Tkinter threads

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February 18th, 2004, 07:22 AM

Wizard2003

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Tkinter threads

Does anybody know how to synchronize Tkinter threads?
I tried to build a tk widget with and OK button. When the button is pressed the widget should be destroyed and a function from an other module should be invoked.

Code:

[...]
def okPressed(self, event=None):
  self.quit()
  <mymodule>.<myfunction> (<myparams>)
[...]

Now the problem is that <myfunction> is be invoked but the widget is not destroyed until the function returns.
I guess the destroy call is put into a message queue and is processed when the function returns.

Is there a way to synchronize the calls?

February 18th, 2004, 07:59 AM

Strike

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Quote:

Originally Posted by Wizard2003

Code:

[...]
def okPressed(self, event=None):
  self.quit()
  <mymodule>.<myfunction> (<myparams>)
[...]

Is there a reason you are threading your app? Part of the reason GUIs are event-based is so the framework can worry about handling multiple events and synchronicity. If you do use threading in a GUI app, you generally don't put stuff that would affect any of the other portions of code in it, just stuff that you don't want to block on.

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February 18th, 2004, 04:41 PM

Grim Archon

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The following code builds up a window, if you click Quit it finishes, if you click Repeat it destroys itself but gets rebuilt.

Code:

from Tkinter import *
class App:

    def __init__(self, master):
        self.master = master
        self.again = False
        self.button = Button(master, text="QUIT", fg="red", command=self.quit)
        self.button.pack(side=LEFT)
        self.hi_there = Button(master, text="Repeat", command=self.repeat)
        self.hi_there.pack(side=LEFT)

    def quit(self):
        self.master.destroy()
        
    def repeat(self):
        self.again = True
        self.quit()

while True:
    root = Tk()
    app = App(root)
    root.mainloop()
    if not app.again:
        break

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February 18th, 2004, 04:47 PM

Grim Archon

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This example is similar to the last but uses a wait loop on a child window. The advantage in this code is that the main window remains open even though the child is destroyed and then rebuilt.

Code:

from Tkinter import *
again = False
class App:
    def __init__(self, master):
        global again
        self.master = master
        again = False
        self.quit_button = Button(self.master, text="QUIT", fg="red", command=self.quit)
        self.quit_button.pack(side=LEFT)
        self.rep_button = Button(self.master, text="Repeat", command=self.repeat)
        self.rep_button.pack(side=LEFT)
        
    def wait(self):
        self.master.wait_window()
        
    def quit(self):
        self.master.destroy()
        
    def repeat(self):
        global again
        again = True
        self.quit()

root = Tk()
while True:
    mywin = Toplevel()
    app = App(mywin)
    app.wait()
    if not again:
        break
root.mainloop()

One of these examples should apply to your problem

.
Grim

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