How to set the text value content of an Entry widget using a button in tkinter

Question

I am trying to set the text of an Entry widget using a button in a GUI using the tkinter module   This GUI is to help me classify thousands of words into five categories  Each of the categories has a button  I was hoping that using a button would significantly speed me up and I want to double check the words every time otherwise I would just use the button and have the GUI process the current word and bring the next word   The command buttons for some reason are not behaving like I want them to  This is an example   import tkinter as tk from tkinter import ttk  win   tk Tk    v   tk StringVar   def setText word       v set word   a   ttk Button win  text  plant   command setText  plant    a pack   b   ttk Button win  text  animal   command setText  animal    b pack   c   ttk Entry win  textvariable v  c pack   win mainloop     So far  when I am able to compile  the click does nothing

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e  StringVar   def fileDialog        filename   filedialog askopenfilename initialdir       title    Select A      File  filetype      jpeg     jpg     png     png     All Files               e set filename  la   Entry self textvariable   e width   30  place x 230 y 330  butt Button self text  Browse  width 7 command fileDialog  place x 430 y 328

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One way would be to inherit a new class EntryWithSet  and defining set method that makes use of delete and insert methods of the Entry class objects   try                           In order to be able to import tkinter for     import tkinter as tk      either in python 2 or in python 3 except ImportError      import Tkinter as tk   class EntryWithSet tk Entry               A subclass to Entry that has a set method for setting its text to     a given string  much like a Variable class               def   init   self  master   args    kwargs           tk Entry   init   self  master   args    kwargs        def set self  text string                       Sets the object s text to text string                       self delete  0    end           self insert  0   text string    def on button click        import random  string     rand str      join random choice string ascii letters  for   in range 19       entry set rand str    if   name         main         root   tk Tk       entry   EntryWithSet root      entry pack       tk Button root  text  Set   command on button click  pack       tk mainloop

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You can choose between the following two methods to set the text of an Entry widget  For the examples  assume imported library import tkinter as tk and root window root   tk Tk        Method A  Use delete and insert  Widget Entry provides methods delete and insert which can be used to set its text to a new value  First  you ll have to remove any former  old text from Entry with delete which needs the positions where to start and end the deletion  Since we want to remove the full old text  we start at 0 and end at wherever the end currently is  We can access that value via END  Afterwards the Entry is empty and we can insert new text at position 0   entry   tk Entry root  new text    Example text  entry delete 0  tk END  entry insert 0  new text        Method B  Use StringVar  You have to create a new StringVar object called entry text in the example  Also  your Entry widget has to be created with keyword argument textvariable  Afterwards  every time you change entry text with set  the text will automatically show up in the Entry widget   entry text   tk StringVar   entry   tk Entry root  textvariable entry text  new text    Example text  entry text set new text        Complete working example which contains both methods to set the text via Button   This window    is generated by the following complete working example   import tkinter as tk  def button 1 click          define new text  you can modify this to your needs       new text    Button 1 clicked         delete content from position 0 to end     entry delete 0  tk END        insert new text at position 0     entry insert 0  new text   def button 2 click          define new text  you can modify this to your needs       new text    Button 2 clicked         set connected text variable to new text     entry text set new text   root   tk Tk    entry text   tk StringVar   entry   tk Entry root  textvariable entry text   button 1   tk Button root  text  Button 1   command button 1 click  button 2   tk Button root  text  Button 2   command button 2 click   entry pack side tk TOP  button 1 pack side tk LEFT  button 2 pack side tk LEFT   root mainloop

User · Answer

If you use a  text variable  tk StringVar    you can just set   that     No need to use the Entry delete and insert   Moreover  those functions don t work when the Entry is disabled or readonly   The text variable method  however  does work under those conditions as well   import Tkinter as tk       entryText   tk StringVar   entry   tk Entry  master  textvariable entryText   entryText set   Hello World

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Your problem is that when you do this   a   Button win  text  plant   command setText  plant      it tries to evaluate what to set for the command   So when instantiating the Button object  it actually calls setText  plant     This is wrong  because you don t want to call the setText method yet   Then it takes the return value of this call  which is None   and sets that to the command of the button   That s why clicking the button does nothing  because there is no command set for it   If you do as Milan Sk  la suggested and use a lambda expression instead  then your code will work  assuming you fix the indentation and the parentheses    Instead of command setText  plant    which actually calls the function  you can set command lambda setText  plant   which specifies something which will call the function later  when you want to call it   If you don t like lambdas  another  slightly more cumbersome  way would be to define a pair of functions to do what you want   def set to plant        set text  plant   def set to animal        set text  animal     and then you can use command set to plant and command set to animal - these will evaluate to the corresponding functions  but are definitely not the same as command set to plant   which would of course evaluate to None again

User · Answer

You might want to use insert method  You can find the documentation for the Tkinter Entry Widget here  This script inserts a text into Entry  The inserted text can be changed in command parameter of the Button  from tkinter import    def set text text       e delete 0 END      e insert 0 text      return  win   Tk    e   Entry win width 10  e pack    b1   Button win text  quot animal quot  command lambda set text  quot animal quot    b1 pack    b2   Button win text  quot plant quot  command lambda set text  quot plant quot    b2 pack    win mainloop

[python] How to set the text/value/content of an `Entry` widget using a button in tkinter

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