Android实现下拉菜单Spinner效果

<?xml version="1.0" encoding="utf-8"?> 
<linearlayout 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:orientation="vertical" 
  tools:context="com.rj141.sb.kongjian.mainactivity"> 
 
  <linearlayout 
    android:orientation="horizontal" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content"> 
    <textview 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:textsize="18dp" 
      android:text="请选择您最喜欢的水果：" /> 
 
    <spinner 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:id="@+id/spinner" /> 
  </linearlayout> 
 
 
  <textview 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textsize="18dp" 
    android:id="@+id/tv" /> 
 
</linearlayout> 

public class mainactivity extends appcompatactivity { 
 
  private spinner s; 
  string[] data=new string[]{"苹果","雪梨","西瓜","葡萄","橙子","草莓"}; 
  private textview tv; 
 
  @override 
  protected void oncreate(bundle savedinstancestate) { 
    super.oncreate(savedinstancestate); 
    setcontentview(r.layout.activity_main); 
 
    tv= (textview) this.findviewbyid(r.id.tv); 
    s= (spinner) this.findviewbyid(r.id.spinner); 
    s.setadapter(new arrayadapter<string>(this,android.r.layout.simple_list_item_1,data)); 
    s.setonitemselectedlistener(new adapterview.onitemselectedlistener() { 
      @override 
      public void onitemselected(adapterview<?> parent, view view, int position, long id) { 
        string str=data[position]; 
        tv.settext("最喜欢的水果是："+str); 
      } 
      @override 
      public void onnothingselected(adapterview<?> parent) { 
      } 
    }); 
  } 
} 
s.setadapter(new arrayadapter<string>(this,android.r.layout.simple_list_item_1,data))；android.r.layout.simple_list_item_1是指安卓自带的下拉列表格式，data是数据源；
s.setonitemselectedlistener(new adapterview.onitemselectedlistener()){..}；是下拉列表的监听