Mailman 3 August 2004 - Tkinter-discuss

Inserting a unicode zero-width nonbreaking space into a Text widget, from Tkinter, on a Mac
by Kenneth McDonald Nov. 3, 2004

Nov. 3, 2004

As the subject says, I am attempting to insert a particular unicode character (\ufeff) into a Text widget, from Python. This is not quite working correctly, and I'm not sure if the problem is between Python and Tcl, or is a problem of OS X not properly knowing the character. This character is supposed to be a 0-width space, and using Python's unicodedata.name function confirms that feff is in fact the proper unicode sequence. The character is construction using a one-character python string: zws = u"\ufeff" And then passed to Text's insert command. Unfortunately, what shows up on screen is a complex (perhaps Chinese) asian ideograph. "Python in a Nutshell" indicates that all communication between Tkinter and Tk is in unicode, so I had hoped this would transfer correctly. Not sure if I need to do some conversion or not...could there be a conflict between a straight Unicode (16-bit) representation and a UTF-8 representation? Or do I need to do an OS setting to make sure the OS and the internal representation are on the same wavelength? Thanks, Ken

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Please help -- Tkinter Scale widget with DoubleVar is acting weird
by Jared Cohen Aug. 23, 2004

Aug. 23, 2004

Hi all. I'm currently using a Tkinter Scale widget which uses a DoubleVar as its control variable. I then use the "trace_variable('w', callback)" method to invoke a callback whenever the DoubleVar changes. The problem is this: the callback is triggered when the slider moves (as it should), but it's also triggered when I just HOVER the mouse over the slider without clicking! Somehow or other, it must think that the control variable is being changed, even though it isn't. I *think* that this problem is related to the loss of precision that DoubleVars can have, but I'm not really sure. Has anyone else experienced this problem? How can I fix this? As an aid, here's a quick stub program that illustrates the problem. Try (for example) moving the slider to 0.3, release the mouse button, then move the mouse pointer back and forth over the slider WITHOUT clicking. Each time the pointer passes over the slider, it will print the value. import sys, Tkinter, types root = Tkinter.Tk() var = Tkinter.DoubleVar() def callback(*args): print var.get() var.trace_variable("w", callback) slider = Tkinter.Scale(root, from_ = 0.0, to = 1.0, resolution = 0.1, variable = var, orient = 'horizontal') slider.grid(sticky='ew') root.mainloop()

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Re: [Tkinter-discuss] Please help -- Tkinter Scale widget with DoubleVar is acting weird
by Jared Cohen Aug. 23, 2004

Aug. 23, 2004

Thanks to both of you for your help. I already do have mechanisms in place that prevent the callback from actually doing anything if the variable has not really been changed. But the problem with that method (and with both of your suggestions) is that even if the callback doesn't do anything, it is still getting invoked when it shouldn't be. I was simply trying to figure out WHY, because I felt that it would be more elegant to completely stop the callback from getting invoked incorrectly, than to allow it to be invoked and then have it return without doing anything. But if that's not feasible, then I'll just have to do it the other way :-)

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Hiding and unhiding frames and/or widgets in general
by Chris Nethery Aug. 22, 2004

Aug. 22, 2004

First, I recall now that I neglected to thank everyone for their help, concerning my last question. The last two months have been extraordinarily busy, although that's a poor excuse for bad manners, so thank you all, belatedly, for your assistance. I am back again, with another (possibly silly) question regarding hiding and unhiding windows. I notice that toplevel windows have the ability to be "withdrawn" or "deiconified" in order to be hidden from view. My widgets are not toplevel widgets, so I'm unclear about whether or not I can use these methods or not. Either way, I am trying (unsuccessfully) to accomplish something similar, in that I would like to destroy or withdraw an entryfield widget if a comboBox is displayed, and visa versa. Also, if neither an entryfield or a comboBox is displayed, nothing should be displayed in the same spot. The following code illustrates, to some degree, what I'm trying to accomplish. But you'll note that the code has other problems as well: import Pmw from Tkinter import * root = Tk() Pmw.initialise(root) class Stuff: def __init__(self, root): self.root = root self.mainframe = Frame(self.root) self.mainframe.pack(fill='both', expand=1, padx=5, pady=5) self.choices = [ '', 'Select the entryField...', 'Select the entryField again...', 'Select the entryField yet again...', ] self.choices2 = [ '', 'Select the comboBox...', 'Select the comboBox again...', 'Select the comboBox yet again...', ] self.stuffList = [ '', 'item 1', 'item 2', 'item 3', 'item 4', 'item 5', 'item 6', 'item 7', 'item 8', 'item 9', 'item 10', ] self.cBox = Pmw.ComboBox( self.mainframe, listheight=225, selectioncommand=self.createEntryField, entry_width=28, labelmargin=1, labelpos='w', label_text='Select stuff:', scrolledlist_items=self.choices+self.choices2) self.cBox.pack() self.eFrame = Frame(self.mainframe, borderwidth=0, width=200, height=22, relief=GROOVE) self.eField = Pmw.EntryField( self.eFrame, labelpos=W, label_text='Enter Stuff:', labelmargin=2, entry_width=12, validate = None, ) self.eField.pack() self.cFrame = Frame(self.mainframe, borderwidth=0, width=200, height=22, relief=GROOVE) self.cBox2 = Pmw.ComboBox( self.cFrame, listheight=165, entry_width=12, labelmargin=9, labelpos='w', label_text='Stuff:', scrolledlist_items=self.stuffList ) self.cBox2.pack() def createEntryField(self, hello): for item in self.choices: if self.cBox.component('entryfield').component('entry').get() == item: self.cFrame.lower() self.eFrame.lift() self.eFrame.place(relx=0.7, rely=0.08, anchor=NW) else: self.eFrame.lower() self.cFrame.lift() self.cFrame.place(relx=0.7, rely=0.08, anchor=NW) if __name__=='__main__': stuff = Stuff(root) root.mainloop() Any ideas? Thanking you in advance, Christopher Nethery

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