Key Event Handling using Tkinter in Python

Question

check the following link out :

[PyObjC Key Event Handling Question] Key Events Handling using PyObjC in Mac OS X

This was my initial question. I somehow managed to find a built-in plugin to solve the Key Event Management, but using Python. It is called Tkinter.

from Tkinter import *

root = Tk()
def screenshot(*ignore): os.system("screencapture -s %s" % check_snapshot) 
root.bind('<Return>', greet)
root.mainloop(  )

On pressing return (enter) key, it would successfully call screenshot function, and it would work.

Now, what I am looking for is, whenever I press combination of keys, like Command+Shift+4, the above function should be call.

This should be done in the same manner for Command+Shift+3 and Command+Shift+5 as well.

This should be done by checking which combination of keys are pressed, and accordingly, their respective screenshot functions should be called.

Also, this app shortcuts shouldn't be just relied on this app's window or frame, the window / frame of this window shouldn't be visible, yet, the shortcuts should work and trigger their respective functions.

root.withdraw()

This is the built-in function which hides the Tkinter window, but then, I am unable to invoke any of the functions. These functions only work on Tkinter window, or else, keys shortcuts don't work.

Any help would be appreciated.

Bryan Oakley · Accepted Answer · 2013-10-30 11:03:29Z

2

Tkinter events only work when the tkinter window has focus,and for it to have focus it must be visible. You cannot use tkinter to handle events while another program is in the foreground.

The format of an event is <modifier-modifier-event-detail>, with modifier and event being optional. Event is something like KeyPress, ButtonPress, ButtonRelease and so on. Detail gives more detail, such as which key, or which button. For example, <ButtonRelease-1> is for releasing mouse button 1 (one).

Modifier is where you specify control, alt, delete or shift, and you can have more than one. Shift is a bit special, because it is often interpreted by the OS before tkinter ever sees is. So, for example, "Shift-3" on an American English keyboard is "#". Thus, instead of <Shift-3> you would use <#>.

Putting that all together, command-shift-3 would be <Command-#>. However, if you do that on a Mac, it will intercept that event and do a screenshot, so the binding will only work on Windows and Linux. On each OS there are a few key bindings you cannot override.

The best description of the format to use for specifying events is the tcl/tk man page on bind. Even though you're asking about tkinter, the underlying engine is tcl/tk.

edited Oct 30, 2013 at 11:03

answered Oct 29, 2013 at 11:02

Bryan Oakley

389k53 gold badges582 silver badges739 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

user2927391 Over a year ago

hey Bryan, thanks for helping. I will have a look at it and try implementing it...if I am stuck again, would let you know..thanks ... :)

Collectives™ on Stack Overflow

Key Event Handling using Tkinter in Python

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related