I created a Frame and then a Canvas.
What I want to do next is to add a Button on the Canvas.
However, when I packed the Button I cannot see the Canvas!
Here is what I tried:
from Tkinter import Tk, Canvas, Frame, Button
from Tkinter import BOTH, W, NW, SUNKEN, TOP, X, FLAT, LEFT
class Example(Frame):
def __init__(self, parent):
Frame.__init__(self, parent)
self.parent = parent
self.initUI()
def initUI(self):
self.parent.title("Layout Test")
self.config(bg = '#F0F0F0')
self.pack(fill = BOTH, expand = 1)
#create canvas
canvas1 = Canvas(self, relief = FLAT, background = "#D2D2D2",
width = 180, height = 500)
canvas1.pack(side = TOP, anchor = NW, padx = 10, pady = 10)
#add quit button
button1 = Button(canvas1, text = "Quit", command = self.quit,
anchor = W)
button1.configure(width = 10, activebackground = "#33B5E5",
relief = FLAT)
button1.pack(side = TOP)
def main():
root = Tk()
root.geometry('800x600+10+50')
app = Example(root)
app.mainloop()
if __name__ == '__main__':
main()
The Tkinter pack manager tries to resize the parent widget to the correct size to contain its child widgets, and no larger, by default. So the canvas is there - but it's precisely the same size as the button, and thus invisible.
If you want to place a widget on a canvas without causing the canvas to dynamically resize, you want the Canvas.create_window() function:
# ... snip ...
button1 = Button(self, text = "Quit", command = self.quit, anchor = W)
button1.configure(width = 10, activebackground = "#33B5E5", relief = FLAT)
button1_window = canvas1.create_window(10, 10, anchor=NW, window=button1)
This will create your button with upper-left corner at (10, 10) relative to the canvas, without resizing the canvas itself.
Note that you could replace the window argument with a reference to any other Tkinter widget. One caveat, though: the named widget must be a child of the top-level window that contains the canvas, or a child of some widget located in the same top-level window.
you can use button1.place(x=0,y=0) geometry manager instead of pack(side =TOP)
pack resize the master widget to makes it large enough to hold the child widget
http://effbot.org/tkinterbook/pack.htm#Tkinter.Pack.pack_propagate-method
http://effbot.org/tkinterbook/place.htm
I had the exact same problem. There isn't an official way that I know, but here's a way around it:
from Tkinter import *
root = Tk()
def clicked(event):
print("pressed")
canvas1 = Canvas(root, relief = FLAT, background = "#D2D2D2")
canvas1.pack()
buttonBG = canvas1.create_rectangle(0, 0, 100, 30, fill="grey40", outline="grey60")
buttonTXT = canvas1.create_text(50, 15, text="click")
canvas1.tag_bind(buttonBG, "<Button-1>", clicked) ## when the square is clicked runs function "clicked".
canvas1.tag_bind(buttonTXT, "<Button-1>", clicked) ## same, but for the text.
root.mainloop()
