Implementing the Full-Screen Experience
Enabling a window of your app to assume full-screen mode, taking over the entire screen, provides users with a more immersive, cinematic experience. Full-screen appearance can be striking and can make your app stand out. From a practical standpoint, full-screen mode presents a better view of users’ data, enabling them to concentrate fully on their content without the distractions of other apps or the desktop.
In full-screen mode, by default, the menu bar and Dock are autohidden; that is, they are normally hidden but reappear when the user moves the pointer to the top or bottom of the screen. A full-screen window does not draw its titlebar and may have special handling for its toolbar.
The full-screen experience makes sense for many apps but not for all. For example, the Finder, Address Book, and Calculator would not provide any benefit to users by assuming full-screen mode. The same is probably true for most utility apps. Media-rich apps, on the other hand, can often benefit from full-screen presentation.
Beginning with OS X v10.7, Cocoa includes support for full-screen mode through APIs in
NSWindowDelegate protocol. When the user chooses to enter full-screen mode, Cocoa dynamically creates a space and puts the window into that space. This behavior enables the user to have one window of an app running in full-screen mode in one space, while using other windows of that app, as well as other apps, on the desktop in other spaces. While in full-screen mode, the user can switch between windows in the current app or switch apps.
Apps that have implemented full-screen user interfaces in previous versions of OS X should consider standardizing on the full-screen APIs in OS X v10.7.
Full-Screen API in NSApplication
Full-screen support in
NSApplication is provided by the presentation option
NSApplicationPresentationFullScreen. You can find the current presentation mode via the
currentSystemPresentationOptions, which is also key-value observable. You can set the presentation options using the
setPresentationOptions:. (Be sure to observe the restrictions on presentation option combinations documented with
NSApplicationPresentationOptions, and set the presentation options in a try-catch block to ensure that your program does not crash from an invalid combination of options.)
A window delegate may also specify that the window toolbar be removed from the window in full-screen mode and be shown automatically with the menu bar by including
NSApplicationPresentationAutoHideToolbar in the presentation options returned from the
window:willUseFullScreenPresentationOptions: method of
Full-Screen API in NSWindow
The app must specify whether a given window can enter full-screen mode. Apps can set collection behavior using the
setCollectionBehavior: method by passing in various constants, and the current options may be accessed via the
collectionBehavior method. You can choose between two constants to override the window collection behavior, as shown in the following table:
The frontmost window with this collection behavior becomes the full-screen window. A window with this collection behavior has a full-screen button in the upper right of its titlebar.
Windows with this collection behavior can be shown in the same space with the full-screen window.
When a window goes into full-screen mode, the
styleMask changes to
NSFullScreenWindowMask to reflect the state of the window.The setting of the
styleMask goes through the
setStyleMask: method. As a result, a window can override this method if it has customization to do when entering or exiting full-screen.
A window can be taken into or out of full-screen mode using the
toggleFullScreen: method. If an app supports full-screen mode, it should add a menu item to the View menu with
toggleFullScreen: as the action, and
nil as the target.
Full-Screen API in NSWindowDelegate Protocol
The following notifications are sent before and after the window enters and exits full-screen mode:
The window delegate has the following corresponding window delegate notification methods:
NSWindowDelegate protocol methods supporting full-screen mode are listed in Table 3-1.
Invoked to allow the delegate to modify the full-screen content size.
Returns the presentation options the window will use when transitioning to full-screen mode.
Invoked when the window is about to enter full-screen mode. The window delegate can implement this method to customize the animation by returning a custom window or array of windows containing layers or other effects.
The system has started its animation into full-screen mode, including transitioning into a new space. You can implement this method to perform custom animation with the given duration to be in sync with the system animation.
Invoked if the window failed to enter full-screen mode.
Invoked when the window is about to exit full-screen mode. The window delegate can implement this method to customize the animation when the window is about to exit full-screen by returning a custom window or array of windows containing layers or other effects.
The system has started its animation out of full-screen, including transitioning back to the desktop space. You can implement this method to perform custom animation with the given duration to be in sync with the system animation.
Invoked if the window failed to exit full-screen mode.
For more information about full-screen mode, see NSWindowDelegate Protocol Reference and the OS X Human Interface Guidelines.