Android实现联动下拉框二级地市联动下拉框功能

日常使用软件中，为了方便且规范输入，会使用到下拉框进行输入，如注册时生日选项，购物时的地址输入，都会用到下拉框，今日笔者为了巩固已学的知识，实现了二级联动下拉框用作回顾及分享给求知的新手。

思路/步骤：

在实现联动下拉框之前，我们先对用到的arrayadapter和数据的封装作必要的了解，android 中提供了很多适配器的实现类，其中arrayadapter就其中之一。它可以通过泛型来指定要适配的数据类型，然后在构造函数中把要适配的数据传入。如：

arrayadapter<charsequence> adapter = arrayadapter.createfromresource(
  getapplicationcontext(), 
  r.array.province,
   android.r.layout.simple_spinner_item)；

arrayadapter中比较常用的泛型是string，但此处用了charsequence(字符序列)，通过指定泛型来装配适合的数据类型。

这段代码中有三个参数：

第一个参数context是上下文，就是当前的activity。
第二个参数是数据来源，r.array.province是存储在xml文件中的数据。
第三个参数是android sdk中内置的一个textview。(此xml文件中只有一个textview)。

通过创建一个arrayadapter处理存储在xml中的省份地市数据，用spinner控件处理arrayadapter处理好的数据，用textview将数据显示出来形成一个list供用户点击选择。

主要实现代码： mainactivity.java

import android.os.bundle;
import android.app.activity;
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;
public class mainactivity extends activity {
 spinner spinner1, spinner2;//声明两个下拉框
 string city, province;
 protected void oncreate(bundle savedinstancestate) {
 super.oncreate(savedinstancestate);
 setcontentview(r.layout.activity_main);
 spinner1 = (spinner) findviewbyid(r.id.spinner1);//绑定id
 spinner2 = (spinner) findviewbyid(r.id.spinner2);//绑定id
 arrayadapter<charsequence> adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.province,
  android.r.layout.simple_spinner_item);//创建资源
 spinner1.setadapter(adapter);//装配数据
 spinner1.setonitemselectedlistener(new provinceclicklisten());//监听事件
 spinner2.setonitemselectedlistener(new cityclicklisten());//监听事件
 }
class provinceclicklisten implements onitemselectedlistener {
 public void onitemselected(adapterview<?> parent, view v, int i, long l) {
  spinner spinner = (spinner) parent;
  string pro = (string) spinner.getitematposition(i);//获取当前选中项
  arrayadapter<charsequence> adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.def,
   r.layout.item);//初始化
  province = spinner1.getselecteditem().tostring();//当前选中的省份
  /** 根据省份，装配地市数据**/
  if (pro.equals("北京")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.北京, r.layout.item);
  } else if (pro.equals("天津")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.天津, r.layout.item);
  } else if (pro.equals("河北")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.河北, r.layout.item);
  } else if (pro.equals("山西")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.山西, r.layout.item);
  } else if (pro.equals("内蒙古")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.内蒙古, r.layout.item);
  } else if (pro.equals("辽宁")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.辽宁, r.layout.item);
  } else if (pro.equals("吉林")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.吉林, r.layout.item);
  } else if (pro.equals("黑龙江")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.黑龙江, r.layout.item);
  } else if (pro.equals("上海")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.上海, r.layout.item);
  } else if (pro.equals("江苏")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.江苏, r.layout.item);
  } else if (pro.equals("浙江")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.浙江, r.layout.item);
  } else if (pro.equals("安徽")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.安徽, r.layout.item);
  } else if (pro.equals("福建")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.福建, r.layout.item);
  } else if (pro.equals("江西")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.江西, r.layout.item);
  } else if (pro.equals("山东")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.山东, r.layout.item);
  } else if (pro.equals("河南")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.河南, r.layout.item);
  } else if (pro.equals("湖北")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.湖北, r.layout.item);
  } else if (pro.equals("湖南")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.湖南, r.layout.item);
  } else if (pro.equals("广东")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.广东, r.layout.item);
  } else if (pro.equals("广西")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.广西, r.layout.item);
  } else if (pro.equals("海南")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.海南, r.layout.item);
  } else if (pro.equals("重庆")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.重庆, r.layout.item);
  } else if (pro.equals("四川")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.四川, r.layout.item);
  } else if (pro.equals("贵州")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.贵州, r.layout.item);
  } else if (pro.equals("云南")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.云南, r.layout.item);
  } else if (pro.equals("*")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.*, r.layout.item);
  } else if (pro.equals("陕西")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.陕西, r.layout.item);
  } else if (pro.equals("甘肃")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.甘肃, r.layout.item);
  } else if (pro.equals("青海")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.青海, r.layout.item);
  } else if (pro.equals("宁夏")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.宁夏, r.layout.item);
  } else if (pro.equals("*")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.*, r.layout.item);
  } else if (pro.equals("*")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.*, r.layout.item);
  } else if (pro.equals("香港")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.香港, r.layout.item);
  } else if (pro.equals("澳门")) {
  adapter = arrayadapter.createfromresource(getapplicationcontext(), r.array.澳门, r.layout.item);
  }
  spinner2.setadapter(adapter);//装配地市数据
 }
 public void onnothingselected(adapterview<?> parent) {

 }
 }
 class cityclicklisten implements onitemselectedlistener {

 public void onitemselected(adapterview<?> parent, view v, int i, long l) {
  city = spinner2.getselecteditem().tostring();//当前选中的地市
  if (city.equals("-城市-")) {//当前还没选择地市
  } else {
  toast.maketext(getapplicationcontext(), province+"省"+city, toast.length_long).show();//toast显示选中的省份城市
  }
 }
 public void onnothingselected(adapterview<?> parent) {}
 }
 public boolean oncreateoptionsmenu(menu menu) {
 // inflate the menu; this adds items to the action bar if it is present.
 getmenuinflater().inflate(r.menu.main, menu);
 return true;
 }
}

此外还有布局文件: activity_main.xml

<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="horizontal"
  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/province"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:text="省份:" />
  <spinner
    android:id="@+id/spinner1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1" />
  <textview
    android:id="@+id/city"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:text="城市:" />
  <spinner
    android:id="@+id/spinner2"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1" />
</linearlayout>

item.xml

<?xml version="1.0" encoding="utf-8"?>
  <textview xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/spinner_item"
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:text="名称"
    android:textcolor="#000"
    android:textsize="16dp"/>

实现效果如下：

总结

以上所述是小编给大家介绍的android实现联动下拉框二级地市联动下拉框功能，希望对大家有所帮助