Debugger quits working in App Designer right after StartupFcn completes.

After a week of struggling with the Serial callback not working I undated to Update 8 of 2023b and that finally resolved. (I think)

MATLAB Version: 23.2.0.2599560 (R2023b) Update 8

Now (and before too but I had other problem to deal with) my program runs with AppDesigner but the debugger stops after StartupFcn completes. I can step to here:

% Construct app
function app = MouseOdor4
runningApp = getRunningApp(app);

"blah blah blah

if nargout == 0
    clear app
end
end  % last line where debugger is still running

The next step the debugger stops (my app is still running) and the editor pops up this with cursor as classdef but no marker for what line we are on.

classdef AppManagementService < handle

% APPMANAGEMENTSERVICE Singleton object to manage running apps

Any clues anyone? I'd like to get this project done!

[Alessandro Livi]

Correction:

Sometimes the debugger shows the cursor in

function runningApp = runApp(appFullFileName, appArguments)
% run app for web app (WebrAppRunner) or run app in app designer (DesktopAppRunner)
% runing app in MATLAB does not call this function
command = appdesigner.internal.service.AppManagementService.prepareCommand(appFullFileName);
if nargin == 1                       %  Yes, nargin is 1
    appArguments = '';
end
runningApp = evalin('base', sprintf('%s(%s);', command, appArguments)); % Debugger stops here?
end

[Harsh]

Hi @Alessandro Livi, is this function being called in the startup function or being used as a callback by any UI component?

[Divyam]

Hi @Alessandro Livi, share your StartupFcn and ML App. Are you using 'dbstop'/ 'uiwait' functions or referring to any other class in the code as using them might be causing your debugger to pause.

Answer 1

[Divyam]

Hi @Alessandro Livi, upon reaching the end of the callback function 'MouseOdor4' the debugger is out of the App Designer debug call stack. Since the app is no longer being debugged, your debug buttons will disappear from the App Designer.

The 'AppManagementService' code is the internal code upon which the App Designer is built on. During further execution, the debugger steps through the internal app designer code just like any debugger for an interpretted language. To skip/quit reviewing the internal files, either utilize the debugging controls in the MATLAB editor or use the Command Window commands like 'dbquit'. For more information on how to use 'dbquit', you can refer the following documentation: https://www.mathworks.com/help/matlab/ref/dbquit.html

In the 'runApp' function the debugger could stop due to two cases:

1. The "evalin" function has stepped through an infinite loop. To resolve this issue, check the expression which the function is executing.
2. The debugger has moved to evaluate the command in the "appFullFileName" file and the control for the debugger has been passed to the MATLAB editor. The debug controls of MATLAB Editor can be used to control the debugger in this case.