Tkinter OptionMenu

Summary: in this tutorial, you’ll learn about the Tkinter OptionMenu widget to display a set of options in a drop-down menu.

Introduction to the Tkinter OptionMenu widget

The OptionMenu widget provides you with a predefined set of options in a drop-down menu.

To create a new OptionMenu widget, you use the OptionMenu constructor:

OptionMenu(container, variable, default=None, *values, **kwargs)Code language: Python (python)

The OptionMenu constructor accepts a number of parameters:

• container is the parent widget of the OptionMenu widget.
• variable is a tk.StringVar object that holds the currently selected option of the OptionMenu.
• default is the default option that the widget displays initially.
• values is a list of values that appear on the drop-down menu.
• kwargs is the widget-specific configuration.

The OptionMenu allows you to change the direction of the drop-down menu via the direction option. The valid directions are 'above', 'below', 'left', 'right', or 'flush'.

The OptionMenu widget also supports the command option. This allows you to assign a callback that will be called after an item is selected.

Like other ttk widgets, you can specify the style name for the OptionMenu using the style option.

Tkinter OptionMenu widget example

The following example illustrates how to use an OptionMenu widget. When you select an item, it’ll show your selection in a label:

import tkinter as tk
from tkinter import ttk


class App(tk.Tk):
    def __init__(self):
        super().__init__()
        self.geometry("320x80")
        self.title('Tkinter OptionMenu Widget')

        # initialize data
        self.languages = ('Python', 'JavaScript', 'Java',
                        'Swift', 'GoLang', 'C#', 'C++', 'Scala')

        # set up variable
        self.option_var = tk.StringVar(self)

        # create widget
        self.create_wigets()

    def create_wigets(self):
        # padding for widgets using the grid layout
        paddings = {'padx': 5, 'pady': 5}

        # label
        label = ttk.Label(self,  text='Select your most favorite language:')
        label.grid(column=0, row=0, sticky=tk.W, **paddings)

        # option menu
        option_menu = ttk.OptionMenu(
            self,
            self.option_var,
            self.languages[0],
            *self.languages,
            command=self.option_changed)

        option_menu.grid(column=1, row=0, sticky=tk.W, **paddings)

        # output label
        self.output_label = ttk.Label(self, foreground='red')
        self.output_label.grid(column=0, row=1, sticky=tk.W, **paddings)

    def option_changed(self, *args):
        self.output_label['text'] = f'You selected: {self.option_var.get()}'


if __name__ == "__main__":
    app = App()
    app.mainloop()Code language: Python (python)

Output:

How it works.

First, define a list of strings used for displaying on the OptionMenu widget:

self.languages = ('Python', 'JavaScript', 'Java', 'Swift', 'GoLang', 'C#', 'C++', 'Scala')Code language: Python (python)

Second, define a ttk.StringVar() object that holds the currently selected item of the OptionMenu in the __init__() method:

self.option_var = tk.StringVar(self)Code language: Python (python)

Third, create a new instance of the OptionMenu widget:

option_menu = ttk.OptionMenu(
    self,
    self.option_var,
    self.languages[0],
    *self.languages,
    command=self.option_changed)Code language: Python (python)

Note that if you skip the default value self.languages[0], the first item of the OptionMenu will vanish.

The option_changed() method will be executed after an item is selected. The method sets the text for the output_label to the selected item:

self.output_label['text'] = f'You selected: {self.option_var.get()}'Code language: PHP (php)

Summary

• Use Tkinter OptionMenu widget to provide users with a fixed set of choices in a drop-down menu.
• Always specify the default value for the OptionMenu constructor.