[Tkinter] Label doesn't refresh

[Tkinter] Label doesn't refresh - Printable Version

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Label doesn't refresh - jollydragon - Jul-10-2018

With below code, the label of directory path doesn't be refreshed correctly after I change the directory with "Ctrl+o".

E.g. When you change it to "C:\", you can see the new label is displayed on old label. How to refresh it to show the new label only?

I searched on the internet for 2 dys, no matter update(), destroy() or anything working in my Python v3.6.5.

import tkinter
import tkinter.filedialog
import os


class fileData:

     def __init__(self):
          self.targetDir = "./"
          self.mainWin = tkinter.Tk()

     def reportShow(self):          

          ln1 = 2
          tkinter.Label(self.mainWin, text = "     Target   ",justify = tkinter.LEFT).grid(row = ln1, column =0)
          absPath = os.path.abspath(self.targetDir)
          if len(absPath) > 40:  absPath = ' ...%s' % absPath[-37:]     
          tkinter.Label(self.mainWin, text = absPath, background='white').grid(row = ln1, column = 1, columnspan = 3)                    


def chooseFolder():                                                   #This is where we lauch the directory change bar
     filesData.targetDir = tkinter.filedialog.askdirectory(title = "Choose the target directory", initialdir=filesData.targetDir)
     filesData.reportShow()
     
 
     
def showMain():
     mainWin = filesData.mainWin
     
     winSize = 360     
     mainWin.geometry('%dx%d+%d+%d' % (winSize, winSize, (mainWin.winfo_screenwidth()-winSize)/2,
                    (mainWin.winfo_screenheight()-winSize)/2))        #The size and position of the main window
     mainWin.minsize(winSize,winSize)
     mainWin.bind('<Control-o>',lambda event: chooseFolder())

     filesData.reportShow()
     mainWin.mainloop()


filesData = fileData()


if __name__=="__main__":
    showMain()

RE: Label doesn't refresh - Axel_Erfurt - Jul-10-2018

it works by commenting the line

#          if len(absPath) > 40:  absPath = ' ...%s' % absPath[-37:]

There must be a problem with this line

RE: Label doesn't refresh - Larz60+ - Jul-10-2018

add to __init__

    self.abspathv = tkinter.StringVar()

Then modify Label:

tkinter.Label(self.mainWin, text = absPath, textvariable=self.abspathv, background='white').grid(row = ln1, column = 1, columnspan = 3)

and finally set it with:

self.abspath.set('vlaue goes here')

RE: Label doesn't refresh - jollydragon - Jul-11-2018

(Jul-10-2018, 10:41 AM)Axel_Erfurt Wrote: it works by commenting the line
#          if len(absPath) > 40:  absPath = ' ...%s' % absPath[-37:]  
There must be a problem with this line

Thanks for reminding. But why is it that line? How to modify?

(Jul-10-2018, 02:01 PM)Larz60+ Wrote: add to __init__

Thank you so much and it works. But why the variable "tkinter.StringVar()" must be defined in "__init__()"? Why can't in the function of class?

RE: Label doesn't refresh - Larz60+ - Jul-11-2018

It doesn't have to be in __init__.
This is a habit of mine as I tend to access from several methods, but it can be used in local scope.

RE: Label doesn't refresh - jollydragon - Jul-12-2018

(Jul-11-2018, 07:55 AM)Larz60+ Wrote: It doesn't have to be in __init__.
This is a habit of mine as I tend to access from several methods, but it can be used in local scope.

No, it doesn't work in local scope.
I moved it to local scope as the code below and you can try.
You'll find the label doesn't refresh correctly if changing the directory path from a long one to short.

import tkinter
import tkinter.filedialog
import os
 
 
class fileData:
 
     def __init__(self):
          self.targetDir = "./"
          self.mainWin = tkinter.Tk()
 
     def reportShow(self):          
 
          ln1 = 2
          absPathv = tkinter.StringVar()
          tkinter.Label(self.mainWin, text = "     Target   ",justify = tkinter.LEFT).grid(row = ln1, column =0)
          absPath = os.path.abspath(self.targetDir)
          if len(absPath) > 40:  absPath = ' ...%s' % absPath[-37:]
          absPathv.set(absPath)
          tkinter.Label(self.mainWin, textvariable = absPathv, background='white').grid(row = ln1, column = 1, columnspan = 3)                    
 
 
def chooseFolder():                                                   #This is where we lauch the directory change bar
     filesData.targetDir = tkinter.filedialog.askdirectory(title = "Choose the target directory", initialdir=filesData.targetDir)
     filesData.reportShow()
      
  
      
def showMain():
     mainWin = filesData.mainWin
      
     winSize = 360     
     mainWin.geometry('%dx%d+%d+%d' % (winSize, winSize, (mainWin.winfo_screenwidth()-winSize)/2,
                    (mainWin.winfo_screenheight()-winSize)/2))        #The size and position of the main window
     mainWin.minsize(winSize,winSize)
     mainWin.bind('<Control-o>',lambda event: chooseFolder())
 
     filesData.reportShow()
     mainWin.mainloop()
 
 
filesData = fileData()
 
 
if __name__=="__main__":
    showMain()

RE: Label doesn't refresh - Larz60+ - Jul-12-2018

And if it works in __init__ is what is the objection to keeping it there? It's still local to the class.

RE: Label doesn't refresh - jollydragon - Jul-13-2018

(Jul-12-2018, 12:21 PM)Larz60+ Wrote: And if it works in __init__ is what is the objection to keeping it there? It's still local to the class.

Got it and thank you very much.