Question

I tried to implement a radiogroup with four togglebuttons. The desired behaviour is the typical radio group behaviour: One button is preselected, if the user clicks another button, the previous one is unselected and the new one selected instead. If the user clicks a selected button again nothing should happen since its not allowed to have none of the buttons selected. And thats where I got problems. I followed the solution to this question: Android: How to get a radiogroup with togglebuttons?

Unfortunately the user is still able to deselect the active button. How can I prevent this?

Heres my code:

The onClick Listener for the ToggleButtons:

/**
 * Handler for onClick Events.
 */
    @Override
public void onClick(View v) {
    if (viewListener == null) {
        return;
    }
    if (v == tb_one|| v == tb_two|| v == tb_three|| v == tb_four) {
        ((RadioGroup) v.getParent()).check(v.getId());
    }
    else {
        super.onClick(v);
    }

}

My custom OnCheckedChangeListener:

/**
 * The listener for a checked change event of the toggle buttons.
 */
static final RadioGroup.OnCheckedChangeListener ToggleListener = new RadioGroup.OnCheckedChangeListener() {
    @Override
    public void onCheckedChanged(final RadioGroup radioGroup, final int i) {
        //if one button is checked, uncheck all others
        for (int j = 0; j < radioGroup.getChildCount(); j++) {
            final ToggleButton view = (ToggleButton) radioGroup.getChildAt(j);
            view.setChecked(view.getId() == i);
        }
    }
};

And heres where I add the listeners: (its in the onFinishInflate method)

    ((RadioGroup) findViewById(R.id.instant_toggleGroup_mode))
            .setOnCheckedChangeListener(ToggleListener);
    tb_one = (ToggleButton) findViewById(R.id.instant_tb_one);
    tb_one.setOnClickListener(this);
    tb_two = (ToggleButton) findViewById(R.id.instant_tb_two);
    tb_two.setOnClickListener(this);
    tb_three = (ToggleButton) findViewById(R.id.instant_tb_three);
    tb_three.setOnClickListener(this);
    tb_four = (ToggleButton) findViewById(R.id.instant_tb_four);
    tb_four.setOnClickListener(this);

Would be great if someone could point out the solution to me!

Answer 1

Finally I figured out how to do it. Thanks Ole, your help led me to this solution.

So this is the working code:

Initializing the buttons and the button group:

tb_one = (ToggleButton) findViewById(R.id.instant_tb_one);
tb_one.setOnClickListener(this);
tb_two = (ToggleButton) findViewById(R.id.instant_tb_two);
tb_two.setOnClickListener(this);
tb_three = (ToggleButton) findViewById(R.id.instant_tb_three);
tb_three.setOnClickListener(this);
tb_four = (ToggleButton) findViewById(R.id.instant_tb_four);
tb_four.setOnClickListener(this);
rg_modes = (RadioGroup) findViewById(R.id.instant_toggleGroup_mode);
rg_modes.setOnCheckedChangeListener(ToggleListener);
rg_modes.clearCheck();
rg_modes.check(tb_one.getId());

The onClick Handler:

if (v == tb_one|| v == tb_two|| v == tb_three|| v == tb_four) {
  rg_modes.clearCheck();
  rg_modes.check(v.getId());
}