Develop Reference

Changing one scale widget will change the secone one

I have two scale widgets in my code that are supposed to display values from a list. I want to be able to set individual values for both sliders. For example, for file 1 "2.4" and for file 2 "5.025". But currently I can only update the second (lower) slider without it triggering the first (upper) one. If I use the upper one, the value of the second one is also changed.
I'm stuck implementing the lambda function, so it would be create if some could give me a hint.
Thanks!
import tkinter as tk
class File_Selection():
def __init__(self, frame, text):
self.frame = frame
self.text = text
self.label_file = tk.Label(self.frame, text=text)
self.label_file.pack(side="left", anchor="s")
self.label_test = tk.Label(self.frame, text="| Select value: ")
self.label_test.pack(side="left", anchor="s")
self.scale = tk.Scale(self.frame, orient=tk.HORIZONTAL, from_=0)
self.scale.pack(side="left", anchor="s")
class View:
def __init__(self, view):
self.view = view
self.frame = tk.Frame(self.view)
self.frame.pack()
self.frame_row1 = tk.Frame(self.frame)
self.frame_row1.pack(side="top")
self.frame_row2 = tk.Frame(self.frame)
self.frame_row2.pack(side="top")
self.file_one = File_Selection(self.frame_row1, "File 1")
self.file_two = File_Selection(self.frame_row2, "File 2")
class Controller:
def __init__(self):
self.root = tk.Tk()
self.view = View(self.root)
self.values = [1.01,2.4,3.6,4.89,5.025,6.547]
self.view.file_one.scale.bind('<Enter>', self.update_scale)
self.view.file_two.scale.bind('<Enter>', self.update_scale)
def run(self):
self.root.mainloop()
def update_scale(self, event):
self.active_scales = [self.view.file_one.scale, self.view.file_two.scale]
for scale in self.active_scales:
scale.config(from_=min(self.values), to=max(self.values), resolution=0.001, command=lambda value=scale: self.set_scale(value, scale))
def set_scale(self, value, scale):
self.newvalue = min(self.values, key=lambda x: abs(x-float(value)))
scale.set(self.newvalue)
if __name__ == "__main__":
c = Controller()
c.run()

The problem is that you have both scales set to active_scales. You can take advantage of the event and do away with active_scales.
You can get the widget associated with an event with event.widget. So, you can change the update_scales function from
def update_scale(self, event):
self.active_scales = [self.view.file_one.scale, self.view.file_two.scale]
for scale in self.active_scales:
scale.config(from_=min(self.values), to=max(self.values), resolution=0.001, command=lambda value=scale: self.set_scale(value, scale))
to
def update_scale(self, event):
event.widget.config(from_=min(self.values), to=max(self.values), resolution=0.001, command=lambda value=event.widget: self.set_scale(value, event.widget))
Additionally, since self.values don't appear to change, it does not seem necessary to config each scale to change its bounds and resolution on each event. You can instead pull that out of the event and make you Controller class as follows.
class Controller:
def __init__(self):
self.root = tk.Tk()
self.view = View(self.root)
self.values = [1.01,2.4,3.6,4.89,5.025,6.547]
self.view.file_one.scale.bind('<Enter>', self.update_scale)
self.view.file_two.scale.bind('<Enter>', self.update_scale)
self.view.file_one.scale.config(from_=min(self.values), to=max(self.values), resolution=0.001)
self.view.file_two.scale.config(from_=min(self.values), to=max(self.values), resolution=0.001)
def run(self):
self.root.mainloop()
def update_scale(self, event):
event.widget.config(command=lambda value=event.widget: self.set_scale(value, event.widget))
def set_scale(self, value, scale):
self.newvalue = min(self.values, key=lambda x: abs(x-float(value)))
scale.set(self.newvalue)

Python Tkinter buttons don't pass the right argument? [duplicate]

This question already has an answer here:
Passing argument to a function via a Button in Tkinter, starnge behaviour in loop [duplicate]
(1 answer)
Closed 4 years ago.
I'm trying to make a simple interface with 3 buttons, and each button should trigger an action based on its label. However, even though (I think) I'm passing the correct argument, it always passes the label of the last button. Here's a stripped-down version to show what's happening:
import tkinter as tk
import random
class Application(tk.Frame):
def __init__(self, window=None):
super().__init__(window)
self.labels = ['Washington','London','Paris','Rome','Berlin','Madrid']
self.buttons = [tk.Button(self),tk.Button(self),tk.Button(self)]
self.pack()
for k,button in enumerate(self.buttons):
button.config(width=10)
button.grid(row=0, column=k)
self.update_buttons()
def update_buttons(self):
labels = list(random.sample(self.labels,3))
random.shuffle(labels)
for label,button in zip(labels,self.buttons):
button["text"] = label
button["command"] = lambda: self.verify(label)
def verify(self, label):
print(f'You pressed the button with label {label}')
self.update_buttons()
window = tk.Tk()
app = Application(window=window)
app.mainloop()
Why?

You are encountering a (late biding) closure problem.
When you create a function using lambda, a closure is created. This means the variables in function's body are looked up at the time you call the lambda, not when you create it (and the scope in which lambda was created will contain variable with the final value that was assigned).
In order to prevent this, you need to create an argument and set it to a default value, which stores the current value of the variable at creation time.
import tkinter as tk
import random
class Application(tk.Frame):
def __init__(self, window=None):
super().__init__(window)
self.labels = ['Washington','London','Paris','Rome','Berlin','Madrid']
self.buttons = [tk.Button(self),tk.Button(self),tk.Button(self)]
self.pack()
for k,button in enumerate(self.buttons):
button.config(width=10)
button.grid(row=0, column=k)
self.update_buttons()
def update_buttons(self):
labels = list(random.sample(self.labels,3))
random.shuffle(labels)
for label,button in zip(labels,self.buttons):
button["text"] = label
button["command"] = lambda label=label: self.verify(label) # Here
def verify(self, label):
print(f'You pressed the button with label {label}')
self.update_buttons()
window = tk.Tk()
app = Application(window=window)
app.mainloop()
You can also use functools.partial, which looks cleaner in my opinion:
import tkinter as tk
import random
from functools import partial
class Application(tk.Frame):
def __init__(self, window=None):
super().__init__(window)
self.labels = ['Washington','London','Paris','Rome','Berlin','Madrid']
self.buttons = [tk.Button(self),tk.Button(self),tk.Button(self)]
self.pack()
for k,button in enumerate(self.buttons):
button.config(width=10)
button.grid(row=0, column=k)
self.update_buttons()
def update_buttons(self):
labels = list(random.sample(self.labels,3))
random.shuffle(labels)
for label,button in zip(labels,self.buttons):
button["text"] = label
button["command"] = partial(self.verify, label)
def verify(self, label):
print(f'You pressed the button with label {label}')
self.update_buttons()
window = tk.Tk()
app = Application(window=window)
app.mainloop()

You need to assign a parameter to the lambda function, and pass it as argument to the function.
import tkinter as tk
import random
class Application(tk.Frame):
def __init__(self, window=None):
super().__init__(window)
self.labels = ['Washington','London','Paris','Rome','Berlin','Madrid']
self.buttons = [tk.Button(self),tk.Button(self),tk.Button(self)]
self.pack()
for k,button in enumerate(self.buttons):
button.config(width=10)
button.grid(row=0, column=k)
self.update_buttons()
def update_buttons(self):
labels = list(random.sample(self.labels,3))
random.shuffle(labels)
for label,button in zip(labels,self.buttons):
button["text"] = label
button["command"] = lambda lbl=label: self.verify(lbl) # <-- here
def verify(self, label):
print(f'You pressed the button with label {label}', flush=True) # <-- added flush=True to ensure the printing is done as the moment you click
self.update_buttons()
window = tk.Tk()
app = Application(window=window)
app.mainloop()

Receiveing input from Python's tkinter entry widget and displaying it in a label

The program I am working with currently requires input from the user to be displayed on the programs window. I have researched on both the internet and stackoverflow, discovering several solutions to my problem, but none seem to work. My goal is to receive input from the user via Python's tkinter entry widget and display the results in a new label, while taking out my initial one and the entry box, however, the program is rejecting my attempts at an answer.
What strategy, lines of code/library's, or pieces of advice do you have for me to accomplish my goal?
My existing solutions:
.get()
textvariable=self.entdat
Existing code is as follows:
from Tkinter import *
import time
class Input(Frame):
def __init__(self, parent=None, **kw):
Frame.__init__(self, parent, background="white")
self.parent = parent
self.initUI()
self.entdat = StringVar
self.timestr = StringVar()
self.makeWidgets()
def makeWidgets(self):
self.ol = Label(text="Objective:")
self.ol.pack(side=TOP)
self.ew = Entry()
self.ew.pack(side=TOP)
self.b = Button(text="OK", command=self.clicked)
self.b.pack(side=TOP)
def clicked(self):
self.entdat = self.ew.get()
self.dat = Label(textvariable=self.ew.get())
self.dat.pack(side=TOP)
self.hide_Widget()
def hide_Widget(event):
event.ew.pack_forget()
event.ol.pack_forget()
event.b.pack_forget()
def main():
root = Tk()
root.geometry("240x135+25+50")
tm = Input(root)
tm.pack(side=TOP)
root.mainloop()
if __name__ == '__main__':
main()

I amended your code, so that it executes at least, and hopefully in a way you want.
from Tkinter import *
class Input(Frame):
def __init__(self, parent=None, **kw):
Frame.__init__(self, parent, background="white")
self.parent = parent
self.entdat = StringVar()
self.makeWidgets()
def makeWidgets(self):
self.ol = Label(text="Objective:")
self.ol.pack(side=TOP)
self.ew = Entry(textvariable=self.entdat)
self.ew.pack(side=TOP)
self.b = Button(text="OK", command=self.clicked)
self.b.pack(side=TOP)
def clicked(self):
self.dat = Label(self, textvariable=self.entdat )
self.dat.pack(side=TOP)
self.distroy_Widget()
def distroy_Widget(self):
self.ew.destroy()
self.ol.destroy()
self.b.destroy()
def main():
root = Tk()
root.geometry("240x135+25+50")
tm = Input(root)
tm.pack(side=TOP)
root.mainloop()
if __name__ == '__main__':
main()
Hope it helps.

Display message when hovering over something with mouse cursor in Python

I have a GUI made with TKinter in Python. I would like to be able to display a message when my mouse cursor goes, for example, on top of a label or button. The purpose of this is to explain to the user what the button/label does or represents.
Is there a way to display text when hovering over a tkinter object in Python?

I think this would meet your requirements.
Here's what the output looks like:
First, A class named ToolTip which has methods showtip and hidetip is defined as follows:
from tkinter import *
class ToolTip(object):
def __init__(self, widget):
self.widget = widget
self.tipwindow = None
self.id = None
self.x = self.y = 0
def showtip(self, text):
"Display text in tooltip window"
self.text = text
if self.tipwindow or not self.text:
return
x, y, cx, cy = self.widget.bbox("insert")
x = x + self.widget.winfo_rootx() + 57
y = y + cy + self.widget.winfo_rooty() +27
self.tipwindow = tw = Toplevel(self.widget)
tw.wm_overrideredirect(1)
tw.wm_geometry("+%d+%d" % (x, y))
label = Label(tw, text=self.text, justify=LEFT,
background="#ffffe0", relief=SOLID, borderwidth=1,
font=("tahoma", "8", "normal"))
label.pack(ipadx=1)
def hidetip(self):
tw = self.tipwindow
self.tipwindow = None
if tw:
tw.destroy()
def CreateToolTip(widget, text):
toolTip = ToolTip(widget)
def enter(event):
toolTip.showtip(text)
def leave(event):
toolTip.hidetip()
widget.bind('<Enter>', enter)
widget.bind('<Leave>', leave)
The widget is where you want to add the tip. For example, if you want the tip when you hover over a button or entry or label, the instance of the same should be provided at the call time.
Quick note: the code above uses from tkinter import *
which is not suggested by some of the programmers out there, and they have valid points. You might want to make necessary changes in such case.
To move the tip to your desired location, you can change x and y in the code.
The function CreateToolTip() helps to create this tip easily. Just pass the widget and string you want to display in the tipbox to this function, and you're good to go.
This is how you call the above part:
button = Button(root, text = 'click mem')
button.pack()
CreateToolTip(button, text = 'Hello World\n'
'This is how tip looks like.'
'Best part is, it\'s not a menu.\n'
'Purely tipbox.')
Do not forget to import the module if you save the previous outline in different python file, and don't save the file as CreateToolTip or ToolTip to avoid confusion.
This post from Fuzzyman shares some similar thoughts, and worth checking out.

You need to set a binding on the <Enter> and <Leave> events.
Note: if you choose to pop up a window (ie: a tooltip) make sure you don't pop it up directly under the mouse. What will happen is that it will cause a leave event to fire because the cursor leaves the label and enters the popup. Then, your leave handler will dismiss the window, your cursor will enter the label, which causes an enter event, which pops up the window, which causes a leave event, which dismisses the window, which causes an enter event, ... ad infinitum.
For simplicity, here's an example that updates a label, similar to a statusbar that some apps use. Creating a tooltip or some other way of displaying the information still starts with the same core technique of binding to <Enter> and <Leave>.
import Tkinter as tk
class Example(tk.Frame):
def __init__(self, *args, **kwargs):
tk.Frame.__init__(self, *args, **kwargs)
self.l1 = tk.Label(self, text="Hover over me")
self.l2 = tk.Label(self, text="", width=40)
self.l1.pack(side="top")
self.l2.pack(side="top", fill="x")
self.l1.bind("<Enter>", self.on_enter)
self.l1.bind("<Leave>", self.on_leave)
def on_enter(self, event):
self.l2.configure(text="Hello world")
def on_leave(self, enter):
self.l2.configure(text="")
if __name__ == "__main__":
root = tk.Tk()
Example(root).pack(side="top", fill="both", expand="true")
root.mainloop()

You can refer to this- HoverClass
It is exactly what you need. Nothing more, nothing less
from Tkinter import *
import re
class HoverInfo(Menu):
def __init__(self, parent, text, command=None):
self._com = command
Menu.__init__(self,parent, tearoff=0)
if not isinstance(text, str):
raise TypeError('Trying to initialise a Hover Menu with a non string type: ' + text.__class__.__name__)
toktext=re.split('\n', text)
for t in toktext:
self.add_command(label = t)
self._displayed=False
self.master.bind("<Enter>",self.Display )
self.master.bind("<Leave>",self.Remove )
def __del__(self):
self.master.unbind("<Enter>")
self.master.unbind("<Leave>")
def Display(self,event):
if not self._displayed:
self._displayed=True
self.post(event.x_root, event.y_root)
if self._com != None:
self.master.unbind_all("<Return>")
self.master.bind_all("<Return>", self.Click)
def Remove(self, event):
if self._displayed:
self._displayed=False
self.unpost()
if self._com != None:
self.unbind_all("<Return>")
def Click(self, event):
self._com()
Example app using HoverInfo:
from Tkinter import *
from HoverInfo import HoverInfo
class MyApp(Frame):
def __init__(self, parent=None):
Frame.__init__(self, parent)
self.grid()
self.lbl = Label(self, text='testing')
self.lbl.grid()
self.hover = HoverInfo(self, 'while hovering press return \n for an exciting msg', self.HelloWorld)
def HelloWorld(self):
print('Hello World')
app = MyApp()
app.master.title('test')
app.mainloop()
Screenshot:

I have a very hacky solution but it has some advantages over the current answers so I figured I would share it.
lab=Label(root,text="hover me")
lab.bind("<Enter>",popup)
def do_popup(event):
# display the popup menu
root.after(1000, self.check)
popup = Menu(root, tearoff=0)
popup.add_command(label="Next")
popup.tk_popup(event.x_root, event.y_root, 0)
def check(event=None):
x, y = root.winfo_pointerxy()
widget = root.winfo_containing(x, y)
if widget is None:
root.after(100, root.check)
else:
leave()
def leave():
popup.delete(0, END)
The only real issue with this is it leaves behind a small box that moves focus away from the main window
If anyone knows how to solve these issues let me know

If anyone is on Mac OSX and tool tip isn't working, check out the example in:
https://github.com/python/cpython/blob/master/Lib/idlelib/tooltip.py
Basically, the two lines that made it work for me on Mac OSX were:
tw.update_idletasks() # Needed on MacOS -- see #34275.
tw.lift() # work around bug in Tk 8.5.18+ (issue #24570)

Here is a simple solution to your problem that subclasses the tk.Button object. We make a special class that tk.Button inherits from, giving it tooltip functionality. The same for tk.Labels.
I don't know what would be cleanest and the easiest way to maintain code for keeping track of the text that goes into the tooltips. I present here one way, in which I pass unique widget IDs to MyButtons, and access a dictionary for storing the tooltip texts. You could store this file as a JSON, or as a class attribute, or as a global variable (as below). Alternatively, perhaps it would be better to define a setter method in MyButton, and just call this method every time you create a new widget that should have a tooltip. Although you would have to store the widget instance in a variable, adding one extra line for all widgets to include.
One drawback in the code below is that the self.master.master syntax relies on determining the "widget depth". A simple recursive function will catch most cases (only needed for entering a widget, since by definition you leave somewhere you once were).
Anyway, below is a working MWE for anyone interested.
import tkinter as tk
tooltips = {
'button_hello': 'Print a greeting message',
'button_quit': 'Quit the program',
'button_insult': 'Print an insult',
'idle': 'Hover over button for help',
'error': 'Widget ID not valid'
}
class ToolTipFunctionality:
def __init__(self, wid):
self.wid = wid
self.widet_depth = 1
self.widget_search_depth = 10
self.bind('<Enter>', lambda event, i=1: self.on_enter(event, i))
self.bind('<Leave>', lambda event: self.on_leave(event))
def on_enter(self, event, i):
if i > self.widget_search_depth:
return
try:
cmd = f'self{".master"*i}.show_tooltip(self.wid)'
eval(cmd)
self.widget_depth = i
except AttributeError:
return self.on_enter(event, i+1)
def on_leave(self, event):
cmd = f'self{".master" * self.widget_depth}.hide_tooltip()'
eval(cmd)
class MyButton(tk.Button, ToolTipFunctionality):
def __init__(self, parent, wid, **kwargs):
tk.Button.__init__(self, parent, **kwargs)
ToolTipFunctionality.__init__(self, wid)
class MyLabel(tk.Label, ToolTipFunctionality):
def __init__(self, parent, wid, **kwargs):
tk.Label.__init__(self, parent, **kwargs)
ToolTipFunctionality.__init__(self, wid)
class Application(tk.Tk):
def __init__(self):
tk.Tk.__init__(self)
self.tooltip = tk.StringVar()
self.tooltip.set(tooltips['idle'])
self.frame = tk.Frame(self, width=50)
self.frame.pack(expand=True)
MyLabel(self.frame, '', text='One Cool Program').pack()
self.subframe = tk.Frame(self.frame, width=40)
self.subframe.pack()
MyButton(self.subframe, 'button_hello', text='Hello!', command=self.greet, width=20).pack()
MyButton(self.subframe, 'button_insutl', text='Insult', command=self.insult, width=20).pack()
MyButton(self.subframe, 'button_quit', text='Quit', command=self.destroy, width=20).pack()
tk.Label(self.subframe, textvar=self.tooltip, width=20).pack()
def show_tooltip(self, wid):
try:
self.tooltip.set(tooltips[wid])
except KeyError:
self.tooltip.set(tooltips['error'])
def hide_tooltip(self):
self.tooltip.set(tooltips['idle'])
def greet(self):
print('Welcome, Fine Sir!')
def insult(self):
print('You must be dead from the neck up')
if __name__ == '__main__':
app = Application()
app.mainloop()

The best way I have found to create a popup help window is to use the tix.Balloon. I have modified it below to make it look better and show an example (note the use of tix.Tk):
import tkinter as tk
import tkinter.tix as tix
class Balloon(tix.Balloon):
# A modified tix popup balloon (to change the default delay, bg and wraplength)
init_after = 1250 # Milliseconds
wraplength = 300 # Pixels
def __init__(self, master):
bg = root.cget("bg")
# Call the parent
super().__init__(master, initwait=self.init_after)
# Change background colour
for i in self.subwidgets_all():
i.config(bg=bg)
# Modify the balloon label
self.message.config(wraplength=self.wraplength)
root = tix.Tk()
l = tk.Label(root, text="\n".join(["text"] * 5))
l.pack()
b = Balloon(root.winfo_toplevel())
b.bind_widget(l, balloonmsg="Some random text")
root.mainloop()
OLD ANSWER:
Here is an example using <enter> and <leave> as #bryanoakley suggested with a toplevel (with overridedirect set to true). Use the hover_timer class for easy use of this. This needs the widget and help-text (with an optional delay argument - default 0.5s) and can be easily called just by initiating the class and then cancelling it.
import threading, time
from tkinter import *
class hover_window (Toplevel):
def __init__ (self, coords, text):
super ().__init__ ()
self.geometry ("+%d+%d" % (coords [0], coords [1]))
self.config (bg = "white")
Label (self, text = text, bg = "white", relief = "ridge", borderwidth = 3, wraplength = 400, justify = "left").grid ()
self.overrideredirect (True)
self.update ()
self.bind ("<Enter>", lambda event: self.destroy ())
class hover_timer:
def __init__ (self, widget, text, delay = 2):
self.wind, self.cancel_var, self.widget, self.text, self.active, self.delay = None, False, widget, text, False, delay
threading.Thread (target = self.start_timer).start ()
def start_timer (self):
self.active = True
time.sleep (self.delay)
if not self.cancel_var: self.wind = hover_window ((self.widget.winfo_rootx (), self.widget.winfo_rooty () + self.widget.winfo_height () + 20), self.text)
self.active = False
def delayed_stop (self):
while self.active: time.sleep (0.05)
if self.wind:
self.wind.destroy ()
self.wind = None
def cancel (self):
self.cancel_var = True
if not self.wind: threading.Thread (target = self.delayed_stop).start ()
else:
self.wind.destroy ()
self.wind = None
def start_help (event):
# Create a new help timer
global h
h = hover_timer (l, "This is some additional information.", 0.5)
def end_help (event):
# If therre is one, end the help timer
if h: h.cancel ()
if __name__ == "__main__":
# Create the tkinter window
root = Tk ()
root.title ("Hover example")
# Help class not created yet
h = None
# Padding round label
Frame (root, width = 50).grid (row = 1, column = 0)
Frame (root, height = 50).grid (row = 0, column = 1)
Frame (root, width = 50).grid (row = 1, column = 2)
Frame (root, height = 50).grid (row = 2, column = 1)
# Setup the label
l = Label (root, text = "Hover over me for information.", font = ("sans", 32))
l.grid (row = 1, column = 1)
l.bind ("<Enter>", start_help)
l.bind ("<Leave>", end_help)
# Tkinter mainloop
root.mainloop ()

I wanted to contribute to the answer of #squareRoot17 as he inspired me to shorten his code while providing the same functionality:
import tkinter as tk
class ToolTip(object):
def __init__(self, widget, text):
self.widget = widget
self.text = text
def enter(event):
self.showTooltip()
def leave(event):
self.hideTooltip()
widget.bind('<Enter>', enter)
widget.bind('<Leave>', leave)
def showTooltip(self):
self.tooltipwindow = tw = tk.Toplevel(self.widget)
tw.wm_overrideredirect(1) # window without border and no normal means of closing
tw.wm_geometry("+{}+{}".format(self.widget.winfo_rootx(), self.widget.winfo_rooty()))
label = tk.Label(tw, text = self.text, background = "#ffffe0", relief = 'solid', borderwidth = 1).pack()
def hideTooltip(self):
tw = self.tooltipwindow
tw.destroy()
self.tooltipwindow = None
This class can then be imported and used as:
import tkinter as tk
from tooltip import ToolTip
root = tk.Tk()
your_widget = tk.Button(root, text = "Hover me!")
ToolTip(widget = your_widget, text = "Hover text!")
root.mainloop()

tkinter app adding a right click context menu?

I have a python-tkinter gui app that I've been trying to find some way to add in some functionality. I was hoping there would be a way to right-click on an item in the app's listbox area and bring up a context menu. Is tkinter able to accomplish this? Would I be better off looking into gtk or some other gui-toolkit?

You would create a Menu instance and write a function that calls
its post() or tk_popup() method.
The tkinter documentation doesn't currently have any information about tk_popup().
Read the Tk documentation for a description, or the source:
library/menu.tcl in the Tcl/Tk source:
::tk_popup --
This procedure pops up a menu and sets things up for traversing
the menu and its submenus.
Arguments:
menu - Name of the menu to be popped up.
x, y - Root coordinates at which to pop up the menu.
entry - Index of a menu entry to center over (x,y).
If omitted or specified as {}, then menu's
upper-left corner goes at (x,y).
tkinter/__init__.py in the Python source:
def tk_popup(self, x, y, entry=""):
"""Post the menu at position X,Y with entry ENTRY."""
self.tk.call('tk_popup', self._w, x, y, entry)
You associate your context menu invoking function with right-click via:
the_widget_clicked_on.bind("<Button-3>", your_function).
However, the number associated with right-click is not the same on every platform.
library/tk.tcl in the Tcl/Tk source:
On Darwin/Aqua, buttons from left to right are 1,3,2.
On Darwin/X11 with recent XQuartz as the X server, they are 1,2,3;
other X servers may differ.
Here is an example I wrote that adds a context menu to a Listbox:
import tkinter # Tkinter -> tkinter in Python 3
class FancyListbox(tkinter.Listbox):
def __init__(self, parent, *args, **kwargs):
tkinter.Listbox.__init__(self, parent, *args, **kwargs)
self.popup_menu = tkinter.Menu(self, tearoff=0)
self.popup_menu.add_command(label="Delete",
command=self.delete_selected)
self.popup_menu.add_command(label="Select All",
command=self.select_all)
self.bind("<Button-3>", self.popup) # Button-2 on Aqua
def popup(self, event):
try:
self.popup_menu.tk_popup(event.x_root, event.y_root, 0)
finally:
self.popup_menu.grab_release()
def delete_selected(self):
for i in self.curselection()[::-1]:
self.delete(i)
def select_all(self):
self.selection_set(0, 'end')
root = tkinter.Tk()
flb = FancyListbox(root, selectmode='multiple')
for n in range(10):
flb.insert('end', n)
flb.pack()
root.mainloop()
The use of grab_release() was observed in an example on effbot.
Its effect might not be the same on all systems.

I made some changes to the conext menu code above in order to adjust my demand and I think it would be useful to share:
Version 1:
import tkinter as tk
from tkinter import ttk
class Main(tk.Frame):
def __init__(self, master):
tk.Frame.__init__(self, master)
master.geometry('500x350')
self.master = master
self.tree = ttk.Treeview(self.master, height=15)
self.tree.pack(fill='x')
self.btn = tk.Button(master, text='click', command=self.clickbtn)
self.btn.pack()
self.aMenu = tk.Menu(master, tearoff=0)
self.aMenu.add_command(label='Delete', command=self.delete)
self.aMenu.add_command(label='Say Hello', command=self.hello)
self.num = 0
# attach popup to treeview widget
self.tree.bind("<Button-3>", self.popup)
def clickbtn(self):
text = 'Hello ' + str(self.num)
self.tree.insert('', 'end', text=text)
self.num += 1
def delete(self):
print(self.tree.focus())
if self.iid:
self.tree.delete(self.iid)
def hello(self):
print ('hello!')
def popup(self, event):
self.iid = self.tree.identify_row(event.y)
if self.iid:
# mouse pointer over item
self.tree.selection_set(self.iid)
self.aMenu.post(event.x_root, event.y_root)
else:
pass
root = tk.Tk()
app=Main(root)
root.mainloop()
Version 2:
import tkinter as tk
from tkinter import ttk
class Main(tk.Frame):
def __init__(self, master):
master.geometry('500x350')
self.master = master
tk.Frame.__init__(self, master)
self.tree = ttk.Treeview(self.master, height=15)
self.tree.pack(fill='x')
self.btn = tk.Button(master, text='click', command=self.clickbtn)
self.btn.pack()
self.rclick = RightClick(self.master)
self.num = 0
# attach popup to treeview widget
self.tree.bind('<Button-3>', self.rclick.popup)
def clickbtn(self):
text = 'Hello ' + str(self.num)
self.tree.insert('', 'end', text=text)
self.num += 1
class RightClick:
def __init__(self, master):
# create a popup menu
self.aMenu = tk.Menu(master, tearoff=0)
self.aMenu.add_command(label='Delete', command=self.delete)
self.aMenu.add_command(label='Say Hello', command=self.hello)
self.tree_item = ''
def delete(self):
if self.tree_item:
app.tree.delete(self.tree_item)
def hello(self):
print ('hello!')
def popup(self, event):
self.aMenu.post(event.x_root, event.y_root)
self.tree_item = app.tree.focus()
root = tk.Tk()
app=Main(root)
root.mainloop()

from tkinter import *
root=Tk()
root.geometry("500x400+200+100")
class Menu_Entry(Entry):
def __init__(self,perant,*args,**kwargs):
Entry.__init__(self,perant,*args,**kwargs)
self.popup_menu=Menu(self,tearoff=0,background='#1c1b1a',fg='white',
activebackground='#534c5c',
activeforeground='Yellow')
self.popup_menu.add_command(label="Cut ",command=self.Cut,
accelerator='Ctrl+V')
self.popup_menu.add_command(label="Copy ",command=self.Copy,compound=LEFT,
accelerator='Ctrl+C')
self.popup_menu.add_command(label="Paste ",command=self.Paste,accelerator='Ctrl+V')
self.popup_menu.add_separator()
self.popup_menu.add_command(label="Select all",command=self.select_all,accelerator="Ctrl+A")
self.popup_menu.add_command(label="Delete",command=self.delete_only,accelerator=" Delete")
self.popup_menu.add_command(label="Delete all",command=self.delete_selected,accelerator="Ctrl+D")
self.bind('<Button-3>',self.popup)
self.bind("<Control-d>",self.delete_selected_with_e1)
self.bind('<App>',self.popup)
self.context_menu = Menu(self, tearoff=0)
self.context_menu.add_command(label="Cut")
self.context_menu.add_command(label="Copy")
self.context_menu.add_command(label="Paste")
def popup(self, event):
try:
self.popup_menu.tk_popup(event.x_root, event.y_root, 0)
finally:
self.popup_menu.grab_release()
def Copy(self):
self.event_generate('<<Copy>>')
def Paste(self):
self.event_generate('<<Paste>>')
def Cut(self):
self.event_generate('<<Cut>>')
def delete_selected_with_e1(self,event):
self.select_range(0, END)
self.focus()
self.event_generate("<Delete>")
def delete_selected(self):
self.select_range(0, END)
self.focus()
self.event_generate("<Delete>")
def delete_only(self):
self.event_generate("<BackSpace>")
def select_all(self):
self.select_range(0, END)
self.focus()
ent=Menu_Entry(root)
ent.pack()
root.mainloop()

Important Caveat:
(Assuming the event argument that contains the coordinates is called "event"): Nothing will happen or be visible when you call tk_popup(...) unless you use "event.x_root" and "event.y_root" as arguments. If you do the obvious of using "event.x" and "event.y", it won't work, even though the names of the coordinates are "x" and "y" and there is no mention of "x_root" and "y_root" anywhere within it.
As for the grab_release(..), it's not necessary, anywhere. "tearoff=0" also isn't necessary, setting it to 1 (which is default), simply adds a dotted line entry to the context menu. If you click on it, it detaches the context menu and makes it its own top-level window with window decorators. tearoff=0 will hide this entry. Moreover, it doesn't matter if you set the menu's master to any specific widget or root, or anything at all.