Tkinter – listboxes

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The tkinter Listbox widget is a standard GUI element used to display a list of textual options from which a user can select one or more items. It does not natively support images, multiple columns, or built-in scrollbars.

Key Concepts & Usage

Creation: Create a listbox using the Listbox() constructor, specifying a parent window and optional configurations.
Adding Items: Use the .insert() method to add items. .END is a common index to append items to the end of the list.
Selection Modes: The selectmode option determines how many items a user can select:
- .BROWSE (default): Only one item can be selected at a time, and the selection follows the mouse if dragged.
- .SINGLE: Similar to BROWSE, but dragging the mouse doesn’t change the selection; the selection is set on the clicked item.
- .MULTIPLE: Any number of items can be selected by clicking.
- .EXTENDED: Allows selection of multiple, adjacent items by clicking and dragging (or using shift/control keys).
Retrieving Selection: The .curselection() method returns a tuple of the indices of the selected items. To get the actual text, you iterate through the indices and use the .get() method.

Key Configurations and Methods

Configuration/Method	Description
`selectmode`	Determines the selection behavior. Options include `tk.BROWSE` (default, single selection with dragging), `tk.SINGLE` (single selection, no dragging), `tk.MULTIPLE` (multiple selections by clicking), and `tk.EXTENDED` (multiple selections with dragging/range selection).
`.insert(index, *elements)`	Inserts new items at a specific index (e.g., `tk.END` to append to the end).
`.delete(first, last=None)`	Deletes items within a specified range. Use `delete(0, tk.END)` to clear all items.
`.curselection()`	Current Selection – Returns a tuple of indices (0-based line numbers) for the currently selected item(s).
`.get(first, last=None)`	Retrieves the text of the item(s) at the specified index or range.
`.bind('<<ListboxSelect>>', callback)`	Binds a function to the event that occurs whenever the selection changes, which is the recommended way to track selection changes.

Utilising Listbox

We’ll make a meal selection menu:

from tkinter import *

window = Tk()

myList = Listbox(window)
myList.pack()

myList.insert(1,"Pizza")
myList.insert(2,"Pasta")
myList.insert(3,"Schnitzel")
myList.insert(4,"Fish")
myList.insert(5,"Lasagne")

window.mainloop()

We can add colour and styling to our list:

window = Tk()

myList = Listbox(window,
                 bg="#f7ffde",             # Sets background colour
                 font=("Constantia",35),   # changes font face and font size
                 height=8,                 # sets the list to 8 rows
                 width=12                  # sets the width to 12 columns
                 )
myList.pack()

myList.insert(1,"Pizza")
myList.insert(2,"Pasta")
myList.insert(3,"Schnitzel")
myList.insert(4,"Fish")
myList.insert(5,"Lasagne")

window.mainloop()

We can set the height of the Listbox() to precisely match the number of list items in the list with a single line:

window = Tk()

myList = Listbox(window,
                 bg="#f7ffde",             # Sets background colour
                 font=("Constantia",35),   # changes font face and font size
                 width=12                  # sets the width to 12 columns
                 )
myList.pack()

myList.insert(1,"Pizza")
myList.insert(2,"Pasta")
myList.insert(3,"Schnitzel")
myList.insert(4,"Fish")
myList.insert(5,"Lasagne")

myList.config(height=myList.size())       # will dynamically set the height

window.mainloop()

The next thing we’ll want to do is make a selection and SUBMIT an option to order it:

from tkinter import *

# Add SUBMIT function to choose a list item
def submit():
    print("You have ordered: ")
    print(myList.get(myList.curselection()))

window = Tk()

myList = Listbox(window,
                 bg="#f7ffde",
                 font=("Constantia",35),
                 width=12
                 )
myList.pack()

myList.insert(1,"Pizza")
myList.insert(2,"Pasta")
myList.insert(3,"Schnitzel")
myList.insert(4,"Fish")
myList.insert(5,"Lasagne")

myList.config(height=myList.size())    # dynamically sets the height

# Add SUBMIT button to choose a list item - this the runs the "submit" function
submitButton = Button(window,text="Submit",command=submit)
submitButton.pack()

window.mainloop()

Now we’ll add a feature to insert another item to the listbox after the program is compiled and already running, so we will create an entry box within our window where we can add a custom item to this menu:

from tkinter import *

def submit():
    print("You have ordered: ")
    print(myList.get(myList.curselection()))

def addItem():
    myList.insert(myList.size(),entryBox.get())
    # myList.size gets the next list number
    myList.config(height=myList.size())  # dynamically reset the height

window = Tk()

myList = Listbox(window,
                 bg="#f7ffde",
                 font=("Constantia",35),
                 width=12
                 )
myList.pack()

myList.insert(1,"Pizza")
myList.insert(2,"Pasta")
myList.insert(3,"Schnitzel")
myList.insert(4,"Fish")
myList.insert(5,"Lasagne")

myList.config(height=myList.size()) # We leave this line for initial dynamic height setting

# Adds an ENTRY BOX (text field) for new Items to by typed in
entryBox = Entry(window)
entryBox.pack()
# Adds the ADD button to run the ADD function "addItem" at the top of this code
addButton = Button(window,text="Add",command=addItem)
addButton.pack()

submitButton = Button(window,text="Submit",command=submit)
submitButton.pack()

window.mainloop()

To finish up we can create a DELETE button to remove an item from the menu.

from tkinter import *

def submit():
    print("You have ordered: ")
    print(myList.get(myList.curselection()))

def addItem():
    myList.insert(myList.size(),entryBox.get())
    # myList.size gets the next list number
    myList.config(height=myList.size())  # will dynamically set the height to show new item

def deleteItem():
    myList.delete(myList.curselection())
    myList.config(height=myList.size())  # will dynamically reset the height as it shrinks

window = Tk()

myList = Listbox(window,
                 bg="#f7ffde",
                 font=("Constantia",35),
                 width=12
                 )
myList.pack()

myList.insert(1,"Pizza")
myList.insert(2,"Pasta")
myList.insert(3,"Schnitzel")
myList.insert(4,"Fish")
myList.insert(5,"Lasagne")

myList.config(height=myList.size())

entryBox = Entry(window)
entryBox.pack()

submitButton = Button(window,text="Submit",command=submit)
submitButton.pack()

addButton = Button(window,text="Add",command=addItem)
addButton.pack()

# Add a button to run a "deleteItem" function that removes selected item
deleteButton = Button(window,text="Delete",command=deleteItem)
deleteButton.pack()

window.mainloop()

Finally, what if you want to select more than one item from the listbox? We need to use an option called selectmode.

from tkinter import *

def submit():
    yourSelection = []  # Create a LIST (array) called "yourSelection"
    for index in myList.curselection(): # We need a loop to read data into the LIST
        yourSelection.insert(index,myList.get(index))
    print("You have ordered: ")
    for index in yourSelection:  # We need a loop to write the LIST data to screen
        print(index)

def addItem():
    myList.insert(myList.size(),entryBox.get())
    # myList.size gets the next list number
    myList.config(height=myList.size())  # will dynamically reset the height

def deleteItem():
    for index in reversed(myList.curselection()): # Loop to delete MULTIPLE selections
        myList.delete(index)
    myList.config(height=myList.size())  # will dynamically reset the height

window = Tk()

myList = Listbox(window,
                 bg="#f7ffde",
                 font=("Constantia",35),
                 width=12,
                 selectmode=MULTIPLE  # Allows MULTIPLE item selection
                 )
myList.pack()

myList.insert(1,"Pizza")
myList.insert(2,"Pasta")
myList.insert(3,"Schnitzel")
myList.insert(4,"Fish")
myList.insert(5,"Lasagne")

myList.config(height=myList.size())

entryBox = Entry(window)
entryBox.pack()

submitButton = Button(window,text="Submit",command=submit)
submitButton.pack()

addButton = Button(window,text="Add",command=addItem)
addButton.pack()

deleteButton = Button(window,text="Delete",command=deleteItem)
deleteButton.pack()

window.mainloop()

Paste the above code into your IDE and see it working.

A final example to demonstrate more styling settings:

from tkinter import *

def get_selected_item():
    # Get the index of the selected item(s)
    selection_indices = listbox.curselection()
    if selection_indices:
        # Get the actual value using the index
        selected_item = listbox.get(selection_indices[0])
        print(f"Selected item: {selected_item}")
    else:
        print("No item selected.")

root = Tk()
root.title("Tkinter Listbox Example")

# Create a frame to hold the listbox and scrollbar
frame = Frame(root)
frame.pack(padx=10, pady=10, fill=BOTH, expand=True)

# Create a Scrollbar
scrollbar = Scrollbar(frame, orient=VERTICAL)

# Create the Listbox and link it to the scrollbar
listbox = Listbox(frame, yscrollcommand=scrollbar.set, selectmode=SINGLE)
scrollbar.config(command=listbox.yview)

# Pack the scrollbar and listbox
scrollbar.pack(side=RIGHT, fill=Y)
listbox.pack(side=LEFT, fill=BOTH, expand=True)

# Add items to the listbox
items = ["Python", "Perl", "C", "PHP", "JSP", "Ruby", "Java", "C++"]
for item in items:
    listbox.insert(END, item) # Insert at the end

# Create a button to get the selected item
button = Button(root, text="Get Selected Item", command=get_selected_item)
button.pack(pady=10)

root.mainloop()

Tkinter – listboxes

Key Knowledge