android实现下拉菜单 * 联动

android中的下拉菜单联动应用非常普遍，android中的下拉菜单用Spinner就能实现，以下列子通过简单的代码实现 * 菜单联动。

一 样式文件

<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>

二 联动逻辑代码

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
* * 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
 }
});

}

}

三 结果

四 总结

* 联动主要是灵活的应用三维数组，这样能很方便的通过数组索引将三个菜单关联，同时通过设置Spinner的setOnItemSelectedListener来监听选择的动作，动态设置下拉菜单的内容。

来源：https://blog.csdn.net/AirMario/article/details/53583993