Accessing information within a structure in app designer and How to pass data from one push-button to the other

Hi, I am developing a simple app using the app designer. This is pretty new to me and I am not experienced when it comes to app designer or gui in general. I have the code below,

for i = numel(F(2)) 
    U_R = [F.y]';
end

1. Now F is a structure. It has 3 columns. Column 2 is labeled y and I want to assign y to U_R using U_R = [F.y]. When I run the gui I get an error '' Undefined fuction F for input arguments of type double'. How do I fix this problem?
2. Also how do I add a property section such that I can access or pass data to every pushbutton in the gui (app)?

Thank you!

[Rachel Surridge]

Hello!

1. It seems like F isn't being recognized as a structure when you use F(2) in the numel statement. Is it defined in the scope of this for loop?
2. To add a property to your app, open it in App Designer, go to Code View (a switch in the upper right hand corner of the center window). Select the Property drop-down in the top banner (in the Insert section), and select public or private property.

[Curious Mind]

1. Thanks for your response. F is a structure which is an output in workspace. How should I write the code for it to be recognized as a structure?

2. How do I add F which is a structure in the property section?

[Rachel Surridge]

2. If F is in your base MATLAB workspace, you can import it into your app using a statement like this in the properties section of the app:

properties (Access = private)
    F = evalin('base', 'F');
end

If the for loop you posted originally is inside the app, then I think the code above should resolve your first question too. F is likely not being recognized as a structure because the app doesn't know where to find it. Using the evalin statement will put F in a workspace that the app can access, so it will be able to recognize it as a structure.

[Curious Mind]

Hi Rachel, thanks for the code. F is not being displayed in the workspace. When I run the code on the matlab command line and F appears in the workspace and then I run the app using your code the it works. Is there a way I can pass information/output from the app to the workspace? As long as F appears in the workspace then your code will work because the app will recognize it. Thanks!

Answer 1

[Cris LaPierre]

In the upper left of app designer, you will have the ability to create properties. Use this to add a property to the app structure. This is what makes it available to all functions inside your app. See this page for speciic details.