tkinter test field, scrolling, threads

Discussion in 'Python' started by Bob Greschke, Feb 27, 2004.

  1. Bob Greschke

    Bob Greschke Guest

    I have a program where the user pushes a button, a "starting" message is
    ..inserted to a text field with an associated scroll bar, a thread is started
    that inserts a "working..." message on to the end of the text field until
    stopped, or until the loop finishes. The loop sleeps for about 3 seconds
    every time through (I'm just prototyping at this point). The mainloop just
    waits for the user to hit the same button again which will set a flag and
    cause the thread to terminate early, otherwise it doesn't have anything to
    do. update()'s and update_idle_tasks() get called anytime anything is
    written to the text field. Everything works fine until the text field fills
    up then the program just freezes with no errors on the console window. If I
    change the starting of a thread to a regular function call then everything
    works fine.

    What is going wrong?

    Bob




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    Bob Greschke, Feb 27, 2004
    #1
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  2. Bob Greschke

    Eric Brunel Guest

    Bob Greschke wrote:
    > I have a program where the user pushes a button, a "starting" message is
    > .inserted to a text field with an associated scroll bar, a thread is started
    > that inserts a "working..." message on to the end of the text field until
    > stopped, or until the loop finishes. The loop sleeps for about 3 seconds
    > every time through (I'm just prototyping at this point). The mainloop just
    > waits for the user to hit the same button again which will set a flag and
    > cause the thread to terminate early, otherwise it doesn't have anything to
    > do. update()'s and update_idle_tasks() get called anytime anything is
    > written to the text field. Everything works fine until the text field fills
    > up then the program just freezes with no errors on the console window. If I
    > change the starting of a thread to a regular function call then everything
    > works fine.
    >
    > What is going wrong?


    If you do not post any code, it will be difficult for anyone to help you.
    Knowing your Python and tcl/tk versions and your platform will help too.

    I know that there are some issues regarding Tkinter and threads, but the
    following code works:

    --text+threads.py------------------
    from Tkinter import *
    import time, threading

    root = Tk()
    t = Text(root, width=8, height=4)
    t.pack(side=LEFT, fill=BOTH)
    vs = Scrollbar(root, orient=VERTICAL, command=t.yview)
    vs.pack(side=RIGHT, fill=Y)
    t.configure(yscrollcommand=vs.set)
    root.update()

    def thLoop():
    i = 0
    while 1:
    t.insert(END, 'spam %s\n' % i)
    i += 1
    time.sleep(1)

    th = threading.Thread(target=thLoop)
    th.setDaemon(1)
    th.start()

    root.mainloop()
    -----------------------------------

    Tested with Python 2.1.1, tcl/tk 8.3.2 on Linux Mandrake 8.0
    --
    - Eric Brunel <eric dot brunel at pragmadev dot com> -
    PragmaDev : Real Time Software Development Tools - http://www.pragmadev.com
    Eric Brunel, Mar 1, 2004
    #2
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