundColor(Color.RED);
        } else {
            holder.itemView.setBackgroundColor(Color.parseColor("#A4D3EE"));
        }
        
        //6.如果是瀑布流就设置随机高度
        if (mRecyclerView.getLayoutManager().getClass() == StaggeredGridLayoutManager.class) {
            LinearLayout.LayoutParams params
                    = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, getRandomHeight());
            holder.textView.setLayoutParams(params);
        } else {
            LinearLayout.LayoutParams params
                    = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
            holder.textView.setLayoutParams(params);
        }
        
        //7.点击事件处理
        holder.itemView.setOnClickListener(v -> {
            if (onItemClickListener != null) {
                //这里使用回调方法，具体怎么使用还得从MainActivity中重写
                onItemClickListener.onItemClick(position);
            }
        });

        holder.imageView.setOnClickListener(v -> {
            if (onImageClickListener != null) {
                //这里使用回调方法，具体怎么使用还得从MainActivity中重写
                onImageClickListener.onItemClick(position);
            }
        });

    }

    //返回数据量
    @Override
    public int getItemCount() {
        //5.返回数据总量
        return dataSource.size();
    }

    //1.创建一个MyViewHolder继承RecyclerView.ViewHolder
    class MyViewHolder extends RecyclerView.ViewHolder {

        TextView textView;
        ImageView imageView;

        //7.这里提出MyViewHolder中的View来做点击事件处理
        View itemView;

        //3.onCreateViewHolder中创建MyViewHolder对象，传入View
        public MyViewHolder(@NonNull View itemView) {
            super(itemView);
            imageView = itemView.findViewById(R.id.image_view);
            textView = itemView.findViewById(R.id.text_view);
            this.itemView = itemView;
        }
    }

    //7.ItemView点击事件回调接口
    interface OnItemClickListener {
        void onItemClick(int position);
    }

    interface OnImageClickListener {
        void onItemClick(int position);
    }

    public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
        this.onItemClickListener = onItemClickListener;
    }

    public void setOnImageClickListener(OnImageClickListener onImageClickListener) {
        this.onImageClickListener = onImageClickListener;
    }

    //8.添加一条数据
    public void addData(int position) {
        addDataPosition = position;
        dataSource.add(position, "添加的数据");
        //通知插入数据
        notifyItemInserted(position);
        //通知数据长度变更
        // 参数1：是起始位置，从哪里开始更新，参数2：更新的总数
        notifyItemRangeChanged(position, dataSource.size() - position);
        mRecyclerView.smoothScrollToPosition(position);
    }

    //8.删除一条数据
    public void deleteData(int position){
        addDataPosition = -1;
        dataSource.remove(position);
        //通知插入数据
        notifyItemRemoved(position);
        //通知数据长度变更
        // 参数1：是起始位置，从哪里开始更新，参数2：更新的总数
        notifyItemRangeChanged(position, dataSource.size() - position);
    }
}

MainActivity

public class MainActivity extends AppCompatActivity {

    private RecyclerView mRecyclerView;
    private MyRecyclerViewAdapter mAdapter;
    private List<String> mDataSource = new ArrayList<>();

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

        mRecyclerView = findViewById(R.id.recycler_view);

        //LayoutManager用于指定RecyclerView的布局方式
        //LinearLayoutManager为线性布局
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);

        //横向排列ItemView，最好修改layout_item为vertical
        //linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
        //数据反向展示
        //linearLayoutManager.setReverseLayout(true);

        //设置RecyclerView的布局
        mRecyclerView.setLayoutManager(linearLayoutManager);

        mAdapter = new MyRecyclerViewAdapter(this, mRecyclerView);
        mRecyclerView.setAdapter(mAdapter);

        //mRecyclerView.setItemAnimator(new DefaultItemAnimator());

//        mAdapter.setOnItemClickListener(position -> {
//            Toast.makeText(MainActivity.this, "第" + position + "数据被点击", Toast.LENGTH_SHORT).show();
//        });

        mAdapter.setOnImageClickListener(position -> {
            Toast.makeText(MainActivity.this, "第" + position + "图片被点击", Toast.LENGTH_SHORT).show();
        });
    }

    public void onRemoveDataClick(View view) {
        mAdapter.deleteData(0);
    }

    public void onInsertDataClick(View view) {
        mAdapter.addData(0);
    }

    //改变mAdapter的布局方式
    public void onChangeLayoutClick(View view) {
        //从线性布局 --> 网格布局
        if (mRecyclerView.getLayoutManager().getClass() == LinearLayoutManager.class) {
            GridLayoutManager gridLayoutManager = new GridLayoutManager(this, 2);
            mRecyclerView.setLayoutManager(gridLayoutManager);
        }
        //网格布局 --> 瀑布流布局
        else if (mRecyclerView.getLayoutManager().getClass() == GridLayoutManager.class) {
            StaggeredGridLayoutManager staggeredGridLayoutManager
                    = new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL);
            mRecyclerView.setLayoutManager(staggeredGridLayoutManager);
        }
        //瀑布流布局 --> 线性布局
        else if (mRecyclerView.getLayoutManager().getClass() == StaggeredGridLayoutManager.class) {
            LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
            mRecyclerView.setLayoutManager(linearLayoutManager);
        }
    }

    //创建并设置数据源
    public void onAddDataClick(View view) {
        for (int i = 0; i < 20; i++) {
            String s = "第" + i + "条数据";
            mDataSource.add(s);
        }
        mAdapter.setDataSource(mDataSource);
    }
}

常见问题：

1. RecyclerViewAdapter 获取数据的时候空指针异常 java.lang.NullPointerException.

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

原因分析：

设置数据之前需要初始化数据
网络请求的数据需要在完成后加载 Adapter

解决方法：

public MyRecyclerViewAdapter(Context context) {
    //初始化数据源，否则getItemCount会出现空指针
    this.dataSource = new ArrayList<>();
    this.mContext = context;
}

api.getAll().enqueue(new Callback<Result>() {
    @Override
    public void onResponse(Call<Result> call, Response<Result> response) {
        Result result = response.body();

        MovieAdapter adapter = new MovieAdapter(result);
        mainBinding.rvList.setLayoutManager(new GridLayoutManager(MainActivity.this, 2));
        mainBinding.rvList.setAdapter(adapter);
    }

    @Override
    public void onFailure(Call<Result> call, Throwable t) {
        Toast.makeText(MainActivity.this, "网络错误", Toast.LENGTH_SHORT).show();
    }
});

2. RecyclerViewAdapter 加载图片卡顿严重

RecyclerView 滑动的时候在加载图片卡顿非常明显

public void bindMovieImg(String s) {
    Glide.with(doubleItemBinding.getRoot().getContext())
            .load(s)
            .into(doubleItemBinding.ivMovieImg);
}

原因分析：

ImageView 不要使用裁切，直接填充。
glide 缓存的图片问题

解决方法：

android:scaleType 使用填充 ImageView 的大小，免去加载图片的时候还要裁切。

<ImageView
    android:id="@+id/iv_movie_img"
    android:layout_width="170dp"
    android:layout_height="220dp"
    android:scaleType="fitXY"
    tools:src="@mipmap/p2455261804" />

3. RecyclerView 中的 item 无法居中显示

原因分析：

RecyclerView 中的 layout_width 没有设置成 wrap_content 或者 match_parent。

解决方法：

<androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv_list"
        android:layout_width="wrap_content"
        ... />