I've seen some usage of self.destroy() within classes but I couldn't get it working with what I wanted it to do.
I have the class resultsPage that shows results obtained on another page. I have made the displayResults(pageNo) function to show these when resultsPage is visible. The problem arises with the back and next buttons which are made to go between pages of results. All widgets are created on top of each other but I want to remove them all then create the new ones. I added self.destroy() to try and fix this but it didn't work.
I'm not sure if it's to do with the placement of where I'm defining my functions but I have had a play around with where they're defined and it hasn't changed the error message.
This is a simplified example of my code:
class resultsPage(tk.Frame):
def __init__(self, parent, controller):
tk.Frame.__init__(self, parent)
def onShowFrame(self, event):
def displayResults(pageNo):
self.destroy()
#Create widgets related to pageNo
#Create back and next buttons e.g.
back = tk.Button(self, text="<=",
command=lambda: displayResults(pageNo - 1))
displayResults(1)
The error I get is: _tkinter.TclError: bad window path name ".!frame.!previewresultspage"
If it helps, I can post my full code but I thought I'd generalise it so it's more helpful to others.
You are deleting the widget in onShowFrame, and then immediately try to create a new widget with it as the parent. You can't use a deleted widget as the parent of another widget.
As pointed out, using self.destroy() in this case, will not work. To achieve the goal of deleting all widgets on the frame, you can use a loop (credit to #stovfl):
for widget in self.grid_slaves():
widget.destroy()
Related
I am creating a Tkinter/Python3 application where the main window inherits from Notebook (i need tabs), and each tab should be a custom class inheriting from Frame (I would then dynamically use matplotlib to create custom graphs).
Unfortunately I don't seem to be able to have Notebook accept my custom Frames.
Following very reduced snippet of code:
#!/usr/bin/env python3
from tkinter import *
from tkinter.ttk import Notebook
class MyFrame1(Frame):
def __init__(self, master=None, mytext=""):
super().__init__(master)
self.create_widgets(mytext)
def create_widgets(self, mytext):
self.label = Label(self.master, text=mytext, anchor=W)
# this is not placed relative to the Frame, but to the
# master
# 1. How I get the relative coordinates inside the frame
# to be 10, 10 of the frame area?
self.label.place(x=10, y=10, width=128, height=24)
class MyNotebook(Notebook):
def __init__(self, master=None):
super().__init__(master)
self.create_widgets()
def create_widgets(self):
self.f1 = MyFrame1(self, "abc")
# once the UI is drawn, the label "def" seems to overlay
# "abc" even when "f1" is selected
# 2. Why is self.f2 always shown even when self.f1 is
# selected?
self.f2 = MyFrame1(self, "def")
self.add(self.f1, text="f1")
self.add(self.f2, text="f2")
# Without this command nothing gets drawn
# 3. Why is this? Is this equivalent of 'pack' but for
# pixel driven layout?
self.place(width=640, height=480)
def main():
root = Tk()
root.minsize(640, 480)
root.geometry("640x480")
app = MyNotebook(master=root)
# this works as intended the label is indeed placed
# in the frame at 10, 10
#app = MyFrame1(master=root, mytext="123abc")
app.mainloop()
return None
if __name__ == "__main__":
main()
As per comments I have the following main question: why aren't my custom instances of MyFrame1 properly displayed inside MyNotebook?
Sub questions:
How can I get relative coordinate areas of where the frame is located when place my elements (in this case a Label)?
Why even when self.f1 tab is selected in the UI, I can still see the content of self.f2 tab?
Is self.place required in order to show all sub-elements when not using pack?
If I dynamically create Tkinter elements after the MyNotebook is initialized, will those be bound to respective tabs?
Not sure what I'm doing wrong?
Thanks!
Not sure what I'm doing wrong?
Your create_widgets method needs to add widgets to self, not self.master.
How can I get relative coordinate areas of where the frame is located when place my elements (in this case a Label)?
I don't understand what you mean by this. When you use place, coordinates will be interpreted relative to the frame. However, I strongly advise against using place. Both pack and grid will trigger the frame to resize to fit its children which almost always results in a more responsive UI
Why even when self.f1 tab is selected in the UI, I can still see the content of self.f2 tab?
Because you added internal widgets to self.master instead of self.
Is self.place required in order to show all sub-elements when not using pack?
No. It is required to use a geometry manager but it doesn't have to be place. Usually, place is the least desirable geometry manager to use. pack and grid are almost always better choices except for some very specific situations.
If I dynamically create Tkinter elements after the MyNotebook is initialized, will those be bound to respective tabs?
They will be in whatever tab you put them in.
Finally, I would suggest that you remove self.place in create_widgets. Instead, call pack, place, or grid in the same block of code that creates an instance of that class.
It's a bad practice for a widget to add itself to another widget's layout. The code that creates the widget should be the code that adds the widget to the layout.
I know similar things have been asked a lot, but I've tried to figure this out for two hours now and I'm not getting anywhere. I want to have a button in a Tkinter window that is only visible on mouseover. So far I failed at making the button invisible in the first place (I'm familiar with events and stuff, that's not what this question is about) pack_forget() won't work, because I want the widget to stay in place. I'd like some way to do it like I indicated in the code below:
import tkinter as tki
class MyApp(object):
def __init__(self, root_win):
self.root_win = root_win
self.create_widgets()
def create_widgets(self):
self.frame1 = tki.Frame(self.root_win)
self.frame1.pack()
self.btn1 = tki.Button(self.frame1, text='I\'m a button')
self.btn1.pack()
self.btn1.visible=False #This doesnt't work
def main():
root_win = tki.Tk()
my_app = MyApp(root_win)
root_win.mainloop()
if __name__ == '__main__':
main()
Is there any way to set the visibility of widgets directly? If not, what other options are there?
Use grid as geometry manager and use:
self.btn1.grid_remove()
which will remember its place.
You can try using event to call function.
If "Enter" occurs for button then call a function that calls pack()
and if "Leave" occurs for button then call a function that calls pack_forget().
Check this link for event description:List of All Tkinter Events
If you wish your button to stay at a defined place then you can use place(x,y) instead of pack()
I've been struggling with this for a while. I think I'm missing some simple piece of information and I hope you guys can help clear this up for me.
I'm trying to get tkinter to display different frames which I will eventually place widgets inside of. Here's what I did:
I've made a class that is supposed to initialize the window and make all the different frames the program will run.
I've made a separate class for each frame(I'm intending to have variables associated with the different classes when the program is done), and assigned a variable that will start that class up and make it run it's init function
I ended the StartUp class by telling it to tkraise() the frame I want displayed, and that's where things stop working correctly.
I set each frame to a different color, so when you run this program you will see that they split the screen space up instead of one being raised to the top. What am I missing?
One last point, I am purposely trying to spell everything out in my program, I learn better that way. I left it so I have to type tkinter.blah-blah-blah in front of each tkinter command so I can recognize them easily, and I decided not to have my classes inherit Frame or Tk or anything. I'm trying to understand what I'm doing.
import tkinter
class StartUp:
def __init__(self):
self.root = tkinter.Tk()
self.root.geometry('300x300')
self.container = tkinter.Frame(master=self.root, bg='blue')
self.container.pack(side='top', fill='both', expand=True)
self.page1 = Page1(self)
self.page2 = Page2(self)
self.page1.main_frame.tkraise()
class Page1():
def __init__(self, parent):
self.main_frame = tkinter.Frame(master=parent.container, bg='green')
self.main_frame.pack(side='top', fill='both', expand=True)
class Page2():
def __init__(self, parent):
self.main_frame = tkinter.Frame(master=parent.container, bg='yellow')
self.main_frame.pack(side='top', fill='both', expand=True)
boot_up = StartUp()
boot_up.root.mainloop()
When you do pack(side='top', ...), top doesn't refer to the top of the containing widget, it refers to the top of any empty space in the containing widget. Page initially takes up all of the space, and then when you pack Page2, it goes below Page1 rather than being layered on top of it.
If you are using the strategy of raising one window above another, you need to either use grid or place to layer the widgets on top of each other. The layering is something pack simply can't do.
Your other choice is to call pack_forget on the current window before calling pack on the new windowl
I am working on a program where I create some widgets in a for loop. So I need to get the name of them dynamically. I have set up is when the mouse enters the frame. Which holds the two text label widgets. I causes a function to run. And I want to change the background color of a widget with the name of noteName. But I seem to have run into a stopping point and I can no figure it out. I have searched online but could not find much. SO does anyone here know how to get the name of a widget?
Code:
def get_children_hover(event):
for widgets in event.widget.winfo_children():
#This is here where I can not seem to figure out how to get the widgets name.
Can someone push me into the right direction.
winfo_children() is the right thing to use but you are using it wrong. It is a method for parent widgets. (i.e. root, frame, canvas etc..)
Also:
If the order doesn’t matter, you can get the same information from the
children widget attribute (it’s a dictionary mapping Tk widget names
to widget instances, so widget.children.values() gives you a list of
instances).
simple example:
import tkinter as tk
def foo():
print ("Frame:", frm.winfo_children())
print ("Root:", root.winfo_children())
print ("children_values:", root.children.values())
root = tk.Tk()
frm = tk.Frame(root)
tk.Label(root,text="foo").pack()
btn = tk.Button(frm,text="FOOO",command=foo)
frm.pack()
btn.pack()
root.mainloop()
about your code:
def get_children_hover(event):
for widgets in root.winfo_children(): #assuming your Tk() instance named root
I want to remove a frame from my interface when a specific button is clicked.
This is the invoked callback function
def removeMyself(self):
del self
However, it doesn't remove itself. I'm probably just deleting the object in python without updating the interface ?
thanks
Update
self.itemFrame = tk.Frame(parent)
self.itemFrame.pack(expand=False, side=tk.TOP)
removeB = tk.Button(self.itemFrame, text="Remove", width=10, command=self.removeIsosurface)
def removeIsosurface(self):
self.itemFrame.Destroy()
Error message:
AttributeError: Frame instance has no attribute 'Destroy'
To remove, call either frm.pack_forget() or frm.grid_forget() depending on whether the frame was packed or grided.
Then call frm.destroy() if you aren't going to use it again, or hold onto the reference and repack or regrid when you want to show it again.
del does not delete anything. del something just removes something from the local scope. And although if something was the only reference to an object, it may allow the object it to be garbage collected in the future, don't even think of using del to delete objects!!! And since self is just a normal variables, del self does nothing, except of course stopping the rest of the method from accessing the instance (so at the end of the method, it's actually like pass).
The exact way to remove a widget from the GUI depends on what geometry manager you use. If you used .grid(), you can use .grid_forget(). Note that this still doesn't destroy the widget - quite the contrary, you can go on and .grid() it again! - but that doesn't make any difference.
Let's say you're making a class. You have to do a couple of things special here:
The frame you want to destroy has to be an instance variable
You have to write a callback (which you did)
So, here's how a basic prototype would look.
from Tkinter import Tk, Frame, Button, Label
class GUI:
def __init__(self, root):
self.root = root # root is a passed Tk object
self.button = Button(self.root, text="Push me", command=self.removethis)
self.button.pack()
self.frame = Frame(self.root)
self.frame.pack()
self.label = Label(self.frame, text="I'll be destroyed soon!")
self.label.pack()
def removethis(self):
self.frame.destroy()
root = Tk()
window = GUI(root)
root.mainloop()
Happy hunting!
wont this help : self.destroy()
chk this out : PY cookbook the last para