How to create a switch until released button in Matlab GUI

Hi, I am trying to create a button in the GUI where random numbers appear in the output as the user holds down a button.

I have used a toggle button with the code:

while get(hObject,'Value')
  disp(rand)
  pause(0.001)
end

This code works, but the output runs as the user presses the button and carries on until the button is pressed again.

How do i create a button where the code only loops while the button is being pressed down? As soon as the mouse click is released, the code stops executing

Answer 1

[Sean de Wolski]

There's not really a straight-forward way to do that. It can be done with a patch made to look like a uicontrol whose buttondownfcn changes the windowbuttonupfcn like in this example:

http://blogs.mathworks.com/pick/2008/05/27/advanced-matlab-capture-mouse-movement/

However, it would be better if it could just have a toggle button that when toggled stops:

http://blogs.mathworks.com/pick/2014/10/24/stop/

Answer 2

[matt dash]

As sean said, this is not an easy thing to do. The problem is that since your code is continually running in a loop, it is keeping matlab busy, and it can only be interrupted by an event on the java event dispatch thread. The reason your code with the toggle button works is that toggling a button is such an event.

But to get it to detect the mouse button being released is more complicated. I think you would need to set up a MouseListener in java. I dont think the windowbuttonupfcn method will work here since Matlab will be stuck in your while loop, it will never process the windowbuttonupfcn.