ListView(下)自定义适配器

（一）

1.效果图

2.activity_main.xml

<?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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.app2.MainActivity">

    <ListView
        android:id="@+id/lv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</LinearLayout>

3.MianActivity.java

package com.example.app2;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ListView;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private ListView listView;
    private List<Student>list;
    private Student student;
    private MyAdapter myAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView = (ListView) findViewById(R.id.lv);

        //新建数据源
        list = new ArrayList<>();
        for (int i=0;i<20;i++){
            SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
            String time = simpleDateFormat.format(System.currentTimeMillis());
            student = new Student();
            student.setStuName("张三"+i);
            student.setStuNum("201503"+i);
            student.setTime(time);
            list.add(student);


        }

        //新建适配器，适配器绑定数据
        myAdapter = new MyAdapter(MainActivity.this,list);

        //视图加载适配器
        listView.setAdapter(myAdapter);





    }
}

3.Studen.java(Alt+insert快捷键提示构造方法等)

package com.example.app2;

/**
 * Created by Administrator on 2018/5/16.
 */
public class Student {
    private String stuName;
    private String stuNum;
    private String time;

    public String getStuNum() {
        return stuNum;
    }

    public void setStuNum(String stuNum) {
        this.stuNum = stuNum;
    }

    public String getStuName() {
        return stuName;
    }

    public void setStuName(String stuName) {
        this.stuName = stuName;
    }

    public String getTime() {
        return time;
    }

    public void setTime(String time) {
        this.time = time;
    }
}

4.自定义适配器MyAdapter.java

package com.example.app2;

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

import java.util.List;

/**
 * Created by Administrator on 2018/5/16.
 */
public class MyAdapter extends BaseAdapter {
    private Context context;
    private List<Student> list;

    public MyAdapter(Context context, List<Student> list) {
        this.context = context;
        this.list = list;
    }

    @Override
    public int getCount() {
        return list.size();
    }

    @Override
    public Object getItem(int position) {
        return list.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        convertView = LayoutInflater.from(context).inflate(R.layout.item,null);
        //  获取控件
        ImageView imageView = (ImageView)convertView.findViewById(R.id.iv);
        TextView tv_name = (TextView)convertView.findViewById(R.id.tv_name);
        TextView tv_num = (TextView)convertView.findViewById(R.id.tv_num);
        TextView tv_time = (TextView)convertView.findViewById(R.id.tv_time);

        Student student = list.get(position);
        imageView.setImageResource(R.mipmap.ic_launcher);
        tv_name.setText(student.getStuName());
        tv_num.setText(student.getStuNum());
        tv_time.setText(student.getTime());


        return convertView;
    }
}

5.自定义item.xml布局

<?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="match_parent"
    android:orientation="horizontal">
    <ImageView
        android:id="@+id/iv"
        android:background="@mipmap/ic_launcher"
        android:layout_width="100dp"
        android:layout_height="100dp" />
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <TextView
            android:layout_marginTop="10dp"
            android:layout_marginLeft="20dp"
            android:textSize="20dp"
            android:id="@+id/tv_name"
            android:layout_width="100dp"
            android:layout_height="50dp" />
        <TextView
            android:layout_marginLeft="20dp"
            android:textSize="20dp"
            android:id="@+id/tv_num"
            android:layout_width="100dp"
            android:layout_height="30dp" />
    </LinearLayout>
    <TextView
       android:id="@+id/tv_time"
        android:layout_marginTop="30dp"
        android:textSize="20dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</LinearLayout>

 另：优化后的MyAdapter.java

package com.example.app2;

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

import java.util.List;

/**
 * Created by Administrator on 2018/5/16.
 */
public class MyAdapter extends BaseAdapter {
    private Context context;
    private List<Student> list;

    public MyAdapter(Context context, List<Student> list) {
        this.context = context;
        this.list = list;
    }

    @Override
    public int getCount() {
        return list.size();
    }

    @Override
    public Object getItem(int position) {
        return list.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
       /* convertView = LayoutInflater.from(context).inflate(R.layout.item,null);
        //  获取控件
        ImageView imageView = (ImageView)convertView.findViewById(R.id.iv);
        TextView tv_name = (TextView)convertView.findViewById(R.id.tv_name);
        TextView tv_num = (TextView)convertView.findViewById(R.id.tv_num);
        TextView tv_time = (TextView)convertView.findViewById(R.id.tv_time);

        Student student = list.get(position);
        imageView.setImageResource(R.mipmap.ic_launcher);
        tv_name.setText(student.getStuName());
        tv_num.setText(student.getStuNum());
        tv_time.setText(student.getTime());*/
        ViewHolder viewHolder = null;
        if(viewHolder==null){
            viewHolder = new ViewHolder();
            convertView = LayoutInflater.from(context).inflate(R.layout.item,null);
            viewHolder.imageView = (ImageView)convertView.findViewById(R.id.iv);
            viewHolder.tv_name = (TextView)convertView.findViewById(R.id.tv_name);
            viewHolder.tv_num = (TextView)convertView.findViewById(R.id.tv_num);
            viewHolder.tv_time = (TextView)convertView.findViewById(R.id.tv_time);
            convertView.setTag(viewHolder);

        }else {
            viewHolder=(ViewHolder)convertView.getTag();
        }
        Student student = list.get(position);
        viewHolder.imageView.setImageResource(R.mipmap.ic_launcher);
        viewHolder.tv_name.setText(student.getStuName());
        viewHolder.tv_num.setText(student.getStuNum());
        viewHolder.tv_time.setText(student.getTime()) ;
        return convertView;
    }
    class ViewHolder{
        ImageView imageView;
        TextView tv_name ;
        TextView tv_num ;
        TextView tv_time ;
    }
}