How to get the selected index of a RadioGroup in Android

You should be able to do something like this:

int radioButtonID = radioButtonGroup.getCheckedRadioButtonId();
View radioButton = radioButtonGroup.findViewById(radioButtonID);
int idx = radioButtonGroup.indexOfChild(radioButton);

If the RadioGroup contains other Views (like a TextView) then the indexOfChild() method will return wrong index.

To get the selected RadioButton text on the RadioGroup:

 RadioButton r = (RadioButton) radioButtonGroup.getChildAt(idx);
 String selectedtext = r.getText().toString();

You could have a reference to the radio group and use getCheckedRadioButtonId () to get the checked radio button id. Take a look here

RadioGroup radioGroup = (RadioGroup)findViewById(R.id.radio_group);

Then when you need to get the selected radio option.

int checkedRadioButtonId = radioGroup.getCheckedRadioButtonId();
if (checkedRadioButtonId == -1) {
    // No item selected
}
else{
    if (checkedRadioButtonId == R.id.radio_button1) {
        // Do something with the button
    }
}

This should work,

int index = myRadioGroup.indexOfChild(findViewById(myRadioGroup.getCheckedRadioButtonId()));