android RaidoGroup的使用与监听

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >

<RadioGroup
android:id="@+id/radioGroup1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal" >

<RadioButton
android:id="@+id/radio0"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:checked="true"
android:text="男" />

<RadioButton
android:id="@+id/radio1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="女" />
</RadioGroup>

</LinearLayout>

package com.example.hello;

import android.support.v7.app.ActionBarActivity;
import android.widget.RadioGroup;
import android.widget.Toast;
import android.widget.RadioGroup.OnCheckedChangeListener;
import android.os.Bundle;

public class MainActivity extends ActionBarActivity implements OnCheckedChangeListener{

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

rg = (RadioGroup) findViewById(R.id.radioGroup1);
rg.setOnCheckedChangeListener(this);

}
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
switch(checkedId){
case R.id.radio0:
Toast.makeText(MainActivity.this, "男", 1).show();
break;
case R.id.radio1:
Toast.makeText(MainActivity.this, "女", 1).show();
break;
}

}
}