Android使用Spinner控件实现下拉列表的案例

<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"  
  <TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:layout_marginTop="46dp"
    android:text="所属城市"
    android:textSize="22sp" / 
  <Spinner
    android:id="@+id/spinner1"
    android:layout_width="200sp"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_marginTop="44dp"
    android:layout_toRightOf="@+id/textView1" / 
  <TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignRight="@+id/textView1"
    android:layout_centerVertical="true"
    android:text="所属星球" / 
  <Spinner
    android:id="@+id/spinner2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/spinner1"
    android:layout_alignTop="@+id/textView2"
    android:layout_marginLeft="21dp" / 
</RelativeLayout 

package com.example.spinners;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;
/**
 * 通过继承OnItemSelectedListener接口来实现选择时的事件
 * @author xuliugen
 *
 */
public class MainActivity extends Activity implements OnItemSelectedListener {
 private Spinner spinner1;
 private Spinner spinner2;
 // private SpinnerAdapter spinnerAdapter;
 private ArrayAdapter<String  adapter;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 spinner1 = (Spinner) this.findViewById(R.id.spinner1);
 spinner2 = (Spinner) this.findViewById(R.id.spinner2);
 // 第一种手工输入的list
 adapter = new ArrayAdapter<String (MainActivity.this,
  android.R.layout.simple_spinner_item, getDataSource());
 spinner1.setAdapter(adapter);
 //注册监听器
 spinner1.setOnItemSelectedListener(this);
 // 第二种：通过加载xml文件配置的数据源
 ArrayAdapter adapter2 = ArrayAdapter.createFromResource(this,
  R.array.planets_array, android.R.layout.simple_spinner_item);
 adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
 spinner2.setAdapter(adapter2);
 }
 /*
 * 通过第一种方法：手工输入的list
 */
 public List<String  getDataSource() {
 List<String  list = new ArrayList<String ();
 list.add("beijing");
 list.add("beida");
 list.add("shahai");
 list.add("shangjing");
 list.add("shanglian");
 list.add("chengdu");
 return list;
 }
 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
 getMenuInflater().inflate(R.menu.main, menu);
 return true;
 }
 @Override
 public void onItemSelected(AdapterView<?  parent, View view, int position,
  long id) {
 String itemString = spinner1.getItemAtPosition(position).toString();
 Toast.makeText(this, "你选中的是" + itemString, 1).show();
 }
 @Override
 public void onNothingSelected(AdapterView<?  parent) {
 }
}

<?xml version="1.0" encoding="utf-8"? 
<resources 
  <string name="app_name" Spinners</string 
  <string name="action_settings" Settings</string 
  <string name="hello_world" Hello world!</string 
  <string-array name="planets_array" 
    <item Mercury</item 
    <item Venus</item 
    <item Earth</item 
    <item Mars</item 
    <item Jupiter</item 
    <item Saturn</item 
    <item Uranus</item 
    <item Neptune</item 
  </string-array 
</resources