17. tk Spinbox

See: https://docs.python.org/3/library/tkinter.html#tkinter.Spinbox
See: https://www.geeksforgeeks.org/python-tkinter-spinbox/

17.1. Usage

The tkinter.Spinbox widget allows the user to select a value by either typing it directly or using the up and down arrow buttons.
A spinbox can display a range of numbers or a sequence of strings.
To create a spinbox widget, the general syntax is
(assuming import via import tkinter as tk):
spinbox_widget = tk.Spinbox(parent, option=value)
parent is the window or frame object.
Options can be passed as parameters separated by commas.
A spinbox can be associated with a StringVar, IntVar or DoubleVar control variable.

17.2. Using a Spinbox

../_images/spinbox.png 
import tkinter as tk

root = tk.Tk()
root.title("Spinbox Example")
root.geometry("400x100")

value = tk.IntVar(value=5)

spinbox = tk.Spinbox(
    root,
    from_=0,
    to=10,
    increment=1,
    textvariable=value,
    width=4,
    font=("Arial", 16),
    bg="lightblue",
    fg="blue",
    activebackground="blue",
    borderwidth=1,
    relief="sunken",
    )

spinbox.pack(padx=10, pady=10)

root.mainloop()

Tasks

  1. Modify the code so that the spinbox:

    • displays values of UG, E, D, C, B, A,

    • has a width of 5.

    • has a bg colour of lightgreen.

    • has a fg colour of green.

    • has an activebackground colour of green.

    • has a width of 5.

    • has a borderwidth of 2.

    • has a relief of groove.

    • sets the inital display value to C.

    ../_images/spinbox_question.png

Modify the code to produce the spinbox shown above.

import tkinter as tk

root = tk.Tk()
root.title("Spinbox Question")
root.geometry("400x100")

value = tk.StringVar()

spinbox = tk.Spinbox(
    root,
    values=("UG", "E", "D", "C", "B", "A"),
    textvariable=value,
    width=5,
    font=("Arial", 16),
    bg="lightgreen",
    fg="green",
    activebackground="green",
    borderwidth=2,
    relief="groove",
)

spinbox.pack(padx=10, pady=10)
value.set("C")
root.mainloop()

17.3. Methods

spinbox_widget.delete(first, last=None)
Deletes one or more characters from the entry field.
spinbox_widget.get()
Returns the current value as a string.
spinbox_widget.insert(index, text)
Inserts text into the entry field.
spinbox_widget.icursor(index)
Moves the insertion cursor to the specified position.
spinbox_widget.invoke(element)
Simulates clicking one of the arrow buttons.
element may be "buttonup" or "buttondown".
spinbox_widget.selection('range', start, end)
Selects a range of text.

17.4. Control variable methods

variable.get()
Returns the current value stored in the control variable.
variable.set(value)
Sets the current value of the control variable.
The displayed value updates automatically.

17.5. Parameter syntax

spinbox_widget = tk.Spinbox(parent, option=value)
parent is the window or frame object.
Options can be passed as parameters separated by commas.

Parameters:

activebackground
Syntax: spinbox_widget = tk.Spinbox(parent, activebackground="color")
Description: Sets the background colour of the arrow buttons while active.
Default: SystemButtonFace
background
bg
Syntax: spinbox_widget = tk.Spinbox(parent, bg="color")
Description: Sets the background colour.
Default: SystemWindow
borderwidth
bd
Syntax: spinbox_widget = tk.Spinbox(parent, borderwidth=value)
Description: Sets the border width.
Default: 2
buttonbackground
Syntax: spinbox_widget = tk.Spinbox(parent, buttonbackground="color")
Description: Sets the background colour of the up and down arrow buttons.
Default: SystemButtonFace
command
Syntax: spinbox_widget = tk.Spinbox(parent, command=function)
Description: Calls a function whenever the arrow buttons change the value.
cursor
Syntax: spinbox_widget = tk.Spinbox(parent, cursor="cursor")
Description: Sets the mouse cursor.
disabledbackground
Syntax: spinbox_widget = tk.Spinbox(parent, disabledbackground="color")
Description: Sets the background colour when the widget is disabled.
Default: SystemButtonFace
disabledforeground
Syntax: spinbox_widget = tk.Spinbox(parent, disabledforeground="color")
Description: Sets the text colour when the widget is disabled.
Default: SystemDisabledText
exportselection
Syntax: spinbox_widget = tk.Spinbox(parent, exportselection=boolean)
Description: Determines whether selected text is automatically copied to the clipboard.
Default: 1
font
Syntax: spinbox_widget = tk.Spinbox(parent, font=("font", size, style))
Description: Sets the font used to display the value.
foreground
fg
Syntax: spinbox_widget = tk.Spinbox(parent, fg="color")
Description: Sets the text colour.
format
Syntax: spinbox_widget = tk.Spinbox(parent, format="%format")
Description: Specifies how numeric values are displayed.
from_
Syntax: spinbox_widget = tk.Spinbox(parent, from_=value)
Description: Sets the minimum numeric value.
Default: 0
increment
Syntax: spinbox_widget = tk.Spinbox(parent, increment=value)
Description: Sets the amount added or subtracted each time an arrow button is pressed.
Default: 1
justify
Syntax: spinbox_widget = tk.Spinbox(parent, justify="position")
Description: Aligns the displayed text.
Valid values: left, center and right.
readonlybackground
Syntax: spinbox_widget = tk.Spinbox(parent, readonlybackground="color")
Description: Sets the background colour when state="readonly".
Default: SystemButtonFace
relief
Syntax: spinbox_widget = tk.Spinbox(parent, relief="style")
Description: Sets the border style of the widget.
Default: sunken
repeatdelay
Syntax: spinbox_widget = tk.Spinbox(parent, repeatdelay=milliseconds)
Description: Specifies how long to wait before the value begins auto-repeating while an arrow button is held down.
Default: 400
repeatinterval
Syntax: spinbox_widget = tk.Spinbox(parent, repeatinterval=milliseconds)
Description: Specifies the time between repeated value changes while an arrow button is held down.
Default: 100
state
Syntax: spinbox_widget = tk.Spinbox(parent, state="state")
Description: Sets the widget state.
Valid values: normal, readonly and disabled.
textvariable
Syntax: spinbox_widget = tk.Spinbox(parent, textvariable=variable)
Description: Associates a control variable with the widget.
to
Syntax: spinbox_widget = tk.Spinbox(parent, to=value)
Description: Sets the maximum numeric value.
Default: 0
values
Syntax: spinbox_widget = tk.Spinbox(parent, values=("A", "B", "C"))
Description: Displays a fixed sequence of values instead of a numeric range.
width
Syntax: spinbox_widget = tk.Spinbox(parent, width=value)
Description: Sets the width of the entry field.
wrap
Syntax: spinbox_widget = tk.Spinbox(parent, wrap=True)
Description: Wraps from the maximum value back to the minimum value.
Default: False

17.6. Default options

Code to display the default value for each Spinbox option is shown below.
import tkinter as tk

root = tk.Tk()

widget = tk.Spinbox(root)
widget_options = widget.keys()

for option in widget_options:
    print(f"{option}: {widget.cget(option)}")  # cget retrieves the current value of the option