Callback of uicontrol fails to execute

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abc 2013-11-9

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评论： abc 2013-11-10

Hi,

I have an application for which I developed a progressbar figure with the help of a function I wrote progressbar_auto. I wanted a cancel button on the progressbar which I created using uicontrol. The callback function is executed ONLY when I put a breakpoint after the uicontrol statement and then click on the button Cancel that I created. I thought MATLAB would by default keep checking the push button to see if it has been clicked. I think the issue is that MATLAB does not check for the button until it has completed the remaining processes, and in this case the entire process may even take an hour which is why I kept a progressbar. I even tried creating the uicontrol push button in my main code instead of the function progressbar_auto, that still does not work. It seems that MATLAB recognizes the clicking of the button only if I click on Cancel right after it created a uicontrol for which I put a breakpoint, this is obviously not the way it should work. What should I do? Can anyone give me some advice on how to include a responsive cancel button on the progressbar for a long process?

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Answer 1

Titus Edelhofer 2013-11-9

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Hi,

You are right, if you have some lengthy code/calculation, Matlab queues the execution of the callback. Add to your code (e.g. in a loop at the end or anywhere else where it makes sense a call to drawnow. This will make matlab process the event queue and your callback should execute.

Titus

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Walter Roberson 2013-11-9

在 MATLAB Online 中打开

You currently have an existing loop....

   for variable = whatever
      get value from control
      if value indicates cancel, then break, end
      ...
   end

as your main controlling code.

Change that to

     for variable = whatever
      drawnow
      get value from control
      if value indicates cancel, then break, end
      ...
   end

abc 2013-11-10

I currently do not have a for loop to check the cancel button. I just have this :

hbutton=uicontrol('style','pushbutton','string','Cancel','Position', [550 0 100 20],'Callback',@Button_Callback);

Wont a for loop slow down the application? If it is necessary, how many iterations should it run. Also should it be within the function written for progressbar or in the main function which calls progressbar?

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