[Tutorial] Python GUI Programming Part II

[Acid_Snake]

Now that you know the basics of windows and widgets will see some more useful Tkinter widgets.


Button:
The button widget is used for creating a button that triggers something when the user clicks on it.

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button = Tkinter.Button(main_window, text="This is a button\nClick Me!", command=main)

The three values passed to the button are:
- main_window: the variable of the main window where the button will be placed
- text: the text to be displayed in the button
- command: the function to call when the button is pressed. Be careful because main and main() are very different, when you give a function value it has to be just the name of the function without brackets, otherwise it will autoexecute.


Checkbutton:
A checkbutton is used to allow the user to select a true/false option, it requires the use of IntVar() to keep track of its state:

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from Tkinter import IntVar
checkbutton_variable = IntVar()
checkbutton = Tkinter.Checkbutton(main_window, text="This is a checkbutton", variable=checkbutton_variable)

The only difference with the button widget is the variable value, used to assign a variable that keeps track of the state of the checkbutton (ticked or not), to find the state of the checkbutton we would use:

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checkbutton_variable.get()

This will return 0 if not ticked, 1 if ticked:

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if checkbutton_variable.get() == 0: print "Not Ticked"
elif checkbutton_variable.get() == 1: print "Ticked"

Take good note of the use of IntVar() because you're going to use it in other widgets as well.


Entry:
This widget is used to receive a string from the user.

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entry = Tkinter.Entry(main_window)

As you can see only one value is needed to be passed to this widget.
To get the text inputted by the user:

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entry.get()

Pretty simple right? lets move on...


Radiobutton:
Did you take note about IntVar()? Good cause you're gonna need it for this widget. The radiobutton widget is used to allow the user to choose between two or more values:

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radiobutton_var = IntVar()
radiobutton1 = Tkinter.Radiobutton(main_window, text="Option 1", variable=radiobutton_var, value=1)
radiobutton2 = Tkinter.Radiobutton(main_window, text="Option 2", variable=radiobutton_var, value=2)
radiobutton3 = Tkinter.Radiobutton(main_window, text="Option 3", variable=radiobutton_var, value=3)

The only change here is value, it is important that you give different values to different radiobuttons to be able to identify what the user has selected.


Listbox:
The listbox widget is similar to the radiobutton but the visual is different. This also allows the user to select different values inside a box:

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listbox = Tkinter.Listbox(main_window)
listbox.insert(1, "Option 1")
listbox.insert(2, "Option 2")
listbox.insert(3, "Option 3")

You can also use a list and the for statement:

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list_ = ["option 1", "option 2", "option 3"]
listbox = Tkinter.Listbox(main_window)
for i in list_:
    listbox.insert(1, i)

To get the value used by the user:

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listbox.get()

But I prefer this:

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listbox.get(listbox.curselection()[0])

Spinbox:
This one is used to select a fix amount (i.e. from 0 to 9, from 10 to 100, etc), it is fairly simple:

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spinbox = Tkinter.Spinbox(main_window, from_=0, to=10)

and of couse:

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spinbox.get()

to get the value selected by the user.
Notice how the value is from_ instead of from, this is to distinguish it from python's built-in from found in code like:

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from Tkinter import IntVar

This are the most used widgets but there are more, you can refer to this great site for more widget and examples:
http://www.tutorialspoint.com/python/py ... amming.htm

Now lets put all the above into practice with the following code:

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#! /usr/bin/env python
import Tkinter
from Tkinter import IntVar

def main():

	if checkbutton_variable.get() == 0: print "Checkbutton: not ticked"
	elif checkbutton_variable.get() == 1: print "Checkbutton: ticked"

	print "Entry:", entry.get()

	if radiobutton_var.get() == 0: print "Radiobutton: None selected"
	elif radiobutton_var.get() == 1: print "Radionbutton: Option 1 selected"
	elif radiobutton_var.get() == 2: print "Radionbutton: Option 2 selected"
	elif radiobutton_var.get() == 3: print "Radionbutton: Option 3 selected"

	try: print "Listbox:", listbox.get(listbox.curselection()[0])
	except: print "Listbox: nothing selected"

	print "Spinbox value:", spinbox.get()

main_window = Tkinter.Tk()

checkbutton_variable = IntVar()
checkbutton = Tkinter.Checkbutton(main_window, text="This is a checkbutton", variable=checkbutton_variable)

entry = Tkinter.Entry(main_window)

radiobutton_var = IntVar()
radiobutton1 = Tkinter.Radiobutton(main_window, text="Option 1", variable=radiobutton_var, value=1)
radiobutton2 = Tkinter.Radiobutton(main_window, text="Option 2", variable=radiobutton_var, value=2)
radiobutton3 = Tkinter.Radiobutton(main_window, text="Option 3", variable=radiobutton_var, value=3)

listbox = Tkinter.Listbox(main_window)
list_ = ["Option 1", "Option 2", "Option 3"]
for i in list_:
    listbox.insert(1, i)
#listbox.insert(1, "Option 1")
#listbox.insert(2, "Option 2")
#listbox.insert(3, "Option 3")

spinbox = Tkinter.Spinbox(main_window, from_=0, to=10)

button = Tkinter.Button(main_window, text="This is a button\nClick Me!", command=main)

checkbutton.pack()
entry.pack()
radiobutton1.pack()
radiobutton2.pack()
radiobutton3.pack()
listbox.pack()
spinbox.pack()
button.pack()

main_window.mainloop()

Which will give the following result:

tkinter

tkinter.png (60.07 KiB) Viewed 3350 times

As you can see pressing the button will call the main function, which will give you details about the state of the various widgets.

See you soon...

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