自定义RecyclerView适配器实现列表

快来打我* 2023-06-12 08:49 6阅读 0赞

适配器作用：绑定布局文件的数据（数据是什么？怎么展示？）  
没有导入RecyclerView依赖的请参考：[https://blog.csdn.net/weixin\_42230348/article/details/103020497][https_blog.csdn.net_weixin_42230348_article_details_103020497]

## 适配器实现准备： ##

1、一个**RecyclerView**活动+布局（布局一般是以列表的形式将数据展示出了）  
2、定义一个实体类Entity:为接下来设置和传递实体数据做准备  
3、**ListDemoAdapter:** 自定义适配器  
4、**item\_list\_demo布局：** 设定数据每一行怎么展示？

## 具体实现如下： ##

1、一个**RecyclerView**活动+布局（布局一般是以列表的形式将数据展示出了）

import androidx.appcompat.app.AppCompatActivity;
    import androidx.recyclerview.widget.LinearLayoutManager;
    import androidx.recyclerview.widget.RecyclerView;
    
    import android.os.Bundle;
    
    import java.util.ArrayList;
    import java.util.List;
    
    public class RecyclerViewActivity extends AppCompatActivity { 
    	
    	private RecyclerView recyclerView ;
    	
    	private ListDemoAadapter adapter ;
    	
    	private List<Entity> data ;
    	  
        @Override
        protected void onCreate(Bundle savedInstanceState) { 
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_recycler_view);
            recyclerView = findViewById(R.id.cycler_view) ;
            //设置布局管理器
            recylerView.setLayoutManager(new LinearLayoutManager(this)) ;
            //设置适配器
            adapter =  new ListDemoAdapter(null) ; //获得自定义适配器实例
            recyclerView.setAdapter(adapter); 
            initData();
        }
        //为实体赋值并将加载到适配器中
        private void initData(){ 
        	data = new ArrayList<>() ;
        	for(int i=0; i<100 ; i++){ 
        		Entity entity = new Entity("index" + i) ;
        		data.add(entity) ;
        	}
        	adapter.setData(data) ;
        }
    }

activity\_recycler\_view布局

2、定义一个实体类Entity:为接下来设置和传递实体数据做准备

import android.os.Parcel;
    import android.os.Parcelable;
    
    //序列化，目的是为了数据的传输
    public class Entity implements Parcelable
    { 
    
        private int count;
    
        private String msg;
    
        public Entity(int count)
        { 
            this.count = count;
        }
    
        public Entity(int count, String msg)
        { 
            this.count = count;
            this.msg = msg;
        }
    
        public Entity(String msg)
        { 
            this.msg = msg;
        }
    
        public int getCount()
        { 
            return count;
        }
    
        public void setCount(int count)
        { 
            this.count = count;
        }
    
        public String getMsg()
        { 
            return msg;
        }
    
        public void setMsg(String msg)
        { 
            this.msg = msg;
        }
    
        @Override
        public int describeContents() {  return 0; }
    
        @Override
        public void writeToParcel(Parcel dest, int flags)
        { 
            dest.writeInt(this.count);
            dest.writeString(this.msg);
        }
    
        protected Entity(Parcel in)
        { 
            this.count = in.readInt();
            this.msg = in.readString();
        }
    
        public static final Parcelable.Creator<Entity> CREATOR = new Parcelable.Creator<Entity>()
        { 
            @Override
            public Entity createFromParcel(Parcel source) { return new Entity(source);}
    
            @Override
            public Entity[] newArray(int size) { return new Entity[size];}
        };
    }

3、**ListDemoAdapter:** 自定义适配器

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;
    
    //自定义适配器
    public class ListDemoAdapter extends RecyclerView.Adapter<ListDemoAdapter.ListViewHolder> { 
        private List<Entity> data;
    
        public ListDemoAdapter(List<Entity> data)
        { 
            this.data = data;
        }
    
        public void setData(List<Entity> data)
        { 
            this.data = data;
            // 刷新数据
            notifyDataSetChanged();
        }
    
        /** *创建一个viewHolder并返回 * @param parent 相当于Item存放的容器 * @param viewType 指定布局文件的类型 * @return 返回viewHolder对象 */
        @NonNull
        @Override
        public ListViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { 
            //指定对应的布局文件
           View view =  LayoutInflater.from(parent.getContext()).inflate(R.layout.item_list_demo,parent,false);
            return new ListViewHolder(view);
    
        }
    
        /** * 将数据加载到布局文件的控件上 * @param holder 需要绑定数据的viewHolder * @param position 列表数据的下标 */
        @Override
        public void onBindViewHolder(@NonNull ListDemoAdapter.ListViewHolder holder, int position) { 
            Entity entity = data.get(position);
            holder.textView.setText(entity.getMsg());
        }
    
        /** *返回数据的大小 * @return */
        @Override
        public int getItemCount() { 
            return data == null ? 0 : data.size();
        }
        //为了系统复用控件
        static class ListViewHolder extends RecyclerView.ViewHolder
        { 
            TextView textView;
    
            public ListViewHolder(@NonNull View itemView)
            { 
                super(itemView);
                // 实例化该控件
                textView = itemView.findViewById(R.id.tv_text);
            }
        }
    }

4、**item\_list\_demo布局：** 设定数据每一行怎么展示？

<?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="wrap_content"
        android:orientation="vertical">
    
        <TextView
            android:id="@+id/tv_text"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:gravity="center_horizontal"
            android:padding="30dp"
            android:textSize="18sp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.0"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            tools:text="TextView"
            tools:textColor="@color/colorPrimary"
            tools:textSize="30sp" />
    
        <View
            android:id="@+id/textView7"
            android:layout_width="0dp"
            android:layout_height="2dp"
            android:layout_marginBottom="4dp"
            android:background="#4E0B0B"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/tv_text" />
    
    
    </androidx.constraintlayout.widget.ConstraintLayout>

ok,大功告成！！！  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjIzMDM0OA_size_16_color_FFFFFF_t_70]

[https_blog.csdn.net_weixin_42230348_article_details_103020497]: https://blog.csdn.net/weixin_42230348/article/details/103020497
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjIzMDM0OA_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20191112141350126.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjIzMDM0OA==,size_16,color_FFFFFF,t_70