UIApplication Class Reference

Properties

For more about Objective-C properties, see “Properties” in The Objective-C Programming Language.

applicationIconBadgeNumber

The number currently set as the badge of the application icon in Springboard.

@property(nonatomic) NSInteger applicationIconBadgeNumber

Discussion

Set to 0 (zero) to hide the badge number. The default is 0.

applicationSupportsShakeToEdit

A Boolean value that determines whether shaking the device displays the undo-redo user interface.

@property(nonatomic) BOOL applicationSupportsShakeToEdit

Discussion

The default value is YES. Set the property to NO if you don’t want your application to display the Undo and Redo buttons when users shake the device.

Related Sample Code

• SimpleUndo

delegate

The delegate of the application object.

@property(nonatomic, assign) id<UIApplicationDelegate> delegate

Discussion

The delegate must adopt the UIApplicationDelegate formal protocol. UIApplication assigns and does not retain the delegate.

Related Sample Code

• iPhoneUnitTests
• WiTap

idleTimerDisabled

A Boolean value that controls whether the idle timer is disabled for the application.

@property(nonatomic, getter=isIdleTimerDisabled) BOOL idleTimerDisabled

Discussion

The default value of this property is NO. When most applications have no touches as user input for a short period, the system puts the device into a “sleep” state where the screen dims. This is done for the purposes of conserving power. However, applications that don't have user input except for the accelerometer—games, for instance—can, by setting this property to YES, disable the “idle timer” to avert system sleep.

Related Sample Code

• aurioTouch
• GKTank

keyWindow

The application’s key window. (read-only)

@property(nonatomic, readonly) UIWindow *keyWindow

Discussion

This property holds the UIWindow object in the windows array that is most recently sent the makeKeyAndVisible message.

See Also

•   @property windows

Related Sample Code

• MoviePlayer

networkActivityIndicatorVisible

A Boolean value that turns an indicator of network activity on or off.

@property(nonatomic, getter=isNetworkActivityIndicatorVisible) BOOL networkActivityIndicatorVisible

Discussion

Specify YES if the application should show network activity and NO if it should not. The default value is NO. A spinning indicator in the status bar shows network activity. The application may explicitly hide or show this indicator.

Related Sample Code

• URLCache

proximitySensingEnabled

A Boolean value that determines whether proximity sensing is enabled. (Deprecated. The properties proximityMonitoringEnabled and proximityState of the UIDevice class are the replacements.)

@property(nonatomic, getter=isProximitySensingEnabled) BOOL proximitySensingEnabled

Discussion

YES if proximity sensing is enabled; otherwise NO. Enabling proximity sensing tells iPhone OS that it may need to blank the screen if the user’s face is near it. Proximity sensing is disabled by default.

statusBarFrame

The frame rectangle defining the area of the status bar. (read-only)

@property(nonatomic, readonly) CGRect statusBarFrame

Discussion

The value of this property is CGRectZero if the status bar is hidden.

See Also

•   @property statusBarHidden
•   @property statusBarStyle

statusBarHidden

A Boolean value that determines whether the status bar is hidden.

@property(nonatomic, getter=isStatusBarHidden) BOOL statusBarHidden

See Also

• – setStatusBarHidden:animated:

statusBarOrientation

The current orientation of the application’s status bar.

@property(nonatomic) UIInterfaceOrientation statusBarOrientation

Discussion

The value of this property is a constant that indicates an orientation of the receiver’s status bar. See UIInterfaceOrientation for details. Setting this property rotates the status bar to the specified orientation without animating the transition. If your application has rotatable window content, however, you should not arbitrarily set status-bar orientation using this method. The status-bar orientation set by this method does not change if the device changes orientation. For more on rotatable window view, see the UIWindow class reference.

See Also

• – setStatusBarOrientation:animated:

statusBarOrientationAnimationDuration

The animation duration in seconds for the status bar during a 90 degree orientation change. (read-only)

@property(nonatomic, readonly) NSTimeInterval statusBarOrientationAnimationDuration

Discussion

You should double the value of this property for a 180 degree orientation change in the status bar.

See Also

• – setStatusBarOrientation:animated:

statusBarStyle

The current style of the status bar.

@property(nonatomic) UIStatusBarStyle statusBarStyle

Discussion

The value of the property is a UIStatusBarStyle constant that indicates the style of status. The default style is UIStatusBarStyleDefault. The animation slides the status bar out for the old orientation and slides it in for the new orientation.

See Also

•   @property statusBarHidden
•   @property statusBarFrame

Related Sample Code

• AlternateViews

windows

The application’s visible windows. (read-only)

@property(nonatomic, readonly) NSArray *windows

Discussion

This property is an array holding the application'€™s visible windows; the windows are ordered back to front.

See Also

•   @property keyWindow

Related Sample Code

• MoviePlayer

Class Methods

sharedApplication

Returns the singleton application instance.

+ (UIApplication *)sharedApplication

Related Sample Code

• AddMusic
• MoviePlayer
• SeismicXML
• SimpleFTPSample
• UICatalog

typedef enum {
   UIInterfaceOrientationPortrait           = UIDeviceOrientationPortrait,
   UIInterfaceOrientationPortraitUpsideDown = UIDeviceOrientationPortraitUpsideDown,
   UIInterfaceOrientationLandscapeLeft      = UIDeviceOrientationLandscapeRight,
   UIInterfaceOrientationLandscapeRight     = UIDeviceOrientationLandscapeLeft
} UIInterfaceOrientation;

typedef enum {
   UIStatusBarStyleDefault,
   UIStatusBarStyleBlackTranslucent,
   UIStatusBarStyleBlackOpaque
} UIStatusBarStyle;

UIKIT_EXTERN NSString *UITrackingRunLoopMode;

UIKIT_EXTERN NSString *const UIApplicationStatusBarOrientationUserInfoKey;
UIKIT_EXTERN NSString *const UIApplicationWillChangeStatusBarFrameNotification;
UIKIT_EXTERN NSString *const UIApplicationDidChangeStatusBarFrameNotification;
UIKIT_EXTERN NSString *const UIApplicationStatusBarFrameUserInfoKey;
UIKIT_EXTERN NSString *const UIApplicationLaunchOptionsURLKey;
UIKIT_EXTERN NSString *const UIApplicationLaunchOptionsSourceApplicationKey;
UIKIT_EXTERN NSString *const UIApplicationLaunchOptionsRemoteNotificationKey;

typedef enum {
   UIRemoteNotificationTypeNone    = 0,
   UIRemoteNotificationTypeBadge   = 1 << 0,
   UIRemoteNotificationTypeSound   = 1 << 1,
   UIRemoteNotificationTypeAlert   = 1 << 2
} UIRemoteNotificationType;

Notifications

All UIApplication notifications are posted by the application instance returned by sharedApplication.

UIApplicationDidBecomeActiveNotification

Posted when the application becomes active.

An application is active when it is receiving events. An active application can be said to have focus. It gains focus after being launched, loses focus when an overlay window pops up or when the device is locked, and gains focus when the device is unlocked.

UIApplicationDidChangeStatusBarFrameNotification

Posted when the frame of the status bar changes.

The userInfo dictionary contains an NSValue object that encapsulates a CGRect structure expressing the location and size of the new status bar frame. Use UIApplicationStatusBarFrameUserInfoKey to access this value.

UIApplicationDidFinishLaunchingNotification

Posted immediately after the application finishes launching.

If the application was launched as a result of in remote notification targeted at it or because another application opened a URL resource claimed the posting application (the notification object), this notification contains a userInfo dictionary. You can access the contents of the dictionary using the UIApplicationLaunchOptionsURLKey and UIApplicationLaunchOptionsSourceApplicationKey constants (for URLs) or the UIApplicationLaunchOptionsRemoteNotificationKey constant (for remote notifications). If the notification was posted for a normal application launch, there is no userInfo dictionary.

UIApplicationDidReceiveMemoryWarningNotification

Posted when the application receives a warning from the operating system about low memory availability.

This notification does not contain a userInfo dictionary.

UIApplicationSignificantTimeChangeNotification

Posted when there is a significant change in time, for example, change to a new day (midnight), carrier time update, and change to or from daylight savings time.

This notification does not contain a userInfo dictionary.

UIApplicationWillChangeStatusBarOrientationNotification

Posted when the application is about to change the orientation of its interface.

The userInfo dictionary contains an NSNumber that encapsulates a UIInterfaceOrientation value (see UIInterfaceOrientation). Use UIApplicationStatusBarOrientationUserInfoKey to access this value.

UIApplicationDidChangeStatusBarOrientationNotification

Posted when the orientation of the application’s user interface changes.

The userInfo dictionary contains an NSNumber object that encapsulates a UIInterfaceOrientation value (see UIInterfaceOrientation). Use UIApplicationStatusBarOrientationUserInfoKey to access this value

UIApplicationWillChangeStatusBarFrameNotification

Posted when the application is about to change the frame of the status bar.

The userInfo dictionary contains an NSValue object that encapsulates a CGRect structure expressing the location and size of the new status bar frame. Use UIApplicationStatusBarFrameUserInfoKey to access this value.

UIApplicationWillResignActiveNotification

Posted when the application is no longer active and loses focus.

An application is active when it is receiving events. An active application can be said to have focus. It gains focus after being launched, loses focus when an overlay window pops up or when the device is locked, and gains focus when the device is unlocked.

UIApplicationWillTerminateNotification

Posted when the application is about to terminate.

This notification does not contain a userInfo dictionary.