android实现下拉菜单三级联动

<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="com.example.spinner.mainactivity" >
 
  <spinner android:layout_width="match_parent"
    android:layout_height="wrap_content"
    
    android:id="@+id/spn"
    android:dropdownwidth="200dp"/>
  
  <spinner android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_below="@id/spn"
    android:id="@+id/city"
    android:dropdownwidth="200dp"/>
  <spinner android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_below="@id/city"
    android:id="@+id/counstryside"
    android:dropdownwidth="200dp"/>
 
</relativelayout>

package com.example.spinner;
 
import android.app.activity;
import android.os.bundle;
import android.view.view;
import android.widget.adapterview;
import android.widget.adapterview.onitemselectedlistener;
import android.widget.arrayadapter;
import android.widget.spinner;
 
/**
 * @author zmc
 * 三级联动主要是灵活的应用三维数组
 */
public class mainactivity extends activity {
 private string province[] = new string[]{"江西","湖南"};
 private spinner spinner1,spinner2,spinner3;
 private int provinceindex;
 private string city [][] = {{"南昌","赣州"},{"长沙","湘潭"}};
 private string counstryside [][][] = {{{"青山湖区","南昌县"},{"章贡区","赣县"}},{{"长沙县","沙县"},{"湘潭县","象限"}}};
 arrayadapter<string> adapter1,adapter2,adapter3;
 @override
 protected void oncreate(bundle savedinstancestate) {
 super.oncreate(savedinstancestate);
 setcontentview(r.layout.activity_main);
 spinner1 = (spinner) findviewbyid(r.id.spn);
 adapter1 = new arrayadapter<>(this, android.r.layout.simple_dropdown_item_1line,province);
 spinner1.setadapter(adapter1);
 
 spinner2 = (spinner)findviewbyid(r.id.city);
 adapter2 = new arrayadapter<>(this, android.r.layout.simple_dropdown_item_1line,city[0]);
 spinner2.setadapter(adapter2);
 
 spinner3 = (spinner)findviewbyid(r.id.counstryside);
 adapter3 = new arrayadapter<>(this, android.r.layout.simple_dropdown_item_1line,counstryside[0][0]);
 spinner3.setadapter(adapter3);
 spinner1.setonitemselectedlistener(new onitemselectedlistener() {
 
  @override
  public void onitemselected(adapterview<?> parent, view view,
   int position, long id) {
  // todo auto-generated method stub
  provinceindex = position;
  adapter2 = new arrayadapter<>(mainactivity.this, android.r.layout.simple_dropdown_item_1line,city[position]);
  spinner2.setadapter(adapter2);
  }
 
  @override
  public void onnothingselected(adapterview<?> parent) {
  // todo auto-generated method stub
  
  }
 });
 
 spinner2.setonitemselectedlistener(new onitemselectedlistener() {
 
  @override
  public void onitemselected(adapterview<?> parent, view view,
   int position, long id) {
  // todo auto-generated method stub
  
  adapter3 = new arrayadapter<>(mainactivity.this, android.r.layout.simple_dropdown_item_1line,counstryside[provinceindex][position]);
  //adapter3.notifydatasetchanged();
  spinner3.setadapter(adapter3);
  }
 
  @override
  public void onnothingselected(adapterview<?> parent) {
  // todo auto-generated method stub
  //当时据为空的时候触发的
  }
 });
 
 
 }
 
 
}