android RadioGroup的使用方法

<?xml version="1.0" encoding="UTF-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="fill_parent" 
android:layout_height="fill_parent" 
android:orientation="vertical"> 
<TextView 
android:id="@+id/radiobutton_textview" 
android:layout_width="fill_parent" 
android:layout_height="50dip" 
android:textSize="18dip" 
android:textStyle="bold" 
android:background="@android:drawable/title_bar" 
android:textAppearance="?android:attr/textAppearanceLarge" 
android:gravity="center_vertical" 
/> 
<RadioGroup 
android:id="@+id/group" 
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
android:orientation="vertical"> 
<RadioButton 
android:id="@+id/button1" 
android:layout_width="fill_parent" 
android:layout_height="50dip" 
android:textSize="20dip" 
android:paddingLeft="30dip" 
android:text="Android新手" 
android:button="@null" 
android:drawableRight="@android:drawable/btn_radio"/> 
<View 
android:layout_width="fill_parent" 
android:layout_height="1px" 
android:background="?android:attr/listDivider" 
/> 
<RadioButton 
android:id="@+id/button2" 
android:layout_width="fill_parent" 
android:layout_height="50dip" 
android:textSize="20dip" 
android:paddingLeft="30dip" 
android:text="Android高手" 
android:button="@null" 
android:drawableRight="@android:drawable/btn_radio"/> 
</RadioGroup> 
</LinearLayout> 

package endual.radio; 
import android.app.Activity; 
import android.os.Bundle; 
import android.widget.RadioButton; 
import android.widget.RadioGroup; 
import android.widget.RadioGroup.OnCheckedChangeListener; 
import android.widget.TextView; 
public class MainActivity extends Activity { 
private TextView textView; 
private RadioGroup group; 
private RadioButton rb1 ; 
private RadioButton rb2 ; 
/** Called when the activity is first created. */ 
@Override 
public void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
setContentView(R.layout.main); 
textView = (TextView) findViewById(R.id.radiobutton_textview); 
group = (RadioGroup) findViewById(R.id.group); 
this.rb1 = (RadioButton) this.findViewById(R.id.button1) ; 
this.rb2 = (RadioButton) this.findViewById(R.id.button2) ; 

// 单选按钮组监听事件 
group.setOnCheckedChangeListener(new OnCheckedChangeListener() { 
@Override 
public void onCheckedChanged(RadioGroup group, int checkedId) { 
// 根据ID判断选择的按钮 
if (checkedId == R.id.button1) { 

textView.setText("Android新手"); 
rb1.setText("我是1") ; 
String msg = rb1.getText().toString() ; //获取单独的radioButton的按钮 
rb2.setText(msg) ; 
//System.out.println(); 
} else { 
textView.setText("Android高手"); 
rb2.setText("我是2") ; 
} 
} 
}); 
} 
}