Android: How to get a radiogroup with togglebuttons?

I’d just re-use the RadioGroup like so: (please note the onClick attribute,i.e. a button click will trigger your Activity’s onToggle(View) method.

<RadioGroup android:id="@+id/toggleGroup"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="24dp"
            android:orientation="horizontal"
        >

    <ToggleButton android:id="@+id/btn_Letter"
                  android:layout_height="wrap_content"
                  android:layout_width="fill_parent"
                  android:layout_weight="1"
                  android:textSize="14sp"
                  android:textOn="Letter"
                  android:textOff="Letter"
                  android:onClick="onToggle"
                  android:checked="true"
            />
    <ToggleButton android:id="@+id/btn_A4"
                  android:layout_height="wrap_content"
                  android:layout_width="fill_parent"
                  android:layout_weight="1"
                  android:textSize="14sp"
                  android:textOn="A4"
                  android:textOff="A4"
                  android:onClick="onToggle"
            />
</RadioGroup>

In your Activity, or some place else, you can define a listener, e.g.

static final RadioGroup.OnCheckedChangeListener ToggleListener = new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(final RadioGroup radioGroup, final int i) {
            for (int j = 0; j < radioGroup.getChildCount(); j++) {
                final ToggleButton view = (ToggleButton) radioGroup.getChildAt(j);
                view.setChecked(view.getId() == i);
            }
        }
    };

and register it, for instance in onCreate():

@Override
 public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     this.setContentView(R.layout.scan_settings);

     ((RadioGroup) findViewById(R.id.toggleGroup)).setOnCheckedChangeListener(ToggleListener);    
 }

finally in onToggle(View), you would do whatever needs to happen, specific to your app. and also call the RadioGroup’s check method, with the toggled view’s id. Like so:

public void onToggle(View view) {
    ((RadioGroup)view.getParent()).check(view.getId());
    // app specific stuff ..
}