How to get progressbar start() info from one window (class) to other?

Question

There is a main window with menu and the progressbar. A correspondence window with OK button opens upon menu command and the OK button starts the process (here: 3 sec. sleep). The correspondence window is created via inheritance from a class I have not provided here (If required for answer, please let me know). The methods apply and ok override existing methods in the mother class.

Now my problem: Since the progressbar sits in the main window (class App) and progressbar(start) and progressbar(stop) in the correspondence window I somehow have to pass (start) and (stop) via the mother class tkSimpleDialog.Dialog to class App. So I thought I also override the __init__(self..) method, provide self. to progressbar.

How can I make this work?

import Tkinter, ttk, tkFileDialog, tkSimpleDialog, time, threading

class App:
  def __init__(self, master, progressbar):
    self.progress_line(master)

  def progress_line (self, master):
    self.progressbar = ttk.Progressbar(master, mode='indeterminate')
    self.progressbar.place(anchor = 'ne', height = "20", width = "150", x = "175", y = "30")

class AppMenu(object):

  def __init__(self, master, progressbar):
    self.master = master
    self.menu_bar()

  def menu_bar(self):
    menu_bar = Tkinter.Menu(self.master)
    self.menu_bar = Tkinter.Menu(self.master)
    self.master.config(menu=self.menu_bar)
    self.create_menu = Tkinter.Menu(self.menu_bar, tearoff = False)
    self.create_menu.add_command(label = "do", command = self.do)
    self.menu_bar.add_cascade(label = "now", menu = self.create_menu)

  def do(self):
    do1 = Dialog(self.master, progressbar)    

class Dialog(tkSimpleDialog.Dialog):

  def __init__(self, parent, progressbar):

    tkSimpleDialog.Dialog.__init__(self, parent, progressbar)
    self.transient(parent)

    self.parent = parent
    self.result = None

    self.progressbar = progressbar

    body = Frame(self)
    self.initial_focus = self.body(body)
    body.pack(padx=5, pady=5)

    self.buttonbox()
    self.grab_set()

    if not self.initial_focus:
        self.initial_focus = self

    self.protocol("WM_DELETE_WINDOW", self.cancel)
    self.geometry("+%d+%d" % (parent.winfo_rootx()+50, parent.winfo_rooty()+50))
    self.initial_focus.focus_set()
    self.wait_window(self)

  def ok(self, event=None):
    self.withdraw()
    self.start_foo_thread()
    self.cancel()
  def apply(self):
    time.sleep(5)

  def start_foo_thread(self):
    global foo_thread
    self.foo_thread = threading.Thread(target=self.apply)
    self.foo_thread.daemon = True
    self.progressbar.start()
    self.foo_thread.start()
    master.after(20, check_foo_thread)

  def check_foo_thread(self):
    if self.foo_thread.is_alive():
        root.after(20, self.check_foo_thread)
    else:
        self.progressbar.stop()    

master = Tkinter.Tk()
progressbar = None
app = App(master, progressbar)
appmenu = AppMenu(master, progressbar)
master.mainloop()

error messages: first after clicking ok:

Exception in Tkinter callback
Traceback (most recent call last):
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk/Tkinter.py", line 1410, in __call__
  File "ask-progressbar.py", line 57, in ok
    self.start_foo_thread()
  File "ask-progressbar.py", line 66, in start_foo_thread
    self.progressbar.start()
AttributeError: Dialog2 instance has no attribute 'progressbar'

second: after closing app

Exception in Tkinter callback
Traceback (most recent call last):
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk/Tkinter.py", line 1410, in __call__
  File "ask-progressbar.py", line 26, in do
    do1 = Dialog2(self.master, progressbar)
  File "ask-progressbar.py", line 33, in __init__
    self.transient(parent)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk/Tkinter.py", line 1652, in wm_transient
TclError: can't invoke "wm" command:  application has been destroyed

Answer 1

Below is a working version of your code. There were a number of issues I had to fix because you didn't change a number of things in the code from my answer to your other question about progressbars.

The answer to your main question here is basically that you have to pass the instance around and remember it when necessary in the various class instances involved so that their methods will have it available through theself argument when they need it. Also, the way you were trying to derive and override the tkSimpleDialog.Dialog base class methods was both over-complicated and incorrect as well.

Usually the best (and simplest) thing to do is just supply your own validate() and apply() methods since that's how it was designed to work. If you also need your own __init__() constructor, it's important to only pass parameters to the base class' method that it understands from within the one in the subclass. If you need more functionality, it can usually be provided via additional derived-class-only methods, that only it or other classes you've also created know about.

Anyway, here's what I ended-up with:

import Tkinter, ttk, tkFileDialog, tkSimpleDialog, time, threading

class App:
    def __init__(self, master):
        self.progress_line(master)

    def progress_line(self, master):
        # the value of "maximum" determines how fast progressbar moves
        self._progressbar = ttk.Progressbar(master, mode='indeterminate', 
                                            maximum=4) # speed of progressbar
        self._progressbar.place(anchor='ne', height="20", width="150", 
                                x="175", y="30")
    @property
    def progressbar(self):
        return self._progressbar # return value of private member

class AppMenu(object):
  def __init__(self, master, progressbar):
      self.master = master
      self.menu_bar()
      self.progressbar = progressbar

  def menu_bar(self):
      self.menu_bar = Tkinter.Menu(self.master)
      self.master.config(menu=self.menu_bar)
      self.create_menu = Tkinter.Menu(self.menu_bar, tearoff=False)
      self.create_menu.add_command(label="do", command=self.do)
      self.menu_bar.add_cascade(label="now", menu=self.create_menu)

  def do(self):
      Dialog(self.master, self.progressbar) # display the dialog box

class Dialog(tkSimpleDialog.Dialog):
    def __init__(self, parent, progressbar):
        self.progressbar = progressbar
        tkSimpleDialog.Dialog.__init__(self, parent, title="Do foo?")

    def apply(self):
        self.start_foo_thread()

    # added dialog methods...
    def start_foo_thread(self):
        self.foo_thread = threading.Thread(target=self.foo)
        self.foo_thread.daemon = True
        self.progressbar.start()
        self.foo_thread.start()
        master.after(20, self.check_foo_thread)

    def check_foo_thread(self):
        if self.foo_thread.is_alive():
            master.after(20, self.check_foo_thread)
        else:
            self.progressbar.stop()

    def foo(self): # some time-consuming function...
        time.sleep(3)


master = Tkinter.Tk()
master.title("Foo runner")
app = App(master)
appmenu = AppMenu(master, app.progressbar)
master.mainloop()

Hope this helps.

Answer 2

Here's another, simpler, solution that doesn't require the use of threading -- so could be easier to use/adapt in your case. It calls the progressbar widget's update_idletasks() method multiple times during the time-consuming foo() function. Again, it illustrates how to pass the progressbar around to the various parts of the code that need it.

import Tkinter, ttk, tkFileDialog, tkSimpleDialog, time

class App:
    def __init__(self, master):
        self.progress_line(master)

    def progress_line(self, master):
        self._progressbar = ttk.Progressbar(master, mode='indeterminate')
        self._progressbar.place(anchor='ne', height="20", width="150", 
                                x="175", y="30")
    @property
    def progressbar(self):
        return self._progressbar # return value of private member

class AppMenu(object):
    def __init__(self, master, progressbar):
        self.master = master
        self.menu_bar()
        self.progressbar = progressbar

    def menu_bar(self):
        self.menu_bar = Tkinter.Menu(self.master)
        self.master.config(menu=self.menu_bar)
        self.create_menu = Tkinter.Menu(self.menu_bar, tearoff=False)
        self.create_menu.add_command(label="do foo", command=self.do_foo)
        self.menu_bar.add_cascade(label="now", menu=self.create_menu)

    def do_foo(self):
        confirm = ConfirmationDialog(self.master, title="Do foo?")
        self.master.update() # needed to completely remove conf dialog
        if confirm.choice:
            foo(self.progressbar)

class ConfirmationDialog(tkSimpleDialog.Dialog):
    def __init__(self, parent, title=None):
        self.choice = False
        tkSimpleDialog.Dialog.__init__(self, parent, title=title)

    def apply(self):
        self.choice = True

def foo(progressbar):
    progressbar.start()
    for _ in range(50):
        time.sleep(.1) # simulate some work
        progressbar.step(10)
        progressbar.update_idletasks()
    progressbar.stop()

master = Tkinter.Tk()
master.title("Foo runner")
app = App(master)
appmenu = AppMenu(master, app.progressbar)
master.mainloop()