NSWindow

NSWindow is a class in Apple's AppKit framework that represents a top-level window in macOS applications. It provides the window frame, title bar, and window chrome, and serves as the container for an app’s content. NSWindow manages window ordering, visibility, and keyboard focus within an application.

An NSWindow is not a view, but it owns a contentView, which is an NSView that hosts the application's interface. It can also be associated with a contentViewController. Windows may include toolbars and can take several forms, such as standard windows, panels, or utility windows. The window’s features are controlled by a styleMask, which indicates whether the window is closable, resizable, miniaturizable, and whether it has a title bar or other chrome. Window levels determine how windows are stacked relative to one another.

Creation and lifecycle are typically handled with initializers such as initWithContentRect:styleMask:backing:defer:, or via Interface Builder. Methods like orderFront:, makeKeyAndOrderFront:, and orderOut control visibility and which window receives keyboard input. Windows can be miniaturized, deminiaturized, or closed. They support sheets and modal sessions to coordinate user flows with other windows.

Delegation and interaction are mediated through the NSWindowDelegate protocol, which provides callbacks such as windowWillClose:, windowDidResize:, and windowDidMove:. The responder chain and firstResponder status influence keyboard input and event handling, and NSWindowController commonly manages a window’s lifecycle.

Related classes include NSPanel, a subclass used for utility panels. NSWindow is a core component of AppKit, coordinating window management, content display, and user interaction within macOS applications.