代码如下：

public class MainActivity extends Activity {

 public RadioGroup mRadioGroup1;
 public RadioButton mRadio1, mRadio2;

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

  mRadioGroup1 = (RadioGroup) findViewById(R.id.gendergroup);
  mRadio1 = (RadioButton) findViewById(R.id.girl);
  mRadio2 = (RadioButton) findViewById(R.id.boy);
  mRadioGroup1.setOnCheckedChangeListener(radiogpchange);

 }

 private RadioGroup.OnCheckedChangeListener radiogpchange = new RadioGroup.OnCheckedChangeListener() {
  @Override
  public void onCheckedChanged(RadioGroup group, int checkedId) {
   if (checkedId == mRadio1.getId()) {
    Toast.makeText(getApplicationContext(), "女孩", 1).show();
   } else if (checkedId == mRadio2.getId()) {
    Toast.makeText(getApplicationContext(), "男孩", 1).show();
   }
  }
 };
}

RadioButton:就像是C#中的Radio控件，可以为控件设置Group，每个Group中的项只能选择一项；
代码如下：

    <RadioGroup

        android:id="@+id/gendergroup"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:orientation="vertical" >

        <RadioButton

            android:id="@+id/girl"

            android:layout_width="fill_parent"

            android:layout_height="wrap_content"

            android:text="@string/girl" />

        <RadioButton

            android:id="@+id/boy"

            android:layout_width="fill_parent"

            android:layout_height="wrap_content"

            android:text="@string/boy" />

    </RadioGroup>