A sheet is simply an
NSWindow instance that is attached to another window. The sheet comes down over the window, and the window stops getting events until the sheet is dismissed. Typically, you will compose a sheet as an off-screen window in your XIB file.
NSApplication has several methods that make sheets possible:
// Start a sheet- (void)beginSheet:(NSWindow *)sheet modalForWindow:(NSWindow *)docWindow modalDelegate:(id)modalDelegate didEndSelector:(SEL)didEndSelector contextInfo:(void *)contextInfo;// End the sheet- (void)endSheet:(NSWindow *)sheet returnCode:(NSInteger)returnCode;
Besides the sheet window and the window to which it is attached, you supply a modal delegate, a selector, and a