RadioButton 选中问题

final RadioGroup radioGroup=(RadioGroup) findViewById(R.id.radioGroup1);
		final RadioButton rb0=(RadioButton) findViewById(R.id.radio0);
		final RadioButton rb1=(RadioButton) findViewById(R.id.radio1);

		radioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener() {
			@Override
			public void onCheckedChanged(RadioGroup group, int checkedId) {
				// TODO Auto-generated method stub
				switch (checkedId) {
				case R.id.radio0:
					radioGroup.check(rb0.getId()); 
					break;
				case R.id.radio1:
					radioGroup.check(rb1.getId()); 
					break;
				default:
					break;
				}

				System.out.println();
			}
		});

		Button btn =(Button) findViewById(R.id.btn);
		btn.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				radioGroup.clearCheck();
			}
		});

 布局文件activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <RadioGroup
        android:id="@+id/radioGroup1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:checkedButton="@+id/radio0" >

        <RadioButton
            android:id="@+id/radio0"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="RB0" />

        <RadioButton
            android:id="@+id/radio1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="RB1" />
    </RadioGroup>

    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="点击" />

</LinearLayout>