Introduction to Sheets

A sheet is simply a dialog attached to a specific window, ensuring that a user never loses track of which window the dialog belongs to. Sheets can be dialogs that require information from the user (such as a Save dialog) or they can be alerts that provide messages about error conditions or warn users of potentially hazardous actions (such as a Save Before Quitting alert).

Alert sheets are document-modal whereas standard alert dialogs are application-modal. A standard alert dialog appears in its own window (technically, an NSPanel object) and allows no user action in the application until the user dismisses the alert. See Dialogs and Special Panels for a discussion of standard alert dialogs.

The “Dialogs” in OS X Human Interface Guidelines section in Apple Human Interface Guidelines discusses sheets from the point of view of how they relate to other OS X user interface objects.

Cocoa developers interested in using sheets in their application should read this document.

Organization of This Document

This programming describes sheets and how they work, and provides examples on how you can use sheets in your applications. It contains the following articles: