GUI in Python Using Tkinter

GUI in Python

Python libraries to create Graphical Interfaces :

Tkinter
Python QT
wxPython
Kivy

Tkinter is an inbuilt Python module used to create simple GUI apps.

Tk provides following widgets :

button
canvas
checkbutton
Combobox
entry
frame
label
labelframe
listbox
menu
menubutton
message
notebook
tk_optionmenu
panedwindow
progressbar
radiobutton
scale
scrollbar
separator
sizegrip
spinbox
text
treeview

It provided the following top-level windows :

tk_chooseColor
tk_chooseDirectory
tk_dialog
tk_getOpenFile
tk_getSaveFile
tk_messageBox
tk_popup
toplevel

Tk also provides three geometry managers :

place - It positions widgets at absolute locations
grid - It arranges widgets in a grid
pack - It packs widgets into a cavity

Basics of tkinter

import tkinter module
create the main window (container)
Add any number of widgets to the main window
Enter the main event loop

Eg.

import tkinter
window = Tkinter.Tk()          # creates main window
window.title("GUI")
label = tkinter.Label(window , text="Hello World !!").pack()
window.mainloop()

mainloop() is used when our application is ready to run. mainloop() is an infinite loop used to run the application, wait for an event to occur and process the event till the window is not closed.

Widgets

Button

It is used to add a button in our application.

window = Button(master, option=value)

master represents the parent window.

activebackground : sets the background color when button is under the cursor.

activeforeground : sets the foreground color when button is under the cursor.

bg : sets normal background color

fg : sets the foreground color

command : to call a function

font : sets the font of button label

image : sets the image on the button

width : sets the width of the button

height : sets the height of the button

justify : LEFT , RIGHT , CENTER

import tkinter as tk
window = tk.Tk()
window.title("Python")
button = tk.Button(window , text = 'GUI',width = 25,command = window.destroy)
button.pack()
window.mainloop()

Output is :

Label

It is used to display text or image.

window = Label(master,option=value)

bg : sets the normal background color
command : to call a function
font : sets the font of Label text
image : sets the image on the Label
width : sets the width of the Label

height : sets the height of the Label

from tkinter import *
root = Tk()
l1 = Label(root,text="GUI Python",bg="pink",width = 25)
l1.pack()
root.mainloop()

Output is :

Entry

(Text Field)

It is used to input single line of text.

window = Entry(master,option=value)

bg : sets the background color

fg : sets the foreground color

font : sets the font for widget

justify : LEFT , RIGHT , CENTER

command : to call a function

width : sets the width of widget

height : sets the height of widget

show : Normally, the characters that the user types appear in the entry. To make a .password. entry that echoes each character as (show = "*")

Methods of Entry

delete(start,end) : delete a character or range of characters

get() : returns the text of widget

insert(index,string) : inserts text at the specified index

select_range(start,end) : selects specified range.

select_present() : returns True if there is a selection,false otherwise

from tkinter import *
master = Tk()
l1=Label(master,text='first Name')
l1.grid(row=0)
l2=Label(master,text='Last Name')
l2.grid(row=1)
e1=Entry(master)
e2=Entry(master)
e1.grid(row=0,column=1)
e2.grid(row=1,column=1)
mainloop()

Output is :

Text

It is used to edit multi line text and formate the way it has to be displayed.

t = Text(master,option = value)

highlightcolor : set the color of focus highlight

insertbackground : set the background of the widget

bg : sets the normal background color

fg : sets the foreground color

bd : sets width of the border around the widget. (Default is 2 pixels)

font : sets the font

image : sets the image

width : sets the width (in pixels)

height : sets the height (in lines)

from tkinter import *
root = Tk()
t = Text(root , height = 4,width=40)
t.pack()
t.insert(END,'ANJALI KUMAWAT \nCOMPUTER SCIENCE UNDERGRAD \nGWOC"21" CONTRIBUTOR')
mainloop()

Output is :

Methods of Text

delete(start,end) - deletes a specific character or a range of text
get(start,end) - returns a specific character or a range of text
insert(index,string) - inserts text at the specified index

CheckButton

It is used to display a number of options to a user as toggle buttons.

window = CheckButton(master , option = value)

bg : sets background color

fg : sets foreground color

command : to call a function

font : sets the font

image : sets the image

cffvalue : A checkbutton's associated control variable will be set to 0 when it is cleared(off).We can supply an alternate value for the off state.

onvalue : A checkbutton's associated control variable will be set to 1 when it is set(on).We can supply an alternate value for the on state.

state : Default is state=NORMAL but we can use state=DISANLED to grey out the control and make is unresponsive.

variable : This is control variable associated with checkbutton that tracks the current state of widget.Normally this variable is an IntVar and 0 means cleared and 1 means set.

Width : sets the width of widget.

Methods of checkbutton

Deselect() - clears the checkbutton
Select() - selects the checkbutton
Toggle() - reverses the state(on/off)

from tkinter import *
root = Tk()
var1 = IntVar()
var2 = IntVar()
c1 = Checkbutton(root,text = "like Mango ? ",variable = var1,onvalue = 1,offvalue = 0,width = 40)
c2 = Checkbutton(root,text = "like Orange ? ",variable = var2,onvalue = 1,offvalue = 0,width = 40)
c1.pack()
c2.pack()
root.mainloop()

Output is :

RadioButton

It is used to offer multiple choice option to the used and user can select one option.

window = RadioButton(master,option=value)

bg : sets the background color

fg : sets foreground color

command : to call a function

font : sets the font

image : sets the image

width : sets the width

variable : variable associated with the Radiobuttons.

value : when a radiobutton is selected by user,its control variable is set to its associated value. If the control variable is an IntVar , give each radiobutton in the group a different integer value option. If the control variable is a StringVar,give each radiobutton a different string value option.

Methods of Radiobutton

select() - selects Radiobutton
deselect() - deselects Radiobutton

from tkinter import *

def select():
    if choice.get()==1:
        order = "Large Pizza"
    elif choice.get()==2:
        order = "Medium Pizza"
    else:
        order = "Small Pizza"
    selection = "You have ordered "+order
    label.config(text=selection)

root = Tk()
root.title("Pizza Corner")
choice = IntVar()
rbLarge = Radiobutton(root, text = "Large Pizza",font=20,variable=choice,value=1,command=select)
rbMedium = Radiobutton(root, text = "Medium Pizza",font=20,variable=choice,value=2,command=select)
rbSmall = Radiobutton(root, text = "Small Pizza",font=20,variable=choice,value=3,command=select)
rbLarge.pack(anchor=W)
rbMedium.pack(anchor=W)
rbSmall.pack(anchor=W)
label = Label(root,text="Choose pizza that you want!!",font=35)
label.pack()
mainloop()

Output is :

When we are not clicking on any RadioButton -

If we are clicking on any RadioButton then -

SpinBox

It is used to select a value from fixed number of values.

window = Spinbox(root,option=value)

bg : sets the background color

fg : sets foreground color

font : sets the font

justify : LEFT,RIGHT,CENTER

width : sets the width for widget

from_ : sets the minimum value

to : sets the maximum value

Methods for Spinbox

get() - returns the value

from tkinter import *

def select():
    string = "Selection is "+str(sp.get())
    l.config(text=string)

root = Tk()
sp = Spinbox(root,from_=0,to=10,command=select,width = 15,font=30)
sp.pack()
l=Label(root,text=" ")
l.pack()
mainloop()

Output is :