How to make MATLAB detect keyboard stroke?

Hi,

I want to write a code which detect left and right arrow stroke in keyboard.

I tried to use below kind of code but it shows crosshair and also interrupts the working of other line. (Making crosshair invisible is somewhat important in this case)

[~,~,button]=ginput(1);
      switch button
          case 28 %left
          case 29 %right
       end

Is there any better way to do it? Thanks!

Answer 1

[Nirav Sharda]

There are a couple of ways to achieve this. You can use the KeyPressFcn callback on the figure window. Here is an example.

h_fig = figure;
set(h_fig,'KeyPressFcn',@myfun);

The myfun here could have something like this.

function myfun(src,event)
   disp(event.Key);
end

The other way to achieve this is to use ' waitforbuttonpress ' function. Here is an example code.

k = waitforbuttonpress;
% 28 leftarrow
% 29 rightarrow
% 30 uparrow
% 31 downarrow
value = double(get(gcf,'CurrentCharacter'))

I hope this helps.

[M Min]

Thanks! The last one works fine!

[Austin Susa]

I'm just commenting here so I can find this again. I've figured out how to make a button press affect another variable but I'm not good at making multiple things run at once. Also, Matlab keeps crashing. Pretty sure my laptop needs more RAM and that's the cause though. I'll probably just split my code into multiple Matlab files so I can test each part separately then figure out how to put them together later.

[Austin Susa]

Also, which numbers go along with the W and S keys

[Mathieu Möller]

w is 119 and s is 115.

[Joseph Rucker]

How do you find out what the numbers for the keys are?

[Caden Scharpf]

The numbers for the keys are their corresponding ASCII Charactershttps://www.petefreitag.com/cheatsheets/ascii-codes/

Answer 2

[balandong]

Maybe Im bit late to join the party. But you can consider this FEX submission KbTimer. It is MEX base thus quite fast