How to get the value of Radio buttons from App Designer

Here is my radio button:

app.ButtonGroup

• app.A_button
• app.B_button

What I want to do is this:

Button A should be the default button. If the button A is stay pushed or the user does not do anything to this group of buttons, my button value should be 10. If Button B is pushed, my overall button value should be 14.

How can I achieve that? Sorry for the basic question. I'm new to app designer.

[Geoff Hayes]

Leon - what do you mean by button value? Is this a value that you use in some sort of calculation?

[Leon]

Yes, it is a value I use for some later calculation.

We can derive these values fomr an if loop, I guess.

If Button A is slected 
Val = 10
else 
Val = 14
end

My problem is that I do not know how to specify the if sentence.

Thanks

Answer 1

[Adam Danz]

The 'Value' property of the radio buttons returns a logical that is true when selected and false otherwise. Here's an example to follow below.

if app.Button1.Value   %where "Button1" is the name of the first radio button
    Val = 10
elseif app.Button2.Value
    Val = 14
else
    Val = 0; 
end

Another way to do that is to use the 'SelectedObject' property of the ButtonGroup along with a switch-case.

switch app.ButtonGroup.SelectedObject.Text
    case 'Button1' %where "Button1" is the name of the first radio button
        val = 10; 
    case 'Button2'
        val = 14; 
    otherwise
        val = 0; 
end

[Leon]

Thank you so much, Adam!

Liqing

[Adam Danz]

Glad I could help!

[Nirzar Doshi]

This was very helpful! Thank you Adam!

[Veena Chatti]

Thanks! I also found this very helpful

[Csanád Temesvári]

For me it throws an "Unable to resolve the name app.Button1.Value" error. Could you please helpme with that?

[Adam Danz]

You can't just copy and paste code and expect it to work. The error message indicates that the variable names I used aren't the variable names you used.

[Csanád Temesvári]

I know that, but I didn't want to necessary confuse you with hungarian variable names :)

[Adam Danz]

@Csanád Temesvári when I lived in Bulgaria I was friends with some people at the Hungarian Embassy and can imagine what Hungarian variable names look like 😄. But I'm used to uninterpretable var names so that's ok.

What version of Matlab are you using, what's the full error message, and can you share the line of code that produces the error?

[Csanád Temesvári]

Absolutely!

First some preliminaries: I'm making a school assignment showcasing various affine transformations using homogenous coordinates.

The premise is the following: The user enters numerical values for the transformations (translation vector, angle of rotation, etc., ) into text edit fields, I convert the characters into vectors, create the appropriate matrix, multiply the converted point coordinates with the transformation matrix, convert it back to normal coordinates and then plot the results according to what "shape" the user wants to transform (top left).

That's where the error comes in.

Here's the mesage and the code it produces:

Unable to resolve the name app.Alakzat_2D_ButtonGroup.SelectedObject.Text.

Error in transzform/points_2D_boxValueChanged (line 374)
            plot_2D(app)
            
            
function [] = plot_2D(~)
            switch app.Alakzat_2D_ButtonGroup.SelectedObject.Text
                case "Pont"
                    scatter(app.UIAxes_2D, app.PlottedData_2D(:, 1), app.PlottedData_2D(:, 2), 'filled')
                case "Bézier-görbe"
                    sym t
                    D = bernsteinMatrix(size(app.PlottedData_2D, 1) - 1, t);
                    beziergorbe = simplify(D*app.PlottedData_2D);
                    fplot(app.UIAxes_2D, beziergorbe(:, 1), beziergorbe(:, 2), [0 1])
                    hold on
                    scatter(app.UIAxes_2D, app.PlottedData_2D(:, 1), app.PlottedData_2D(:, 2), 'filled')
                    hold off
                case "Sokszög"
                    fill(app.UIAxes_2D, app.PlottedData_2D(:, 1), app.PlottedData_2D(:, 2), 'b')
            end
end

I tried both the SelectedObject.Text and the if Button.Value methods and none of them worked.

I hope this isn't egregious and makes sense :)

[Adam Danz]

> Unable to resolve the name app.Alakzat_2D_ButtonGroup.SelectedObject.Text.

Take a look at your function,

function [] = plot_2D(~)
    switch app.Alakzat_2D_ButtonGroup.SelectedObject.Text

It has no inputs.

You have to pass the app variable to it and there should be a warning in AppDesigner on that line of code indicating that you're not passing the app variable, unless this function is outside of AppDesigner.

[Csanád Temesvári]

Thank you so much!

Obviously, I ran into further problems after I fixed that one, but that's just programming :)