Android_Spinner_SimpleAdapter

<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"
    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=".MainActivity" >

   <Spinner 
       android:id="@+id/spinner"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"/>

</RelativeLayout>

<?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/image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />
    <TextView 
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>

package com.example.day04_simpleadapter;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.SimpleAdapter;
import android.widget.Spinner;

public class MainActivity extends Activity {

    private Spinner spinner;
    private String[] city;
    private int[] pic;

/* SimpleAdapter：
    arraydapter  只能显示单个文本(太单一)
    SimpleAdapter 可以放置复杂样式的条目
     SimpleAdapter <List<Map<String,Object>>> adapter = new SimpleAdapter<>(
      Context context,// 上下文对象
      List<? extends Map<String, ?>> data,//   表示的是数据 ,适配控件的的每一条数据用list装,  数据用map去表示     map中的key与from参数对应
      int resource, // 一条数据（一个条目）显示的布局
      String[] from,//  与map中的多个key对应
      int[] to,//    是需要显示数据的控件的id,该id的顺序必须与from中的key对应(即key获取的值要放到id对应的控件上)
      );
      */
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        spinner = (Spinner) findViewById(R.id.spinner);
        city = new String[] {"北京","上海","杭州","深圳","广州"};
        pic = new int[] {R.drawable.ic_launcher,R.drawable.ic_launcher,R.drawable.ic_launcher,R.drawable.ic_launcher,R.drawable.ic_launcher};
        
        SimpleAdapter adapter = new SimpleAdapter(MainActivity.this, getdata(), R.layout.layout01, new String[]{"city","pic"},new int[]{R.id.text,R.id.image});
        spinner.setAdapter(adapter);
    }

    private List<? extends Map<String, ?>> getdata() {
        // TODO Auto-generated method stub
        List<Map<String,Object>> list = new  ArrayList<Map<String,Object>>();
        Map<String,Object>map = null;
        for (int i = 0; i < city.length; i++) {
            map = new HashMap<String, Object>(); 
            map.put("city",city[i]);
            map.put("pic", pic[i]);
            list.add(map);
        }
        return list;
    }


    
}