Android编程之下拉菜单Spinner控件用法示例

<?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="vertical"  
  <TextView
    android:id="@+id/textView"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textSize="25sp"
    android:textColor="#ff0000"
    / 
  <Spinner
    android:id="@+id/spinner"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" / 
</LinearLayout 

package com.example.hello;
import java.util.ArrayList;
import java.util.List;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;
public class MainActivity extends ActionBarActivity implements OnItemSelectedListener{
  private TextView textView;
  private Spinner spinner;
  private List<String  list;
  private ArrayAdapter<String  adapter;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    textView = (TextView) findViewById(R.id.textView);
    textView.setText("您选择的城市是：");
    spinner = (Spinner) findViewById(R.id.spinner);
    list = new ArrayList<String ();
    list.add("北京");
    list.add("上海");
    list.add("广州");
    list.add("深圳");
    adapter = new ArrayAdapter<String (this, android.R.layout.simple_spinner_item,list);
    adapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
    spinner.setAdapter(adapter);
    spinner.setOnItemSelectedListener(this);
  }
  @Override
  public void onItemSelected(AdapterView<?  arg0, View arg1, int arg2,long arg3) {
    String cityName = adapter.getItem(arg2);
    //String city = list.get(arg2);
    textView.setText("您选择的城市是："+cityName);
  }
  @Override
  public void onNothingSelected(AdapterView<?  arg0) {
    // TODO Auto-generated method stub
  }
}