Timer Interrupt in App Designer

Hi,

I am trying to implement a timer interrupt in app designer,

I did the following

• define t in properties
• init timer in startupFcn

app.t=timer;
            app.t.TimerFcn = @DisplayFPS;
            app.t.Period =1;
            app.t.ExecutionMode = 'fixedRate';

• implement timer callback function inside private methods

 function DisplayFPS(app,mTimer,~)
            framerate= app.framescount/app.framestime;
            message = sprintf("Frame rate = %f f/s",framerate);
            app.ResultTextArea.Value = [message;app.ResultTextArea.Value];
            app.framescount = 0;
            app.framestime = 0;
  end

but I get the following error when I start

Error while evaluating TimerFcn for timer 'timer-2' 
Undefined function 'DisplayFPS' for input arguments of type 'timer'.

How could I overcome this problem?

Answer 1

[Guillaume]

app.t.TimerFcn = @app.DisplayFPS;  %<--DisplayFPS is a method of the app, so must be called with app argument

[Hossam Alzomor]

Thanks for reply

after doing modification I get another error

Error while evaluating TimerFcn for timer 'timer-1' 
Matrix dimensions must agree.

[Guillaume]

So, it's calling your callback now, but there's a bug in your callback.

Possibly app.framescount or app.framestime is not scalar.

We'd need to see the full error message to be sure. In any case, that's nothing to do with your original question.