Android控件Spinner实现下拉列表及监听功能

<Spinner 
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:id="@+id/spinner2"
  android:entries="@array/spingarr"
  />

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <string-array name="spingarr">
   <item>北京</item> 
  <item>上海</item> 
  <item>广州</item> 
  <item>深圳</item> 
  </string-array>
</resources>

package com.example.testspanner;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
public class MainActivity extends Activity {
private Spinner spinner;
private List<String> data_list;
private ArrayAdapter<String> arr_adapter;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.spinner);
    spinner = (Spinner) findViewById(R.id.spinner);
    //数据
    data_list = new ArrayList<String>();
    data_list.add("北京");
    data_list.add("上海");
    data_list.add("广州");
    data_list.add("深圳");
    //适配器
    arr_adapter= new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, data_list);
    //设置样式
    arr_adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    //加载适配器
    spinner.setAdapter(arr_adapter);
  }
}

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

 mySpinner.setOnItemSelectedListener(new Spinner.OnItemSelectedListener() {//选择item的选择点击监听事件 
          public void onItemSelected(AdapterView<?> arg0, View arg1, 
              int arg2, long arg3) { 
            // TODO Auto-generated method stub 
            // 将所选mySpinner 的值带入myTextView 中  
            myTextView.setText("您选择的是：" + arg2+"个");//文本说明 
          } 
          public void onNothingSelected(AdapterView<?> arg0) { 
            // TODO Auto-generated method stub 
            myTextView.setText("Nothing"); 
          } 
        });