Android : ListView + BaseAdapter-简单应用

 ​​容器与适配器：​​​​​        http://t.csdnimg.cn/ZfAJ7

示例图：

实体类 News.java

package com.example.mylistviewbaseadapter.entity;
 
 
public class News {
    private   String title;
    private  String content;
    private int img;
 
    public News(String title,String content, int img){
        this.title = title;
        this.content = content;
        this.img =img;
    }
 
    public String getTitile() {
        return title;
    }
 
    public void setTitile(String title) {
        this.title = title;
    }
 
    public String getContent() {
        return content;
    }
 
    public void setContent(String content) {
        this.content = content;
    }
 
    public int getImg() {
        return img;
    }
 
    public void setImg(int img) {
        this.img = img;
    }
}

适配器 写个类继承BaseAdapter 

package com.example.mylistviewbaseadapter;
 
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
 
import com.example.mylistviewbaseadapter.entity.News;
 
import java.util.List;
 
public class NewsAdpater extends BaseAdapter {
    private List date;
    private Context context;
    //構造器
    public NewsAdpater(List date,Context context){
        this.date = date;
        this.context = context;
    }
 
    //BaseAdapter最基本的几个方法：
    // 1. getCount 填充的数据集数
    // 2.getItem 数据集中指定索引对应的数据项
    // 3. getItemId 指定行所对应的ID
    // 4. getView 每个Item所显示的类容
 
    @Override
    public int getCount() {
        //充的数据集数
        return date.size();
    }
 
    @Override
    public Object getItem(int position) {
        //数据集中指定索引对应的数据项
        return date.get(position);
    }
 
    @Override
    public long getItemId(int position) {
        // 指定行所对应的ID
        return position;
    }
 
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        //每个Item所显示的类容
 
        convertView =  LayoutInflater.from(context).inflate(R.layout.list_test,parent,false);
        ImageView imageView = convertView.findViewById(R.id.btnImg);
        TextView tvTitle = convertView.findViewById(R.id.tvH);
        TextView tbCont = convertView.findViewById(R.id.tvCont);
 
        //摄入值
        imageView.setBackgroundResource(date.get(position).getImg());
        tvTitle.setText(date.get(position).getTitile());
        tbCont.setText(date.get(position).getContent());
        return convertView;
    }
/**
     //优化
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHoler holer = null;
        if(holer == null){
            holer = new ViewHoler();
            //每个Item所显示的类容
            convertView =  LayoutInflater.from(context).inflate(R.layout.list_test,parent,false);
            holer.imageView = convertView.findViewById(R.id.btnImg);
            holer.tvTitle = convertView.findViewById(R.id.tvH);
            holer.tbCont = convertView.findViewById(R.id.tvCont);
            convertView.setTag(holer);
        }else{
            holer = (ViewHoler)convertView.getTag();
        }
        //摄入值
        holer.imageView.setBackgroundResource(date.get(position).getImg());
        holer.tvTitle.setText(date.get(position).getTitile());
        holer.tbCont.setText(date.get(position).getContent());
        return convertView;
    }
    static class ViewHoler{
        ImageView imageView;
        TextView tvTitle;
        TextView tbCont;
    }
*/
}

MainActivity.java

package com.example.mylistviewbaseadapter;
 
import static android.widget.Toast.LENGTH_SHORT;
 
import androidx.appcompat.app.AppCompatActivity;
 
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;
 
 
import com.example.mylistviewbaseadapter.entity.News;
 
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
 
public class MainActivity extends AppCompatActivity{
 
   
    private ListView listView;
    private Context context;
    private List listNews =null;
 
    //适配器
    private  NewsAdpater newsAdpater=null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        context = this;
 
        listView = findViewById(R.id.listVi);
 
        listNews = new ArrayList<>();
        //传入内容
        for(int i= 0 ; i < 10; i++){
            listNews.add(new News("这是标题"+i,"我是内容我是内容我是内容我是内容我是内容我是内容我是内容"+i,R.mipmap.bg));
        }
        newsAdpater = new NewsAdpater(listNews,context);
 
          //事件
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView parent, View view, int position, long id) {
                Toast.makeText(context, "点击了第" + position + "条数据", LENGTH_SHORT).show();
            }
        });
        //往容器设置适配器
        listView.setAdapter(newsAdpater);
    }
 
  
 
}

activity_main.xml

"1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context=".MainActivity">
 
    <ListView
        android:id="@+id/listVi"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
 
LinearLayout>

list_test.xml

"1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:descendantFocusability="blocksDescendants"
    android:layout_height="match_parent">
    
    <ImageView
        android:id="@+id/btnImg"
        android:layout_width="200dp"
        android:layout_height="100dp"
        android:scaleType="fitXY"
        android:src="@mipmap/bg"
        />
    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <TextView
            android:id="@+id/tvH"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="我是标题"
            android:gravity="center"
            android:textSize="16sp"
            android:textStyle="bold"
            />
        <ScrollView
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
 
        <TextView
            android:id="@+id/tvCont"
            android:layout_marginTop="10px"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="我是内容文本asdfasdfasdfasdfasdfasdfs"
            android:textSize="12sp"
            android:textStyle=""
            />
        ScrollView>
    LinearLayout>
LinearLayout>