Programming Python, Second Edition

Dialogs

Dialogs are windows popped up by a script to provide or request additional information. They come in two flavors, modal and nonmodal:

• Modal dialogs block the rest of the interface until the dialog window is dismissed; users must reply to the dialog before the program continues.

• Nonmodal dialogs can remain on screen indefinitely without interfering with other windows in the interface; they can usually accept inputs at any time.

Regardless of their modality, dialogs are generally implemented with the Toplevel window object we met in the prior section, whether you make the Toplevel or not. There are essentially three ways to present pop-up dialogs to users with Tkinter: by using common dialog calls, by using the now-dated Dialog object, and by creating custom dialog windows with Toplevels and other kinds of widgets. Let’s explore the basics of all three schemes.

Standard (Common) Dialogs

Because standard dialog calls are simpler, let’s start here first. Tkinter comes with a collection of precoded dialog windows that implement many of the most common pop-ups programs generate -- file selection dialogs, error and warning pop-ups, and question and answer prompts. They are called standard dialogs (and sometimes “common” dialogs), because they are part of the Tkinter library, and use platform-specific library calls to look like they should on each platform. A Tkinter file open dialog, for instance, looks like any other on Windows.

All standard dialog calls are modal (they ...