Develop Reference

communication between tkinter toplevels

I'm working on a little project and made a little on-screen keyboard as a tkinter Toplevel
my application is buildt like this:
Root-Window (Tk-Widget)
input 1 (Entry-Widget)
input 2 (Entry-Widget)
input 3 (Text-Widget)
on_screen-keyboard (Toplevel-Widget)
the Toplevel-Widget contains Buttons, with callbacks that should enter text in the entries (just like keyboard-Buttons)
What I want is a communication between children of the keyboard/the keyboard and the last active input-Widget. My Problem is, that I don't know, how to say the keyboard, to which input-Widget it should send the message.
import tkinter as tk
from tkinter import ttk
class MainWindow(tk.Tk):
def __init__(self, *args, **kwargs):
tk.Tk.__init__(self, *args, **kwargs)
self.active_input = tk.Variable(value=None)
ttk.Button(self, text="show Keyboard", command=lambda: Keyboard(self)).pack()
self.text = tk.StringVar(value="")
self.input1 = ttk.Entry(self)
self.input1.bind("<FocusIn>", lambda e: self.active_input.set(self.input1))
self.input2 = ttk.Entry(self)
self.input2.bind("<FocusIn>", lambda e: self.active_input.set(self.input2))
self.input3 = tk.Text(self, height=3, width=15)
self.input3.bind("<FocusIn>", lambda e: self.active_input.set(self.input3))
self.input1.pack()
self.input3.pack()
self.input2.pack()
class Keyboard(tk.Toplevel):
OPENED = False
NAME = "- Keyboard -"
NUM = [{"text":"1", "width":1},
{"text":"2", "width":1},
{"text":"3", "width":2}]
CHAR= [{"text":"A", "width":1},
{"text":"B", "width":1},
{"text":"C", "width":2}]
def __init__(self, master):
if not Keyboard.OPENED:
Keyboard.OPENED = True
print("keyboard opened!")
self.master = master
tk.Toplevel.__init__(self, master)
self.title(self.NAME)
self.protocol("WM_DELETE_WINDOW", self.close)
self.keyb_nb = ttk.Notebook(self)
self.keyb_nb.pack()
self.num_tab = ttk.Frame(self.keyb_nb)
self.createPad(self.num_tab, Keyboard.NUM,2)
self.keyb_nb.add(self.num_tab, text="123")
self.char_tab = ttk.Frame(self.keyb_nb)
self.createPad(self.char_tab, Keyboard.CHAR, 2)
self.keyb_nb.add(self.char_tab, text="ABC")
def createPad(self, master, pad:list, max_col):
self.co_count = 0
self.ro = 1
for button in pad:
button["id"] = ttk.Button(master, width=6*button["width"], text=button["text"], command=self.bclicked(button))
if self.co_count >= max_col:
self.ro = self.ro + 1
self.co_count = 0
button["id"].grid(row=self.ro, columnspan=button["width"], column=self.co_count)
self.co_count = self.co_count+button["width"]
def bclicked(self, button:dict):
"""
reciver = self.master.active_input #I think the Problem here is, that the variable contains a string, not a widget
reciever.focus_force()
reciever.insert(index=tk.INSERT, string=button["text"])
"""
pass
def close(self):
Keyboard.OPENED = False
self.destroy()
print("keyboard closed!")
root = MainWindow()
root.mainloop()
Here the init of the Mainwindow and the bclicked of the Keyboard class are important...
the code is debug-ready
I would prefer a solution, similar to the communication in the internet (sender=button, receiver-id, message), but very welcome every working solution
btw: I'm also looking for a solution, how I don't have to force the input to focus and the Toplevel stays an the highest layer of the screen (that if I focus the Tk-Widget/one of the inputs/the button, the keyboard will stay in front of it)
SUMMARY: how do I find out, which of the 3 input-widgets was active at last, when the keyboard-toplevel has already the focus?

I may made more changes than needed, but mainly focus on the method keyboard_triger() and pass_key_to_master(), this two use the idea that the variable master implements, having access to call methods out of scope.
Olso the method set_focused_object() stores a reference to the last object beeng focused, note than it stores the widget and not the event, it's easyer than searching each time the object
import tkinter as tk
from tkinter import ttk
class MainWindow(tk.Tk):
def keyboard_triger(self, key):
# to identify wath object is just use
# isinstance(self.active_input, ttk.Entry)
self.active_input.insert(tk.END, key)
def new_keyboard(self):
Keyboard(self)
def set_focused_object(self, event):
self.active_input = event.widget
def __init__(self):
tk.Tk.__init__(self)
self.active_input = None
ttk.Button(self, text="Show Keyboard", command=self.new_keyboard).pack()
self.input1 = ttk.Entry(self)
self.input1.bind("<FocusIn>", self.set_focused_object)
self.input1.pack()
self.input2 = ttk.Entry(self)
self.input2.bind("<FocusIn>", self.set_focused_object)
self.input2.pack()
self.input3 = tk.Text(self, height=3, width=15)
self.input3.bind("<FocusIn>", self.set_focused_object)
self.input3.pack()
class Keyboard(tk.Toplevel):
def pass_key_to_master(self, key):
self.master.keyboard_triger(key)
def __init__(self, master):
tk.Toplevel.__init__(self, master)
self.master = master
self.title('Keyboard')
# this way of agruping keys stores the kwags
# of the drawing method
keys = {
'A': {'x': 0, 'y': 0},
'B': {'x': 20, 'y': 20},
'C': {'x': 50, 'y': 50}
}
# expected structure
# {string key: reference to the button}
self.buttons = {}
for i in keys:
self.buttons[i] = tk.Button( # i=i is required to make a instance
self, text=i, command=lambda i=i: self.pass_key_to_master(i)
)
self.buttons[i].place(**keys[i])
if __name__ == '__main__':
root = MainWindow()
root.mainloop()

Your code maybe could have a better construction.(But I didn't revise your code construction.)
Followed by your code,I use a global variable.And fix some errors in your code.And it could work normally in my computer.
import tkinter as tk
from tkinter import ttk
class MainWindow(tk.Tk):
def __init__(self, *args, **kwargs):
tk.Tk.__init__(self, *args, **kwargs)
self.active_input = tk.Variable(value=None)
ttk.Button(self, text="show Keyboard", command=lambda: Keyboard(self)).pack()
global focusedWidget
focusedWidget = None
self.text = tk.StringVar(value="")
self.input1 = ttk.Entry(self)
self.input1.bind("<FocusIn>", self.getFocusWidget)
self.input2 = ttk.Entry(self)
self.input2.bind("<FocusIn>", self.getFocusWidget)
self.input3 = tk.Text(self, height=3, width=15)
self.input3.bind("<FocusIn>", self.getFocusWidget)
self.input1.pack()
self.input3.pack()
self.input2.pack()
def getFocusWidget(self,event): # this function could be a static function
global focusedWidget
focusedWidget = event.widget
class Keyboard(tk.Toplevel):
OPENED = False
NAME = "- Keyboard -"
NUM = [{"text":"1", "width":1},
{"text":"2", "width":1},
{"text":"3", "width":2}]
CHAR= [{"text":"A", "width":1},
{"text":"B", "width":1},
{"text":"C", "width":2}]
def __init__(self, master):
if not Keyboard.OPENED:
Keyboard.OPENED = True
print("keyboard opened!")
self.master = master
tk.Toplevel.__init__(self, master)
self.title(self.NAME)
self.protocol("WM_DELETE_WINDOW", self.close)
self.keyb_nb = ttk.Notebook(self)
self.keyb_nb.pack()
self.num_tab = ttk.Frame(self.keyb_nb)
self.createPad(self.num_tab, Keyboard.NUM,2)
self.keyb_nb.add(self.num_tab, text="123")
self.char_tab = ttk.Frame(self.keyb_nb)
self.createPad(self.char_tab, Keyboard.CHAR, 2)
self.keyb_nb.add(self.char_tab, text="ABC")
def createPad(self, master, pad:list, max_col):
self.co_count = 0
self.ro = 1
for button in pad:
button["id"] = ttk.Button(master, width=6*button["width"], text=button["text"], command=lambda button=button:self.bclicked(button)) # this lambda expression has some errors.
if self.co_count >= max_col:
self.ro = self.ro + 1
self.co_count = 0
button["id"].grid(row=self.ro, columnspan=button["width"], column=self.co_count)
self.co_count = self.co_count+button["width"]
def bclicked(self, button:dict):
global focusedWidget
"""
reciver = self.master.active_input #I think the Problem here is, that the variable contains a string, not a widget
reciever.focus_force()
reciever.insert(index=tk.INSERT, string=button["text"])
"""
if not focusedWidget: # If user hasn't click a entry or text widget.
print("Please select a entry or text")
return
if focusedWidget.widgetName=='ttk::entry': # use if statement to check the type of selected entry.
focusedWidget.insert(index=tk.INSERT,string=button["text"])
else:
focusedWidget.insert("end",button["text"])
def close(self):
Keyboard.OPENED = False
self.destroy()
print("keyboard closed!")
root = MainWindow()
root.mainloop()

Python tkinter threading and window refresh

I'm using python and tkinter to build a visualization tool that can refresh and visualize an updating object. Right now, the object can't change because the threading is not working. Any help or general knowledge would be appreciated. I'm relatively new to threading and tkinter.
example object I want to ingest
class color1:
def __init__(self, color):
self.color = color
def change_col(self, new_color):
self.color = new_color
def pass_col(self):
return(self)
my visualization code
class my_visual(threading.Thread):
def __init__(self, col1):
threading.Thread.__init__(self)
self.start()
self.col1 = col1
def viz(self):
self.root = Tk()
btn1 = Button(self.root, text = 'Refresh', command = self.refresh)
btn1.pack()
frame = Frame(self.root, width = 100, height = 100, bg = self.col1.color)
frame.pack()
btn2 = Button(self.root, text = 'Close', command = self.exit)
btn2.pack()
self.root.mainloop()
def refresh(self):
self.root.quit()
self.root.destroy()
self.col1 = self.col1.pass_col()
self.viz()
def exit(self):
self.root.quit()
self.root.destroy()
Code that works
c = color1('RED')
test = my_visual(c)
test.viz()
Code that doesn't work
In this version, the refresh works, but the threading doesn't. When the threading is working, the refresh won't pick up that the object has changed.
c.change_col('BLUE')

If you extend the threading.Thread class you need to override the run() method with your custom functionality. With no run method, the thread dies immediately. You can test whether a thread is alive with my_visual.is_alive().

The problem is that your test.viz() is an infinite loop because of self.root.mainloop(), so you cannot do anything once you called that function. The solution is to use a thread for test.viz(), and your thread for the class my_visual is no more necessary.
I added a time.sleep of 2 seconds before the refresh makes it blue, otherwise the color is blue at beginning.
Here you go :
import threading
from tkinter import *
import time
class color1:
def __init__(self, color):
self.color = color
def change_col(self, new_color):
self.color = new_color
def pass_col(self):
return(self)
class my_visual():
def __init__(self, col1):
self.col1 = col1
def viz(self):
self.root = Tk()
btn1 = Button(self.root, text = 'Refresh', command = self.refresh)
btn1.pack()
frame = Frame(self.root, width = 100, height = 100, bg = self.col1.color)
frame.pack()
btn2 = Button(self.root, text = 'Close', command = self.exit)
btn2.pack()
self.root.mainloop()
def refresh(self):
self.root.quit()
self.root.destroy()
self.col1 = self.col1.pass_col()
print("self.col1", self.col1, self.col1.color)
self.viz()
def exit(self):
self.root.quit()
self.root.destroy()
c = color1('RED')
test = my_visual(c)
t2 = threading.Thread(target = test.viz)
t2.start()
time.sleep(2)
print('Now you can change to blue when refreshing')
c.change_col('BLUE')

Display log lines on screen using parallel GUI

I'm looking for elegant way to display log lines on screen while the script is running.
from time import sleep
from threading import Thread
import tkinter as tk
class WaitGuiPrallel(Thread):
def __init__(self, TXT='Wait!', ttl='Logs'):
self.txt = TXT
Thread.__init__(self)
self.ttl = ttl
self.start() # This is starting the self.run()
def run(self):
self.root = tk.Tk()
self.root.attributes("-topmost", True)
self.root.title(self.ttl)
self.label = tk.Label(self.root, text=self.txt, font=("Helvetica", 20))
self.label.pack()
self.Location()
self.root.mainloop()
def Exit(self):
self.root.quit()
def Location(self):
w = 500 # width for the Tk root
h = 150 # height for the Tk root
ws = self.root.winfo_screenwidth() # width of the screen
self.root.geometry('%dx%d+%d+%d' % (w, h, ws - w - 20, 10))
def Update(self, newText):
self.txt1 = newText
self.label.destroy()
self.label = tk.Label(self.root, text=self.txt1,
font=("Helvetica", 12))
self.label.pack()
self.root.update()
Wait = WaitGuiPrallel(TXT='Wait! Do not touch mouse or keyboard')
sleep(2)
for t in range(5):
sleep(1)
Wait.Update(newText='Log line %s' % t)
Wait.Update(newText='Done!')
sleep(1)
Wait.Exit()
The current script got few issues:
it is not elegant - there must be a better way
it has problems when updated from different Threads
Sometime running it twice from Spyder+IPython is not possible (IPython freeze)

Tkinter doesn't really play well with threads. Using a StringVar is a little more thread friendly than other methods (in my experience). Here's how to do that plus a couple other fixes:
from time import sleep
from threading import Thread
import tkinter as tk
class WaitGuiPrallel(Thread):
def __init__(self, TXT='Wait!', ttl='Logs'):
Thread.__init__(self)
self.txt = TXT
self.ttl = ttl # what's this for?
self.daemon = True # this thread will terminate when the main thread terminates
self.start() # This is starting the self.run()
def run(self):
self.root = tk.Tk()
self.root.attributes("-topmost", True)
self.root.title(self.ttl)
self.txt = tk.StringVar(value=self.txt)
self.label = tk.Label(self.root, textvariable=self.txt, font=("Helvetica", 20))
self.label.pack()
self.Location()
self.root.mainloop()
def Location(self):
w = 500 # width for the Tk root
h = 150 # height for the Tk root
ws = self.root.winfo_screenwidth() # width of the screen
self.root.geometry('%dx%d+%d+%d' % (w, h, ws - w - 20, 10))
Wait = WaitGuiPrallel(TXT='Wait! Do not touch mouse or keyboard')
sleep(2)
for t in range(5):
sleep(1)
Wait.txt.set('Log line %s' % t)
Wait.txt.set('Done!')
sleep(1)
If you have multiple threads calling this then I would consider using a Queue and a third thread to monitor the queue.

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 Freeze on grid_remove

So I am trying to build a GUI where I enter some information, clear the entry fields, and then add new entry fields. However, when I try to clear the frame from the root via grid_remove, the application freezes. The relevant code is below.
import tkinter
from threading import Thread
class PinGui(tkinter.Frame):
def __init__(self, client):
self.client = client
self.root = client.root
self.add_pin = client.add_pin
self.end = client.end
tkinter.Frame.__init__(self, self.root)
self.grid_widgets()
self.grid_buttons()
self.bind_keys()
self.grid(padx=32, pady=32)
def grid_buttons(self, b1='Add', b2='Reset', b3='Quit'):
self.addButton = tkinter.Button(self, text=b1, command=self.validate)
self.resetButton = tkinter.Button(self, text=b2, command=self.reset)
self.quitButton = tkinter.Button(self, text=b3, command=self.end)
self.buttons = [self.addButton, self.resetButton, self.quitButton]
for i in range(3): self.buttons[i].grid(row=i, column=11)
def grid_widgets(self):
widths = [3,3,4,4,6]
self.pin_vars = []
self.pin_fields = []
for i in range(5):
self.pin_vars.append(tkinter.StringVar())
self.pin_fields.append(
tkinter.Entry(self,width=widths[i], textvariable=self.pin_vars[i])
)
self.pin_fields[i].grid(row=0, column=2*i, padx=3)
self.pin_fields[0].focus_set()
def bind_keys(self):
self.root.bind_all("<Return>", self.validate)
self.root.bind_all("<Escape>", self.end)
def validate(self, args=None):
self.client.pin = []
for field in self.pin_fields:
self.client.pin.append(field.get())
Thread(target=self.add_pin).start()
def ungrid(self):
for field in self.pin_fields: field.grid_remove()
for button in self.buttons: button.grid_remove()
self.display.grid_remove()
And:
class PinClient:
def __init__(self):
self.root = tkinter.Tk()
self.gui = PinGui(self)
self.pins = []
def add_pin(self):
self.gui.reset()
if 'display' in self.__dict__:
self.pins.append(self.pin)
self.display.add_pin(self.pin)
self.ping("Enter PIN for Comp %s:" % len(self.display.col1))
if len(self.display.col1) > 5:
self.end() # THIS IS WHERE IT FREEZES
else:
self.subject = self.pin
self.display = Display(self.root, self.pin)
self.display.grid(row=1, padx=32, pady=32)
self.ping("Enter PIN for Comp 1:")
def ping(self, msg):
self.gui.d_var.set(msg)
def end(self, args=None):
self.gui.ungrid()
class Display(tkinter.Frame):
def __init__(self, master, pin):
tkinter.Frame.__init__(self, master)
self.pin = pin
self.col1 = []
self.col2 = []
self.col1.append(tkinter.Label(self, text="Subject:"))
self.col2.append(tkinter.Label(self, text=self.pin))
self.grid_widgets()
def grid_widgets(self):
self.ungrid()
for i in range(len(self.col1)):
self.col1[i].grid(row=i, column=0)
self.col2[i].grid(row=i, column=1)
def ungrid(self):
for i in range(len(self.col1)):
self.col1[i].grid_remove()
self.col2[i].grid_remove()
def add_pin(self, pin):
self.col1.append(tkinter.Label(self, text="Comp %s:" % len(self.col1)))
self.col2.append(tkinter.Label(self, text=pin))
i = len(self.col1)
self.col1[i-1].grid(row=i, column=0)
self.col2[i-1].grid(row=i, column=1)
It seems to be somehow related to the threading, but I haven't been able to find any reason this should freeze. Any help is greatly appreciated!

Tkinter is not thread safe. If you do anything in a thread other than the main thread that touches a GUI object then you will get unpredictable results. Almost certainly, it is threading that is causing your problem, since you are trying to access widgets from the worker thread.