[Tutor] How to access a method defined in one class from another class (which is a thread) in Python3?

[SM]

Hi Alan,
Thanks, very much, for your time answering my question. I ended up using
global variables for all the attributes I had to share between the
MainWindow class and the thread, and it worked. I am sure there are better
alternatives, but since it was just a couple of attributes, the code looks
ok.
Some responses  in line at [SM]

On Sun, Aug 11, 2013 at 12:05 PM, Alan Gauld <alan.gauld at btinternet.com>wrote:

> On 09/08/13 16:50, SM wrote:
>
> Sorry I only just picked this up.
>
>
>  (ex: self.tab_fw = QtGui.QWidget(), self.tab_ann = QtGui.QWidget(),
>> etc), its own textEdit window and its own progress bar widget.
>> All the tabs are defined within this single class - they are not
>> instances of the class, as the tabs are distinct from each other. All of
>> that is working really well.
>>
>
> OK, I'll assume the structure looks like
>
> MainGUIWindow
> - Tab1
>   - TextEdit1
>   - ProgressBar1
>   - any other widgets on tab1
> - Tab2
>   - TextEdit2
>   - ProgressBar2
>   - any other widgets on tab2
> - Tab3
>   - TextEdit3
>   - ProgressBar3
>   - any other widgets on tab3
>
[SM] Yes

>
> And that both the TextEdit and progress bar widgets are part of
> the Qt framework/library? So there are 3 distinct progress bar instances,
> one per tab?


[SM]: Yes, that is right.

>
>
>          an added feature, I am now asked to have a "progress bar" widget
>>         which appears when an operation is going on, to tell the user that
>>         he/she has to wait.
>>
>
> Is this an extra (4th?) progress bar or is this the ones already described
> as being in the tabs?
>

[SM] The latter. There are just 3 tabs and 3 progress bars

>
> Also, when you say "appears" do you mean its invisible until the operation
> starts? Or is it visible but inactive (maybe greyed out?)

[SM] Wrong choice of word on my part.  I should have said, " widget which
swings horizontally"

>
>
>  [SM]: Yes. I shouldn't say duplicated, but each tab has a different
>> progress bar of its own. In the example, I was quoting the code for just
>> on tab. The others will be implemented similarly.
>>
>
> OK So I'm again going to assume:
>
> A total of 1 progress bar per tab. The "added feature" is what these bars
> are addressing?

[SM]: yes

>
>
>          So I am running two threads - first one is the progressbar
>>         widget which has a rectangular slab spinning sideways to
>>         indicate that the operation is going on.
>>
>
> I usually expect a progress bar to indicate the percentage complete but
> this sounds like its just a spinning eggshell activity indicator. Is that
> correct? You have no progress value indication?


[SM] Yes, it is more of a egg-whatever.... It just spins horizontally as
opposed to showing the percentage of work done. That is part of the
requirement.

>
>
>  The second thread is the one which is actually doing the operation.
>>
> > I have a flag that the second thread sets after the job is done
>
> OK, again I'll assume we are dealing with just an activity indicator not a
> value display.


[SM] yes

>
>
>          and stops spinning and gets out of the loop when the flag is set.
>>  I
>>         have that working as well.
>>
>
> OK, Good the picture is building.
>
>
>  [SM]: I did start out with a timer. But due to my lack of experience
>> with usage of timer in Python, the code I wrote was running sequentially
>>
>
> That sounds like you tried to use a Python native timer. Normally in a GUI
> the toolkit (Qt in this case) provides a timer event that triggers
> via the normal event mechanism. You set the timer, the event arrives and
> you do something then reset the timer for the next time round.
>
> I found this page that describes the Qt approach (which includes
> multi-shot timers) and links to more detailed examples etc.
>
> http://qt-project.org/doc/qt-**4.7/timers.html#id-fd46b213-**
> 376e-4636-a7d2-8ae899de1e11<http://qt-project.org/doc/qt-4.7/timers.html#id-fd46b213-376e-4636-a7d2-8ae899de1e11>
>

[SM] Thanks, very much, for the link. I will go over it. In my opinion, if
the timer works, using it is less complicated than using threads.

Thanks!
-SM

>
> The code is in C++ but should translate easily to python and PyQt.
>
> HTH
>
> --
> Alan G
> Author of the Learn to Program web site
> http://www.alan-g.me.uk/
>
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