Radio Button

XML

<RadioGroup    

   android:id="@+id/radio1"    

   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>

JAVA

RadioGroup st;
RadioButton radPa,radPi;

rg = (RadioGroup) findViewById(R.id.radio1);
radPa= (RadioButton) findViewById(R.id.radPa);
radPi= (RadioButton) findViewById(R.id.radPi);

String JK=myJSON.getString(TAG_jenis_kelamin);
if(JK.equalsIgnoreCase("Perempuan")){
   ((RadioButton)rg.getChildAt(1)).setChecked(true);
}
else{//Laki-laki   ((RadioButton)st.getChildAt(0)).setChecked(true);
}
String ljenis_kelamin="Laki-Laki";
if(radPi.isChecked()){ljenis_kelamin="Perempuan";}