App Designer: Radio buttons that prompt User input (Novice)

In my data, each object is scored compared to a reference (range 0-1). In the GUI, the user will be given three options: use no threshold, only select objects meeting a score threshold, and select top X% of scores. If they choose a threshold or top X% I want the user to specify a value 0-1 for the threshold or percentage. If I use radio buttons for these three options, how can I prompt/allow user input?

Answer 1

[Adam Danz]

In the "selection changed" callback function to the radio buttons group, you can ask the user for more information using the inputdlg(). This example below asks for more information if the button named "button2" was selected.

 % Selection changed function: ButtonGroup
        function ButtonGroupSelectionChanged(app, event)
        
        
            selectedButton = app.ButtonGroup.SelectedObject;
            if strcmpi(selectedButton.Text,'Button2') % If button2 was selected...
                answer = inputdlg('Specify value between 0:1','More info needed');
                answer = str2double(answer{:});
            end
            
            
            
        end

***See comments below for better strategies that do not rely on hard coded strings.

[Guillaume]

While that would indeed do what was asked, in term of UI design it's horrendous.

• Mistakenly click on the radio button, get a modal dialog window that you have to dismiss. This is particularly bad for keyboard users who would be cycling through the different options and would get the dialog each time they went over the option.
• Realise you've entered the wrong value in the dialog, you have to first select another option, before selecting the option again to get the dialog

A much better design would be to have a numeric edit field on the row of the radio button. That edit field would be enabled/disabled in the SelectionChanged event depending on the radio button selection:

 % Selection changed function: ButtonGroup
        function ButtonGroupSelectionChanged(app, event)
            selectedButton = app.ButtonGroup.SelectedObject;
            %assuming that the edit field associated with Button2 is called EditFieldButton2:
            app.EditFieldButton2.Enabled = strcmp(selectedButton.Text, 'Button2');
        end

While the edit field is enabled the user can easily change the value, and once you execute your actual processing code, if selection is option2, you simply fetch the threshold from the edit field control.

[Adam Danz]

Yeah, I agree that a numeric edit field is the better idea. This should be an additional answer (and a better one).

[Guillaume]

Well, the idea is to use the SelectionChange callback to do whatever needs doing, I'm just suggesting a better action for that callback.

[Steven Lord]

Rather than checking the text of the selected button to determine if it is the one that should enable the edit box, I would directly check the object. This way your code doesn't need to change if you decide you want to adjust the wording or if you need to translate the labels to a different language. The latter is probably not all that common a workflow, but the former is.

The SelectionChangedFcn receives some information that will help you do this. Something like this should work, though I haven't tested it. ThresholdPercentage is the edit box in which the user can enter their threshold / percentage and UserSpecifiedPercentage is the radio button that should enable that box.

app.ThresholdPercentage.Enabled = ...
    event.NewValue == app.UserSpecifiedPercentage;

For a little more self-explanatory (but slightly more verbose) code, store event.NewValue in a variable, something like buttonUserSelected.

buttonUserSelected = event.NewValue;
app.ThresholdPercentage.Enabled = ...
    buttonUserSelected == app.UserSpecifiedPercentage;

[Adam Danz]

Good point. I'll have to tinker around with that.

Here's another alternative that does not rely on hard coded string names.

% Determine if button 2 was pressed. 
if find(ismember(get(app.ButtonGroup.Buttons,'Text'),event.NewValue.Text)) == 2

I really wish there were a buttongroup property that just returns the integer index of the selected button (in the order that the buttons were created). It seems obvious to have that.