Tkinter Button
The Button widget is used to add buttons in a Python
application. These buttons can display text or images that convey the purpose
of the buttons. You can attach a function or a method to a button which is
called automatically when you click the button.
Syntax
w=
Button ( master, option=value, ... )
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Parameters
- master: This represents the parent window.
- options: Here is the list of most commonly used
options for this widget. These options can be used as key-value pairs
separated by commas.
Option
|
Description
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activebackground
|
Background color when the
button is under the cursor.
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activeforeground
|
Foreground color when the
button is under the cursor.
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bd
|
Border width in pixels. Default
is 2.
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bg
|
Normal background color.
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command
|
Function or method to be
called when the button is clicked.
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fg
|
Normal foreground (text)
color.
|
font
|
Text font to be used for
the button’s label.
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height
|
Height of the button in
text lines (for textual buttons) or pixels (for images).
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highlightcolor
|
The color of the focus
highlight when the widget has focus.
|
image
|
Image to be displayed on
the button (instead of text).
|
justify
|
How to show multiple text
lines: LEFT to left-justify each line; CENTER to center them; or RIGHT to
right-justify.
|
padx
|
Additional padding left
and right of the text.
|
pady
|
Additional padding above
and below of the text.
|
relief
|
Relief specifies the type
of the border. Some of the values are SUNKEN, RAISED, GROOVE, and RIDGE.
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state
|
Set this option to
DISABLED to gray out the button and make it unresponsive. Has the value
ACTIVE when the mouse is over it. Default is NORMAL.
|
underline
|
Default is -1, meaning
that no character of the text on the button will be underlined. If non-negative,
the corresponding text character will be underlined.
|
width
|
Width of the button in
letters (If displayed text) or pixels (if displaying an image).
|
wraplength
|
If this value is set to a
positive number, the text lines will be wrapped to fit within this length.
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Methods
Following are commonly used methods for this
widget-
Method
|
Description
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flash()
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Causes the button to flash several times between
active and normal colors. Leaves the button in the state it was in
originally. Ignored if the button is disabled.
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invoke()
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Calls the button’s callback, and returns what that
function returns. Has no effect if the button is disabled or there is no
callback.
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Example
#
!/usr/bin/python3
from
tkinter import *
from
tkinter import messagebox
top =
Tk()
top.geometry("100x100")
def
helloCallBack():
msg=messagebox.showinfo( "Hello
Python", "Hello World")
B =
Button(top, text ="Hello", command = helloCallBack)
B.place(x=50,y=50)
top.mainloop( )
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When the above code is executed, it produces the following result-
