RadioButton

<RadioButton
  android:id="@+id/rbAdd"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:text="Add"
/>




    
            


final RadioGroup rbgroup = (RadioGroup)findViewById(R.id.rbgroup);
bn1.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        switch (rbgroup.getCheckedRadioButtonId()) {
            case R.id.rbAdd:
                edittext1.setText("add is selected");
                break;
            case R.id.rbSub:
                edittext1.setText("sub is selected");
                break;
            default:
                edittext1.setText("weder add noch sub is selected");
                break;
        }
    }
});