Android 中 RecyclerView 的基本使用

深渊向深渊呼唤

Android 中 RecyclerView 的基本使用

1. 垂直布局 1.1 基本使用 1.2 点击事件 2. 水平布局 3. 网格布局 4. 瀑布流 5. 样式

RecyclerView 能够灵活实现大数据集的展示, 视图的复用管理比 ListView 更好, 能够显示列表、网格、瀑布流等形式, 且不同的 ViewHolder 能够实现 item 多元化的功能.

但是使用起来会稍微麻烦一点, 并且没有类似 ListView 的 onItemClickListene r监听事件, 需要开发者自己实现.

新版本不用导入下面依赖的

implementation 'com.android.support:cardview-v7:26.1.0'
implementation 'com.android.support:recyclerview-v7:26.1.0'

1. 垂直布局

在这里插入图片描述

1.1 基本使用

LinearRecyclerViewActivity

package com.example.hello.recyclerView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.view.View;

import com.example.hello.R;

public class LinearRecyclerViewActivity extends AppCompatActivity {

    // 声明
    private RecyclerView rv1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_linear_recycler_view);
        // 获取
        rv1 = findViewById(R.id.rv_1);
        rv1.setLayoutManager(new LinearLayoutManager(LinearRecyclerViewActivity.this));
        // 添加分割线
        rv1.addItemDecoration(new Decoration());
        rv1.setAdapter(new LinearViewAdapterActivity(LinearRecyclerViewActivity.this));
    }

    /**
     * 设置分割线
     */
    class Decoration extends RecyclerView.ItemDecoration {

        @Override
        public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
            super.getItemOffsets(outRect, view, parent, state);
            outRect.set(0, 0, 0, getResources().getDimensionPixelOffset(R.dimen.dividerHeight));
        }

    }
}

outRect.set(0, 0, 0, getResources().getDimensionPixelOffset(R.dimen.dividerHeight));
这句中的 dividerHeight 来自文件 dimens.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <dimen name="dividerHeight">2dp</dimen>
</resources>

activity_linear_recycler_view

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:andro
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_
    android:layout_
    tools:context=".recyclerView.LinearRecyclerViewActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:
        android:layout_
        android:layout_ />

</RelativeLayout>

LinearViewAdapterActivity

package com.example.hello.recyclerView;

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 com.example.hello.R;

public class LinearViewAdapterActivity extends RecyclerView.Adapter<LinearViewAdapterActivity.LinearViewHolder> {

    private Context context;

    public LinearViewAdapterActivity(Context context) {
        this.context = context;
    }

    @NonNull
    @Override
    public LinearViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return new LinearViewHolder(LayoutInflater.from(context).inflate(R.layout.layout_linear_item, parent, false));
    }

    @Override
    public void onBindViewHolder(@NonNull LinearViewHolder holder, int position) {
        CharSequence charSequence = "Hello World!";
        holder.ltv.setText(charSequence);
    }

    @Override
    public int getItemCount() {
        return 30;
    }

    /**
     * 封装控件
     */
    static class LinearViewHolder extends RecyclerView.ViewHolder {
        private TextView ltv;

        public LinearViewHolder(@NonNull View itemView) {
            super(itemView);
            ltv = itemView.findViewById(R.id.linear_tv);
        }
    }

}

layout_linear_item

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:andro
    android:layout_
    android:layout_
    android:background="@color/yellow_blew"
    android:clickable="true"
    android:orientation="vertical"
    android:padding="15dp">

    <TextView
        android:
        android:layout_
        android:layout_
        android:background="@drawable/bg_btn2"
        android:gravity="center"
        android:padding="5dp"
        android:text="@string/app_name"
        android:textColor="@color/black"
        android:textSize="20sp" />

</LinearLayout>

在这里插入图片描述

1.2 点击事件

在这里插入图片描述

在这个文件内设置不方便, 想在 LinearRecyclerViewActivity 文件内设置.

LinearViewAdapterActivity 文件改变如下

package com.example.hello.recyclerView;

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 com.example.hello.R;

public class LinearViewAdapterActivity extends RecyclerView.Adapter<LinearViewAdapterActivity.LinearViewHolder> {

    private Context context;
    private OnItemClickListener listener;

    public LinearViewAdapterActivity(Context context, OnItemClickListener listener) {
        this.context = context;
        this.listener = listener;
    }

    @NonNull
    @Override
    public LinearViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return new LinearViewHolder(LayoutInflater.from(context).inflate(R.layout.layout_linear_item, parent, false));
    }

    @Override
    public void onBindViewHolder(@NonNull LinearViewHolder holder, int position) {
        CharSequence charSequence = "Hello World!";
        holder.ltv.setText(charSequence);
        // 点击事件
        holder.ltv.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                listener.onClick(position);
            }
        });
    }

    @Override
    public int getItemCount() {
        return 30;
    }

    /**
     * 封装控件
     */
    static class LinearViewHolder extends RecyclerView.ViewHolder {
        private TextView ltv;

        public LinearViewHolder(@NonNull View itemView) {
            super(itemView);
            ltv = itemView.findViewById(R.id.linear_tv);
        }
    }

    /**
     * 设置监听接口
     */
    public interface OnItemClickListener {
        void onClick(int position);
    }

}

LinearRecyclerViewActivity 文件改变如下

package com.example.hello.recyclerView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

import com.example.hello.R;

public class LinearRecyclerViewActivity extends AppCompatActivity {

    // 声明
    private RecyclerView rv1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_linear_recycler_view);
        // 获取
        rv1 = findViewById(R.id.rv_1);
        rv1.setLayoutManager(new LinearLayoutManager(LinearRecyclerViewActivity.this));
        // 添加分割线
        rv1.addItemDecoration(new Decoration());
        rv1.setAdapter(new LinearViewAdapterActivity(LinearRecyclerViewActivity.this, new LinearViewAdapterActivity.OnItemClickListener() {
            @Override
            public void onClick(int position) {
                Toast.makeText(LinearRecyclerViewActivity.this, position + " 进行了点击", Toast.LENGTH_SHORT).show();
            }
        }));
    }

    /**
     * 设置分割线
     */
    class Decoration extends RecyclerView.ItemDecoration {

        @Override
        public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
            super.getItemOffsets(outRect, view, parent, state);
            outRect.set(0, 0, 0, getResources().getDimensionPixelOffset(R.dimen.dividerHeight));
        }

    }
}

在这里插入图片描述

2. 水平布局

和垂直的没有什么区别

    设置成水平布局 分割线改成右侧 item 和其他文件相应改动
package com.example.hello.recyclerView;

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

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

import com.example.hello.R;

public class HorRecyclerViewActivity extends AppCompatActivity {

    // 声明
    private RecyclerView rv2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_hor_recycler_view);
        // 获取
        rv2 = findViewById(R.id.rv_2);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(HorRecyclerViewActivity.this);
        // 设置水平方向
        linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
        rv2.setLayoutManager(linearLayoutManager);
        // 添加分割线
        rv2.addItemDecoration(new Decoration());
        rv2.setAdapter(new HorViewAdapterActivity(HorRecyclerViewActivity.this, new HorViewAdapterActivity.OnItemClickListener() {
            @Override
            public void onClick(int position) {
                Toast.makeText(HorRecyclerViewActivity.this, position + " 进行了点击", Toast.LENGTH_SHORT).show();
            }
        }));
    }

    /**
     * 设置分割线
     */
    class Decoration extends RecyclerView.ItemDecoration {

        @Override
        public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
            super.getItemOffsets(outRect, view, parent, state);
            outRect.set(0, 0, getResources().getDimensionPixelOffset(R.dimen.dividerHeight), 0);
        }

    }
}

在这里插入图片描述

3. 网格布局

和垂直, 水平的也没有什么区别

    设置成网格布局 分割线改成全部 item 和其他文件相应改动
package com.example.hello.recyclerView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

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

import com.example.hello.R;

public class GridRecyclerViewActivity extends AppCompatActivity {

    // 声明
    private RecyclerView rv3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_grid_recycler_view);
        // 获取
        rv3 = findViewById(R.id.rv_3);
        // 每行显示三个
        rv3.setLayoutManager(new GridLayoutManager(GridRecyclerViewActivity.this, 3));
        // 添加分割线
        rv3.addItemDecoration(new Decoration());
        rv3.setAdapter(new GridViewAdapterActivity(GridRecyclerViewActivity.this, new GridViewAdapterActivity.OnItemClickListener() {
            @Override
            public void onClick(int position) {
                Toast.makeText(GridRecyclerViewActivity.this, position + " 进行了点击", Toast.LENGTH_SHORT).show();
            }
        }));
    }


    /**
     * 设置分割线
     */
    class Decoration extends RecyclerView.ItemDecoration {

        @Override
        public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
            super.getItemOffsets(outRect, view, parent, state);
            int height = getResources().getDimensionPixelOffset(R.dimen.dividerHeight);
            //noinspection SuspiciousNameCombination
            outRect.set(height, height, height, height);
        }

    }
}

4. 瀑布流

在这里插入图片描述

和上面的操作也没有什么区别, 为了看出不同, item 中改成了长度不同的照片.

    设置成瀑布流形式 item 改成照片 item 和其他文件相应改动

PuRecyclerViewActivity

package com.example.hello.recyclerView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.RecyclerView;
import androidx.recyclerview.widget.StaggeredGridLayoutManager;

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

import com.example.hello.R;

public class PuRecyclerViewActivity extends AppCompatActivity {

    // 声明
    private RecyclerView rv4;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_pu_recycler_view);
        // 得到内容
        rv4 = findViewById(R.id.rv_4);
        // StaggeredGridLayoutManager.VERTICAL 代表有多少列, StaggeredGridLayoutManager.HORIZONTAL  代表有多少行
        rv4.setLayoutManager(new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL));
        // 添加分割线
        rv4.addItemDecoration(new Decoration());
        rv4.setAdapter(new StaggeredGridViewAdapterActivity(PuRecyclerViewActivity.this, new StaggeredGridViewAdapterActivity.OnItemClickListener() {
            @Override
            public void onClick(int position) {
                Toast.makeText(PuRecyclerViewActivity.this, position + " 进行了点击", Toast.LENGTH_SHORT).show();
            }
        }));
    }



    /**
     * 设置分割线
     */
    class Decoration extends RecyclerView.ItemDecoration {

        @Override
        public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
            super.getItemOffsets(outRect, view, parent, state);
            int height = getResources().getDimensionPixelOffset(R.dimen.dividerHeight);
            //noinspection SuspiciousNameCombination
            outRect.set(height, height, height, height);
        }

    }
}

StaggeredGridViewAdapterActivity

package com.example.hello.recyclerView;

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

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

import com.example.hello.R;

public class StaggeredGridViewAdapterActivity extends RecyclerView.Adapter<StaggeredGridViewAdapterActivity.LinearViewHolder> {

    private Context context;
    private OnItemClickListener listener;

    public StaggeredGridViewAdapterActivity(Context context, OnItemClickListener listener) {
        this.context = context;
        this.listener = listener;
    }

    @NonNull
    @Override
    public LinearViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return new LinearViewHolder(LayoutInflater.from(context).inflate(R.layout.layout_staggered_grid_item, parent, false));
    }

    @Override
    public void onBindViewHolder(@NonNull LinearViewHolder holder, int position) {
        // 两列显示不同的内容
        int imageResource = position % 2 != 0 ? R.mipmap.beautiful : R.mipmap.long_up;
        holder.iv.setImageResource(imageResource);
        // 点击事件
        holder.iv.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                listener.onClick(position);
            }
        });
    }

    @Override
    public int getItemCount() {
        return 30;
    }

    /**
     * 封装控件
     */
    static class LinearViewHolder extends RecyclerView.ViewHolder {
        private ImageView iv;

        public LinearViewHolder(@NonNull View itemView) {
            super(itemView);
            iv = itemView.findViewById(R.id.staggered_grid_iv);
        }
    }

    /**
     * 设置监听接口
     */
    public interface OnItemClickListener {
        void onClick(int position);
    }

}

layout_staggered_grid_item

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:andro
    android:layout_
    android:layout_
    android:background="@color/yellow_blew"
    android:clickable="true"
    android:orientation="horizontal"
    android:padding="15dp">

    <ImageView
        android:
        android:layout_
        android:layout_
        android:contentDescription="@string/beautiful"
        android:scaleType="centerCrop"
        android:src="@mipmap/beautiful" />

</LinearLayout>

在这里插入图片描述

5. 样式

不同的 ViewHolder.
XRecyclerView: addHeadView, addFootView, 下拉刷新, 上拉加载.

水平布局布局为例子. 将其改成一个是汉字一个是照片.

新建 layout_linear_item2.xml 文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:andro
    android:layout_
    android:layout_
    android:background="@color/yellow_blew"
    android:clickable="true"
    android:orientation="vertical"
    android:padding="15dp">

    <TextView
        android:
        android:layout_
        android:layout_
        android:background="@drawable/bg_btn3"
        android:gravity="center"
        android:padding="5dp"
        android:text="@string/app_name"
        android:textColor="@color/black"
        android:textSize="20sp" />

    <ImageView
        android:
        android:layout_
        android:layout_
        android:layout_marginTop="10dp"
        android:contentDescription="@string/app_name"
        android:scaleType="fitCenter"
        android:src="@mipmap/ic_launcher_round" />

</LinearLayout>

在这里插入图片描述

LinearViewAdapterActivity

package com.example.hello.recyclerView;

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

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

import com.example.hello.R;

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

    private Context context;
    private OnItemClickListener listener;

    public LinearViewAdapterActivity(Context context, OnItemClickListener listener) {
        this.context = context;
        this.listener = listener;
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        if (viewType == 0) {
            return new LinearViewHolder(LayoutInflater.from(context).inflate(R.layout.layout_linear_item, parent, false));
        } else {
            return new LinearViewHolder2(LayoutInflater.from(context).inflate(R.layout.layout_linear_item2, parent, false));
        }
    }

    @Override
    public int getItemViewType(int position) {
        return position % 2 == 0 ? 0 : 1;
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        if (getItemViewType(position) == 0) {
            CharSequence charSequence = "Hello World!";
            ((LinearViewHolder) holder).ltv.setText(charSequence);
            // 点击事件
            ((LinearViewHolder) holder).ltv.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    listener.onClick(position);
                }
            });
        } else {
            CharSequence charSequence = "Nice to meet you!";
            ((LinearViewHolder2) holder).ltv.setText(charSequence);
            // 点击事件
            ((LinearViewHolder2) holder).ltv.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    listener.onClick(position);
                }
            });
            ((LinearViewHolder2) holder).liv.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    listener.onClick(position);
                }
            });
        }
    }

    @Override
    public int getItemCount() {
        return 30;
    }

    /**
     * 封装控件
     */
    static class LinearViewHolder extends RecyclerView.ViewHolder {
        private TextView ltv;

        public LinearViewHolder(@NonNull View itemView) {
            super(itemView);
            ltv = itemView.findViewById(R.id.linear_tv);
        }
    }

    /**
     * 封装控件
     */
    static class LinearViewHolder2 extends RecyclerView.ViewHolder {
        private TextView ltv;
        private ImageView liv;

        public LinearViewHolder2(@NonNull View itemView) {
            super(itemView);
            ltv = itemView.findViewById(R.id.linear_tv);
            liv = itemView.findViewById(R.id.linear_iv);
        }
    }

    /**
     * 设置监听接口
     */
    public interface OnItemClickListener {
        void onClick(int position);
    }

}

在这里插入图片描述

栏目