列表和适配器（ListView和Adapter）

列表

布局文件里写：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
tools:context="com.example.ygd.jreduch04.ListViewActivity">

<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/list1"
android:entries="@array/listData"
>

</ListView>

</RelativeLayout>

value-strings里面添加

<string-array name="listData">
<item>张三</item>
<item>李四</item>
<item>王五</item>
<item>赵六</item>
<item>田七</item>
</string-array>

2.适配器

连接后端数据和前端显示的接口

决定数据在UI上如何显示

ArrayAdapter：最为简单，只能展示一行文字
//ListView本身有与ArrayAdapter对应的接口
ListView lv=(ListView)findViewById(R.id.list1);
//定义ListView要显示的数据
String[] names={"张三","李四","王五","赵六","田七","胡巴","久久"};
/*初始化适配器
参数1：Context上下文信息
参数2：布局文件
参数3：要填充的数据
*/
ArrayAdapter aa=new ArrayAdapter(this,android.R.layout.simple_list_item_1,names);
//ListView设置适配器
lv.setAdapter(aa);
Spinner用法与其一致：
//定义ListView要显示的数据
String[] names={"张三","李四","王五","赵六","田七","胡巴","久久"};
/*初始化适配器
参数1：Context上下文信息
参数2：布局文件
参数3：要填充的数据
*/
ArrayAdapter aa=new ArrayAdapter(this,android.R.layout.simple_spinner_item,names);

Spinner sp=(Spinner)findViewById(R.id.sp1);
sp.setAdapter(aa);
SimpleAdapter有较好的扩充性，可以自定义布局
（from指的是来自map的哪一组数据，to指的是放到哪一个控件里去）
List list=new ArrayList();
Map map=new HashMap();
map.put("name", "张三");
list.add(map);
map=new HashMap();
map.put("name", "李四");
list.add(map);
map=new HashMap();
map.put("name", "王五");
list.add(map);
map=new HashMap();
map.put("name", "赵六");
list.add(map);
SimpleAdapter sa=new SimpleAdapter(this,list,android.R.layout.simple_list_item_1,new String[]{"name"},new int[]{android.R.id.text1});

ListView lv=(ListView)findViewById(R.id.list1);
lv.setAdapter(sa);
simple_list_item_2的用法：
List list=new ArrayList();
Map map=new HashMap();
map.put("name", "张三");
map.put("age",20);
list.add(map);
map=new HashMap();
map.put("name", "李四");
map.put("age",21);
list.add(map);
map=new HashMap();
map.put("name", "王五");
map.put("age",22);
list.add(map);
map=new HashMap();
map.put("name", "赵六");
map.put("age",23);
list.add(map);
SimpleAdapter sa=new SimpleAdapter(this,list,android.R.layout.simple_list_item_2,new String[]{"name","age"},new int[]{android.R.id.text1,android.R.id.text2});

ListView lv=(ListView)findViewById(R.id.list1);
lv.setAdapter(sa);
//设置监听
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Map m=(Map)list.get(position);
Toast.makeText(getBaseContext(),"您点击了"+(m.get("name")),Toast.LENGTH_SHORT).show();
}
});

BaseAdapter：抽象类，具有较高的灵活性

（先新建一个News实体类）

package com.example.ygd.jreduch04.entity;

/**
* Created by ygd on 2016/4/5.
*/
public class News {
private int newsId;
private String title;
private String content;
private String pubDate;
private String newsFrom;
private int[] img;
private String comCount;

public News(){}
public News(int newsId, String title, String content, String pubDate, String newsFrom, int[] img, String comCount) {
this.newsId = newsId;
this.title = title;
this.content = content;
this.pubDate = pubDate;
this.newsFrom = newsFrom;
this.img = img;
this.comCount = comCount;
}

public int getNewsId() {
return newsId;
}

public void setNewsId(int newsId) {
this.newsId = newsId;
}

public String getTitle() {
return title;
}

public void setTitle(String title) {
this.title = title;
}

public String getContent() {
return content;
}

public void setContent(String content) {
this.content = content;
}

public String getPubDate() {
return pubDate;
}

public void setPubDate(String pubDate) {
this.pubDate = pubDate;
}

public String getNewsFrom() {
return newsFrom;
}

public void setNewsFrom(String newsFrom) {
this.newsFrom = newsFrom;
}

public int[] getImg() {
return img;
}

public void setImg(int[] img) {
this.img = img;
}

public String getComCount() {
return comCount;
}

public void setComCount(String comCount) {
this.comCount = comCount;
}
}

新建一个package名为adapter，在下面新建一个java文件MyAdapter

package com.example.ygd.jreduch04.adapter;

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.ygd.jreduch04.R;
import com.example.ygd.jreduch04.entity.News;

import java.util.List;

public class MyAdapter extends BaseAdapter{
private List<News> myData;
private Context context;

public MyAdapter(Context context,List myData) {
this.context = context;
this.myData = myData;
}

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

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

@Override
public long getItemId(int position) {
return myData.get(position).getNewsId();
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v=LayoutInflater.from(context).inflate(R.layout.list_layout_1,null);
ImageView imageView=(ImageView)v.findViewById(R.id.imag1);
TextView textView=(TextView)v.findViewById(R.id.text1);
News news=myData.get(position);
textView.setText(news.getTitle());
imageView.setImageResource(news.getImg()[0]);
return v;
}
}

新建一个Activity命名为BaseAdapterActivity

package com.example.ygd.jreduch04;

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

import com.example.ygd.jreduch04.adapter.MyAdapter;
import com.example.ygd.jreduch04.entity.News;

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

public class BaseAdapterActivity extends AppCompatActivity {
private List myData;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_base_adapter);
loadData();
ListView listView=(ListView)findViewById(R.id.list1);
MyAdapter ma=new MyAdapter(this,myData);
listView.setAdapter(ma);
}
public void loadData(){
myData=new ArrayList();
News news=new News(1,"亚冠1","首尔FCvs山东鲁能","2016-04-05","新浪体育",new int[]{R.mipmap.ic_launcher},"800");
myData.add(news);
news=new News(2,"亚冠2","首尔FCvs山东鲁能","2016-04-05","新浪体育",new int[]{R.mipmap.aa},"800");
myData.add(news);
news=new News(3,"亚冠3","首尔FCvs山东鲁能","2016-04-05","新浪体育",new int[]{R.mipmap.bb},"800");
myData.add(news);
news=new News(4,"亚冠4","首尔FCvs山东鲁能","2016-04-05","新浪体育",new int[]{R.mipmap.dice01},"800");
myData.add(news);
news=new News(5,"亚冠5","首尔FCvs山东鲁能","2016-04-05","新浪体育",new int[]{R.mipmap.dice02},"800");
myData.add(news);
news=new News(6,"亚冠6","首尔FCvs山东鲁能","2016-04-05","新浪体育",new int[]{R.mipmap.dice03},"800");
myData.add(news);
news=new News(7,"亚冠7","首尔FCvs山东鲁能","2016-04-05","新浪体育",new int[]{R.mipmap.dice04},"800");
myData.add(news);
news=new News(8,"亚冠8","首尔FCvs山东鲁能","2016-04-05","新浪体育",new int[]{R.mipmap.dice05},"800");
myData.add(news);
news=new News(9,"亚冠9","首尔FCvs山东鲁能","2016-04-05","新浪体育",new int[]{R.mipmap.dice06},"800");
myData.add(news);
news=new News(10,"亚冠10","首尔FCvs山东鲁能","2016-04-05","新浪体育",new int[]{R.mipmap.ic_launcher},"800");
myData.add(news);
}

}

设置监听可直接在MyAdapter里面写匿名监听