Re: Trouble calling method from one class to another class

(1) I added os.getcwd()

(2) I modified self.tab_num per my understanding of your explanation.

(3) I added: frame.add_tab_page() but it gives the error: NameError: name 
'frame' is not defined.
How would class MyTreeCtrl know about 'frame'? Do I have to pass it in as a 
parameter?

(4) zip file attached as v4.3

Thank you...

On Sunday, April 25, 2021 at 1:58:34 PM UTC-7 johnf wrote:

> I guess I confused you.  The self.tab_num within the class constructor/def 
> is just fine. Recall I would not do that.  I would have initialized a 
> counter outside of my class.
>
> CoreFrame is a class constructor or a definition of some object.  It is 
> NOT the object!  You defined the var within the class constructor and it 
> will work.  Therefore any instance of the class CoreFrame will contain the 
> var tab_num and the start value is one (1).   The only instance of 
> CoreFrame is named "frame" in your code.  'frame' is the object and it 
> contains a var tab_num.  This happens when you do:
>
> frame = CoreFrame()  frame is now an object as described by the class 
> constructor CoreFrame.  You did that in "__main__".
>
> An easy fix to your current code "tab_num" issue would be to use 
>
>  self.tab_num = 1 in the CoreFrame->__init__
>
> and in your class MyTreeCtrl to use
>
> frame.add_tab_page() and NOT CoreFrame.add_tab_page(CoreFrame) in the 
> on_tree_single_click method.
>
> Just because it is an easy fix does mean it is good code - I don't think 
> it is.
>
> Also make it easier for others to test your code by at least not hard 
> coding a path to some file structure on your computer - maybe use 
> os.getcwd()
>
> Johnf
>
>
>
>
>
>
> On 4/25/21 11:32 AM, RF wrote:
>
> Thank you John for your comments. One at a time if I may.
>
> > The "tab_num" has some logic issues ...
>
> Well, I changed line 67: self.tab_num = 1
> to
> frame.tab_num = 1
> and got: NameError: name 'frame' is not defined.
>
> I'm thinking about this one...I must not have understood you 
> correctly...the instance was created in line 95 and must not be 'global' 
> since line 67 is complaining about it.
>
> I'm attaching my current pyCore4.py file as pyCore4.2.py (zipped). Line 
> 67 is the only change: frame.tab_num = 1 
>
> On Saturday, April 24, 2021 at 5:36:19 PM UTC-7 johnf wrote:
>
>> Python code has default values. In this case you don't have to pass any 
>> parameters to init the class for it to create an instance of the class.  Of 
>> course at some point those values will be needed.  That said, your code is 
>> needs the parameters:
>>
>> super().__init__(parent, id = id, pos= position, size = size, style=style)
>>
>> You are subclassing the wx.TreeCtrl class and you need to pass those 
>> parameters.  In the case of the Geeksforgeeks code they created an instance 
>> of the wx.TreeCtrl class directly (you could have also done the same).  
>> They passed the parameters that were needed for their project and wxPython 
>> defaulted the rest.  BTW I'm not sure but I bet the underlining c++ code 
>> has multi-def of the code to allow passing all the parameters - all, some  
>> or none.
>>
>> The "tab_num" has some logic issues.  In the instance of the CoreFrame 
>> you create a var "self.tab_num" with the value of one (1).  But what is the 
>> name of the CoreFrame instance?  You named it "frame".  Therefore, any time 
>> you want to determine value of "tab_num" you would NOT use the following:
>>
>> CoreFrame.tab_num
>>
>> you would use 
>>
>> frame.tab_num.
>>
>> Why"  Because the class name is CoreFrame and it is not the instance of 
>> the class.  The instance of the class is 'frame".
>>
>> BTW in general I never do as you did above.  Adding the var and allowing 
>> it to increment within the instance will only apply to the one instance in 
>> this case "frame".  The moment you create a second instance of CoreFrame 
>> the value of "tab_num" will start over.  Of course maybe that is what you 
>> wanted.
>>
>> Also in your "add_tab_page" method you set yourself to fail.  It only 
>> works the first time.  When you call from outside the instance there is no 
>> self.tab_num.
>>
>> I'll let you think about how to fix that - there several ways!
>>
>> Johnf
>>
>>
>>
>>
>>
>> On 4/24/21 4:32 PM, RF wrote:
>>
>> John, thank you for those comments. I've looked at the __init__ docs and 
>> have adjusted accordingly.
>>
>> One comment re the TreeCtrl __init__: I see in some examples I have 
>> looked at that they don't include all the parameters and their code runs 
>> without giving any errors. For example, this website: 
>> https://www.geeksforgeeks.org/wxpython-treectrl/
>>
>> I don't understand why their codding example runs without error as they 
>> have omitted the style, validator and name. In any event, I followed your 
>> advice and patterned my __init__ after the options shown in the docs. 
>> However, I did make one exception: I omitted the TreeCtrl validator 
>> argument as I don't think I need it in the __init__. The line seems to 
>> execute OK without and I still am not sure it's optional as the __init__ 
>> docs show it in there. So I guess it is optional? Geeksforgeeks omitted 
>> three of the arguments and I didn't get any errors when I ran their example 
>> code.
>>
>> I'm attaching pyCode4.py as the update with my changes (based on your 
>> comments).
>>
>> > At this point I stopped because the GUI opened and I'm not sure what 
>> you are trying to d.
>> At this point, I am just trying to execute the file without getting the 
>> error: AttributeError: type object 'CoreFrame' has no attribute 'tab_num' 
>> on line 78.
>> Then I want to click on any tree node just to fire the add_tab_page() 
>> method and see that a new tab page is created.
>>
>>
>> On Sat, Apr 24, 2021 at 3:43 PM john fabiani <[email protected]> wrote:
>>
>>> Take my advise with a smile because I am NOT the best programmer.  But, 
>>> I have to say this is some very confusing code pxCore2.py.  I believe you 
>>> do not have a handle on how OOP works within python. Also you copied code 
>>> directly out of the wxPython demo but lacked the understanding of what was 
>>> being presented.  And I bet this is causing confusion and is also not 
>>> allowing you to move forward.
>>>
>>> When you define a class, you don't normally create an instance of the 
>>> class within the definition of the class.
>>>
>>> self._MyTreeCtrl = MyTreeCtrl is in the __init__ method of MyTreeCtrl.  
>>>
>>> so comment out "self._MyTreeCtrl = MyTreeCtrl"
>>>
>>> I believe with wxPython 4.x the super() is used.
>>>
>>> so
>>>
>>> wx.TreeCtrl.__init__(self, parent, id, position, size, style)
>>>
>>> is now 
>>>
>>> super().__init__(parent, id = id, pos= position, size = size, 
>>> style=style)
>>>
>>> You can review the what is needed to init wx.TreeCtrl by looking at the 
>>> method in the source code.  In this case there are two signatures:
>>>
>>>  TreeCtrl()
>>>
>>> or  TreeCtrl(parent, id=ID_ANY, pos=DefaultPosition, size=DefaultSize, 
>>> style=TR_DEFAULT_STYLE, validator=DefaultValidator, name=TreeCtrlNameStr)
>>>
>>> Therefore, depending on your needs you could just use:
>>>
>>> super().__init__()
>>>
>>> At this point I stopped because the GUI opened and I'm not sure what you 
>>> are trying to do.  If it is to list a directory there is a widget called 
>>> 'FileDialog'.
>>>
>>> Johnf
>>>
>>>
>>>
>>>
>>>
>>> On 4/24/21 10:01 AM, RF wrote:
>>>
>>>
>>> I'm attaching my small demo test app. I'm having a heck of a time 
>>> figuring out how to call add_tab_page() from the MyTreeCtrl class. This 
>>> should happen when I just click on a tree node. While this doesn't seem to 
>>> make any sense, what I plan to do with this action is open a new notebook 
>>> tab and load in the filename into the new tab. But I have to get past this 
>>> first: being able to call the add_tab_page() from the MyTreeCtrl class.
>>>
>>> I'm fairly sure I'm missing something small here.
>>>
>>> Thank you for any help.
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>>
>>
>> -- 
>> Ralph Freshour
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