Detect Keyboard Input Matlab

Question

I have a simple question, although it's harder than it seems; I couldn't find the answer on the interwebs :O

I'm writing a script in Matlab. What I want to do is the following:

• When I press the esc key, I want a helpdialogue to pop up, so my script pauses. (So when I press esc, I want to stop the whole script to run so that the car (which im writing the script for) stops driving)

How do I do this? How can I say to Matlab: When I press esc, do this...

Thanks for your time guys!

EDIT: It's no option to implement something which awaits the keypress. Im writing a script for a driving car. It just has to drive around basically, but when I press esc for example, it should stop driving. So the script just has to run, untill I press the esc key; then the script has to pause.

Answer 1

KeyPressFcn is good because it forces you to write event-driven code. Which is generally a good idea! However, if KeyPressFcn doesn't seem right for you, for example if you must keep running in a loop, and you just want to poll whether a key has been pressed, I found this solution buried in the matlab website:

get(gcf,'CurrentCharacter')

Then you could set this property to a blank, and poll it as required. e.g:

finish=false;
set(gcf,'CurrentCharacter','@'); % set to a dummy character
while ~finish
  % do things in loop...

  % check for keys
  k=get(gcf,'CurrentCharacter');
  if k~='@' % has it changed from the dummy character?
    set(gcf,'CurrentCharacter','@'); % reset the character
    % now process the key as required
    if k=='q', finish=true; end
  end
end

This worked well for me in 2014b. The downside is that the graphics window needs to be focused to receive the key events.