Alan Gauld wrote:
"Jim Byrnes" <jf_byr...@comcast.net> wrote in
When reading code examples I see things like
theframe.master.title('spam)
def __init__(self, master):
frame = Frame(master)
When I encounter these I tend to get bogged down trying to decide if
"master" has special meaning or is just a name the author has chosen.
In the first case master is an attribute of the frame and as
such is defined by the frame definition.
In the second case master is just an arbitrary name for a
parameter like any other. Because it is being used to correspond
to the master attribute of the Framer(as seen in the call to Frame() )
the author has used the name master too. But other common
names for the same attribute are parent, root, top, etc
For example is it similar to Buttton(text='spam) where text in this
case has special meaning.
In the first example yes, in the second no.
Although 'text' is even more special because it is actually defined in
the underlying Tk code rather than in Tkinter Python code.
I've goolged and found references to "widgets master attributes" but
nothing to really explain it. Could someone point me to a good
reference so that I could better understand it use.
Because Tkinter is a thin wrapper around the underlying Tk tookit
many atttributes of widgets are actually defined in the Tk code
and simply mirrored by Tkinter. In that sense the widget attributes
tend to have fixed names. But in Tkinter code the naming is
essentially arbitrary and follows the usual Python naming
conventions.
HTH,
Alan,
Sorry it took so long for me to get back to this issue. Thanks to you
and Steve for your replies.
I still am having trouble understanding the use of "master" in Tkinter.
I think the problem is I can't find any reference that explains the
concept around master, like the Button example I gave above. If I want
to put the word spam on a Button I found a reference that said you type
the word text followed by an equal sign followed by spam in quotes.
Let me try another example. The code snippet below comes from a working
example out of a book:
class CanvasEventsDemo(canvasDraw.CanvasEventsDemo):
def __init__(self, parent=None):
canvasDraw.CanvasEventsDemo.__init__(self, parent)
self.canvas.create_text(75, 8, text='Press o and r to move shapes')
self.canvas.master.bind('<KeyPress-o>', self.onMoveOvals)
self.canvas.master.bind('<KeyPress-r>', self.onMoveRectangles)
self.kinds = self.create_oval_tagged, self.create_rectangle_tagged
<snip>
The word master appears only twice in the entire script so it is not
defined somewhere else in the script. As an experiment I changed them
both to masterx. When I ran the script I got the following error:
Traceback (most recent call last):
File "canvasDraw_tags.py", line 41, in <module>
CanvasEventsDemo()
File "canvasDraw_tags.py", line 16, in __init__
self.canvas.masterx.bind('<KeyPress-o>', self.onMoveOvals)
AttributeError: Canvas instance has no attribute 'masterx'
So the Canvas does not have a masterx attribute but does have one called
master. Maybe the bottom line question is where can I look to see a
list of a widgets attributes?
Sorry to be so dense about this but I just don't get it yet.
Thanks, Jim
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