andorid 列表视图 ListView 之BaseAdapter

.xml

<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/lv_2">

</ListView>

.java   //  BaseAdapter

package com.hanqi.application3;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

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

public class UIActivity5 extends AppCompatActivity {

    //List<Map<String,Object>> lm;
    List<Food> lf;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_ui5);

        ListView lv_2 = (ListView)findViewById(R.id.lv_2);

        lf= new ArrayList<Food>();

        lf.add(new Food(R.drawable.an1, "内容1","美食1"));
        lf.add(new Food(R.drawable.an2, "内容2", "美食2"));
        lf.add(new Food(R.drawable.an3, "内容3", "美食3"));
        lf.add(new Food(R.drawable.an1, "内容4","美食4"));
        lf.add(new Food(R.drawable.an1, "内容5","美食5"));
        lf.add(new Food(R.drawable.an2, "内容6","美食6"));
        lf.add(new Food(R.drawable.an3, "内容7","美食7"));
        lf.add(new Food(R.drawable.an1, "内容8","美食8"));
        lf.add(new Food(R.drawable.an1, "内容9","美食9"));
        lf.add(new Food(R.drawable.an2, "内容10","美食10"));
        lf.add(new Food(R.drawable.an3, "内容11","美食11"));
        lf.add(new Food(R.drawable.an1, "内容12","美食12"));

        //准备数据源
//        lm = new ArrayList<Map<String,Object>>();
//
//        Map<String, Object> map=new HashMap<String, Object>();
//        map.put("image",R.drawable.an1);
//        map.put("name","美食图片01");
//        map.put("content","看上去很好吃01");
//        lm.add(map);
//
//        map=new HashMap<String, Object>();
//        map.put("image",R.drawable.an2);
//        map.put("name","美食图片02");
//        map.put("content","看上去很好吃02");
//        lm.add(map);
//
//        map=new HashMap<String, Object>();
//        map.put("image",R.drawable.an3);
//        map.put("name","美食图片03");
//        map.put("content","看上去很好吃03");
//        lm.add(map);
        lv_2.setAdapter(new MyBaseAdapter());

    }

    class MyBaseAdapter extends BaseAdapter
    {
        //获取要显示的列表的行数
        @Override
        public int getCount() {
            return lf.size();
        }
        //获取对应下标行
        @Override
        public Object getItem(int position) {
            return lf.get(position);
        }
        //获取对应下标行的id
        @Override
        public long getItemId(int position) {
            return position;
        }
        //给视图适配数据  返回视图
        //position  数据的下标
        // convertView  可重复使用
        //parent  父视图
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            //如果 convertView为null  就加载layout文件
            if(convertView == null) {

                //1.获取样式layout文件
                LayoutInflater layoutInflater = getLayoutInflater();
                convertView  = layoutInflater.inflate(R.layout.layout_simple, null);
            }
            //2.数据和layout文件的视图组件进行绑定
            //1)从数据源里获取一行数据
            //Map<String, Object> map = lf.get(position);
            Food food = lf.get(position);
            //2)获取layout文件的视图组件
            ImageView iv_2 = (ImageView)convertView.findViewById(R.id.iv_2);
            TextView  tv_1=(TextView)convertView.findViewById(R.id.tv_1);
            TextView  tv_2=(TextView)convertView.findViewById(R.id.tv_2);
            //3)数据适配
//            iv_2.setImageResource((int)map.get("image"));
//            tv_1.setText(map.get("name").toString());
//            tv_2.setText(map.get("content").toString());
            iv_2.setImageResource(food.getImage());
            tv_1.setText(food.getName());
            tv_2.setText(food.getContent());
            //3.返回视图
            return convertView;

        }
    }
}

layout_simple.xml

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

    <ImageView
        android:layout_width="70dp"
        android:layout_height="70dp"
        android:src="@drawable/an1"
        android:id="@+id/iv_2"/>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_gravity="center_vertical"
        android:layout_marginLeft="20dp">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="美食图片"
            android:id="@+id/tv_1"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="很好吃的样子"
            android:id="@+id/tv_2"/>

    </LinearLayout>

</LinearLayout>