第20章、OnCheckedChangeListener事件（从零开始学Android）

单选按钮RadioGroup、复选框CheckBox都有OnCheckedChangeListener事件，我们一起了解一下。

一、布局

　　1、打开“res/layout/activity_main.xml”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"
     tools:context=".MainActivity" >

     <RadioGroup
         android:id="@+id/gender"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentLeft="true"
         android:layout_alignParentTop="true" >
         <RadioButton
             android:id="@+id/male"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:checked="true"
             android:text="男" />
         <RadioButton
             android:id="@+id/female"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:text="女" />
     RadioGroup>

     <CheckBox
         android:id="@+id/football"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentLeft="true"
         android:layout_below="@+id/gender"
         android:text="足球" />
     <CheckBox
         android:id="@+id/basketball"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentLeft="true"
         android:layout_below="@+id/football"
         android:text="蓝球" />

 RelativeLayout>

　　2、界面如下：

　　

 

二、OnCheckedChangeListener事件　

　　打开“src/com.genwoxue.oncheckedchanged/MainActivity.java”文件。

　　然后输入以下代码：　　

 package com.genwoxue.oncheckedchanged;

 import android.os.Bundle;
 import android.app.Activity;
 import android.widget.RadioGroup;
 import android.widget.RadioButton;
 import android.widget.RadioGroup.OnCheckedChangeListener;              //引入OnCheckedChangeListener事件相关包
 import android.widget.CheckBox;
 import android.widget.CompoundButton;
 import android.widget.Toast;


 public class MainActivity extends Activity {
     private RadioGroup GenderGroup=null;
     private RadioButton rbMale=null;
     private RadioButton rbFemale=null;
     private CheckBox cbFootBall=null;
     private CheckBox cbBasketBall=null;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         GenderGroup=(RadioGroup)super.findViewById(R.id.gender);
         rbMale=(RadioButton)super.findViewById(R.id.male);
         rbFemale=(RadioButton)super.findViewById(R.id.female);
         cbFootBall=(CheckBox)super.findViewById(R.id.football);
         cbBasketBall=(CheckBox)super.findViewById(R.id.basketball);
         //在GenderGroup注册OnCheckedChangeListener事件
                   GenderGroup.setOnCheckedChangeListener(new GenderOnCheckedChangeListener());
                   //在cbFootBall注册OnCheckedChangeListener事件
         cbFootBall.setOnCheckedChangeListener(new BootBallOnCheckedChangeListener());
                   //在cbBasketBall注册OnCheckedChangeListener事件

         cbBasketBall.setOnCheckedChangeListener(new BasketBallOnCheckedChangeListener());
     }

     private class GenderOnCheckedChangeListener implements OnCheckedChangeListener{
         @Override
         public void onCheckedChanged(RadioGroup group,int checkedId){
             String sGender="";
             if(rbFemale.getId()==checkedId){
                 sGender=rbFemale.getText().toString();
             }
             if(rbMale.getId()==checkedId){
                 sGender=rbMale.getText().toString();
             }
             Toast.makeText(getApplicationContext(), "您选择的性别是："+sGender, Toast.LENGTH_LONG).show();
         }

     }

     private class BootBallOnCheckedChangeListener implements CompoundButton.OnCheckedChangeListener{
         @Override
         public void onCheckedChanged(CompoundButton button, boolean isChecked){
             String sFav="";
             if(isChecked){
                 sFav=cbFootBall.getText().toString();
                 sFav=sFav+"选中！";
             }
             else
                 sFav=sFav+"未迁中";
             Toast.makeText(getApplicationContext(), "您选择的爱好是："+sFav, Toast.LENGTH_LONG).show();
         }
     }

     private class BasketBallOnCheckedChangeListener implements CompoundButton.OnCheckedChangeListener{
         @Override
         public void onCheckedChanged(CompoundButton button,boolean isChecked){
             String sFav="";
             if(cbBasketBall.isChecked()){
                 sFav=cbBasketBall.getText().toString();
                 sFav=sFav+"选中！";
             }
             else
                 sFav=sFav+"未迁中";
             Toast.makeText(getApplicationContext(), "您选择的爱好是："+sFav, Toast.LENGTH_LONG).show();
         }
     }

 }

　　尽管单选按钮和复选框都有OnCheckedChange事件，但注意二者区别。

　　效果如下：