RadioButton Group Checked

RadioGroup rg;

rg = (RadioGroup) findViewById(R.id.radiogroup);

if(JK.equalsIgnoreCase("Perempuan")){
   ((RadioButton)rg.getChildAt(1)).setChecked(true);
}
else{//Laki-laki
   ((RadioButton)rg.getChildAt(0)).setChecked(true);
}

===========================

<TextView    android:layout_width="fill_parent"    android:layout_height="wrap_content"    android:text="Jenis Kelamin"    android:textColor="#000000"    android:textSize="20sp"    android:textStyle="bold"/>

<RadioGroup    android:id="@+id/radio"    android:layout_width="fill_parent"    android:layout_height="wrap_content"    android:orientation="vertical">
    <RadioButton android:id="@+id/radPa"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Laki-laki"        android:checked="true" />
    <RadioButton android:id="@+id/radPi"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Perempuan" />
</RadioGroup>