Struct UIApplication

#[repr(C)]
pub struct UIApplication { /* private fields */ }

Available on crate features UIApplication and UIResponder only.

Apple’s documentation

Implementations

impl UIApplication

pub fn main( principal_class_name: Option<&NSString>, delegate_class_name: Option<&NSString>, mtm: MainThreadMarker, ) -> !

The entry point to UIKit applications.

Creates the application object and the application delegate and sets up the event cycle.

See Apple’s documentation for more details.

Example

Create an application delegate and launch the application.

use objc2::MainThreadMarker;
use objc2::rc::{Allocated, Retained};
use objc2::{define_class, msg_send, ClassType, DefinedClass, MainThreadOnly};
use objc2_foundation::{NSNotification, NSObject, NSObjectProtocol, NSString};
use objc2_ui_kit::{UIApplication, UIApplicationDelegate};

#[derive(Default)]
struct AppState {
    // Whatever state you want to store in your delegate.
}

define_class!(
    // SAFETY:
    // - `NSObject` does not have any subclassing requirements.
    // - `AppDelegate` does not implement `Drop`.
    #[unsafe(super(NSObject))]
    #[thread_kind = MainThreadOnly]
    #[ivars = AppState]
    struct AppDelegate;

    impl AppDelegate {
        // Called by `UIApplication::main`.
        #[unsafe(method_id(init))]
        fn init(this: Allocated<Self>) -> Retained<Self> {
            let this = this.set_ivars(AppState::default());
            unsafe { msg_send![super(this), init] }
        }
    }

    unsafe impl NSObjectProtocol for AppDelegate {}

    unsafe impl UIApplicationDelegate for AppDelegate {
        #[unsafe(method(applicationDidFinishLaunching:))]
        fn did_finish_launching(&self, _notification: &NSNotification) {
            println!("did finish launching!");

            // Do UI initialization in here, such as creating windows, views, etc.
        }

        #[unsafe(method(applicationWillTerminate:))]
        fn will_terminate(&self, _notification: &NSNotification) {
            println!("will terminate!");

            // Tear down your application state here.
        }
    }
);

fn main() {
    let mtm = MainThreadMarker::new().unwrap();
    let delegate_class = NSString::from_class(AppDelegate::class());
    UIApplication::main(None, Some(&delegate_class), mtm);
}

impl UIApplication

pub fn sharedApplication(mtm: MainThreadMarker) -> Retained<UIApplication>

pub unsafe fn delegate( &self, ) -> Option<Retained<ProtocolObject<dyn UIApplicationDelegate>>>

pub unsafe fn setDelegate( &self, delegate: Option<&ProtocolObject<dyn UIApplicationDelegate>>, )

Setter for delegate.

pub unsafe fn beginIgnoringInteractionEvents(&self)

👎Deprecated: Use UIView’s userInteractionEnabled property instead

pub unsafe fn endIgnoringInteractionEvents(&self)

👎Deprecated: Use UIView’s userInteractionEnabled property instead

pub unsafe fn isIgnoringInteractionEvents(&self) -> bool

👎Deprecated: Use UIView’s userInteractionEnabled property instead

pub unsafe fn isIdleTimerDisabled(&self) -> bool

pub unsafe fn setIdleTimerDisabled(&self, idle_timer_disabled: bool)

Setter for isIdleTimerDisabled.

pub unsafe fn openURL(&self, url: &NSURL) -> bool

👎Deprecated

pub unsafe fn canOpenURL(&self, url: &NSURL) -> bool

pub unsafe fn openURL_options_completionHandler( &self, url: &NSURL, options: &NSDictionary<UIApplicationOpenExternalURLOptionsKey, AnyObject>, completion: Option<&DynBlock<dyn Fn(Bool)>>, )

Available on crate feature block2 only.

pub unsafe fn sendEvent(&self, event: &UIEvent)

Available on crate feature UIEvent only.

pub unsafe fn keyWindow(&self) -> Option<Retained<UIWindow>>

👎Deprecated: Should not be used for applications that support multiple scenes as it returns a key window across all connected scenes

Available on crate features UIView and UIWindow only.

pub fn windows(&self) -> Retained<NSArray<UIWindow>>

👎Deprecated: Use UIWindowScene.windows on a relevant window scene instead

Available on crate features UIView and UIWindow only.

pub unsafe fn sendAction_to_from_forEvent( &self, action: Sel, target: Option<&AnyObject>, sender: Option<&AnyObject>, event: Option<&UIEvent>, ) -> bool

Available on crate feature UIEvent only.

pub unsafe fn isNetworkActivityIndicatorVisible(&self) -> bool

👎Deprecated: Provide a custom network activity UI in your app if desired.

pub unsafe fn setNetworkActivityIndicatorVisible( &self, network_activity_indicator_visible: bool, )

👎Deprecated: Provide a custom network activity UI in your app if desired.

Setter for isNetworkActivityIndicatorVisible.

pub unsafe fn supportedInterfaceOrientationsForWindow( &self, window: Option<&UIWindow>, ) -> UIInterfaceOrientationMask

Available on crate features UIOrientation and UIView and UIWindow only.

pub unsafe fn statusBarOrientationAnimationDuration(&self) -> NSTimeInterval

👎Deprecated: Use viewWillTransitionToSize:withTransitionCoordinator: instead.

pub fn statusBarFrame(&self) -> CGRect

👎Deprecated: Use the statusBarManager property of the window scene instead.

Available on crate feature objc2-core-foundation only.

pub unsafe fn applicationIconBadgeNumber(&self) -> NSInteger

👎Deprecated: Use -[UNUserNotificationCenter setBadgeCount:withCompletionHandler:] instead.

pub unsafe fn setApplicationIconBadgeNumber( &self, application_icon_badge_number: NSInteger, )

👎Deprecated: Use -[UNUserNotificationCenter setBadgeCount:withCompletionHandler:] instead.

Setter for applicationIconBadgeNumber.

pub unsafe fn applicationSupportsShakeToEdit(&self) -> bool

pub unsafe fn setApplicationSupportsShakeToEdit( &self, application_supports_shake_to_edit: bool, )

Setter for applicationSupportsShakeToEdit.

pub unsafe fn applicationState(&self) -> UIApplicationState

pub unsafe fn backgroundTimeRemaining(&self) -> NSTimeInterval

pub unsafe fn beginBackgroundTaskWithExpirationHandler( &self, handler: Option<&DynBlock<dyn Fn()>>, ) -> UIBackgroundTaskIdentifier

Available on crate feature block2 only.

pub unsafe fn beginBackgroundTaskWithName_expirationHandler( &self, task_name: Option<&NSString>, handler: Option<&DynBlock<dyn Fn()>>, ) -> UIBackgroundTaskIdentifier

Available on crate feature block2 only.

pub unsafe fn endBackgroundTask(&self, identifier: UIBackgroundTaskIdentifier)

pub unsafe fn setMinimumBackgroundFetchInterval( &self, minimum_background_fetch_interval: NSTimeInterval, )

👎Deprecated: Use a BGAppRefreshTask in the BackgroundTasks framework instead

The system guarantees that it will not wake up your application for a background fetch more frequently than the interval provided. Set to UIApplicationBackgroundFetchIntervalMinimum to be woken as frequently as the system desires, or to UIApplicationBackgroundFetchIntervalNever (the default) to never be woken for a background fetch.

This setter will have no effect unless your application has the “fetch” UIBackgroundMode. See the UIApplicationDelegate method application:performFetchWithCompletionHandler: for more.

pub unsafe fn backgroundRefreshStatus(&self) -> UIBackgroundRefreshStatus

When background refresh is available for an application, it may launched or resumed in the background to handle significant location changes, remote notifications, background fetches, etc. Observe UIApplicationBackgroundRefreshStatusDidChangeNotification to be notified of changes.

pub unsafe fn isProtectedDataAvailable(&self) -> bool

pub unsafe fn userInterfaceLayoutDirection( &self, ) -> UIUserInterfaceLayoutDirection

Available on crate feature UIInterface only.

pub unsafe fn preferredContentSizeCategory( &self, ) -> Retained<UIContentSizeCategory>

Available on crate feature UIContentSizeCategory only.

pub unsafe fn connectedScenes(&self) -> Retained<NSSet<UIScene>>

Available on crate feature UIScene only.

pub unsafe fn openSessions(&self) -> Retained<NSSet<UISceneSession>>

Available on crate feature UISceneSession only.

pub unsafe fn supportsMultipleScenes(&self) -> bool

pub unsafe fn activateSceneSessionForRequest_errorHandler( &self, request: &UISceneSessionActivationRequest, error_handler: Option<&DynBlock<dyn Fn(NonNull<NSError>)>>, )

Available on crate features UISceneSessionActivationRequest and block2 only.

Asks the system to activate an existing scene, or create a new scene and associate it with your app.

• Parameters:
• request: The activation request.
• errorHandler: A handler to be called if the request fails.

pub unsafe fn requestSceneSessionActivation_userActivity_options_errorHandler( &self, scene_session: Option<&UISceneSession>, user_activity: Option<&NSUserActivity>, options: Option<&UISceneActivationRequestOptions>, error_handler: Option<&DynBlock<dyn Fn(NonNull<NSError>)>>, )

👎Deprecated: Please use activateSceneSessionForRequest:errorHandler:

Available on crate features UISceneOptions and UISceneSession and block2 only.

pub unsafe fn requestSceneSessionDestruction_options_errorHandler( &self, scene_session: &UISceneSession, options: Option<&UISceneDestructionRequestOptions>, error_handler: Option<&DynBlock<dyn Fn(NonNull<NSError>)>>, )

Available on crate features UISceneOptions and UISceneSession and block2 only.

pub unsafe fn requestSceneSessionRefresh(&self, scene_session: &UISceneSession)

Available on crate feature UISceneSession only.

impl UIApplication

Methods declared on superclass NSObject.

pub unsafe fn init(this: Allocated<Self>) -> Retained<Self>

pub unsafe fn new(mtm: MainThreadMarker) -> Retained<Self>

impl UIApplication

UIRemoteNotifications.

pub unsafe fn registerForRemoteNotifications(&self)

pub unsafe fn unregisterForRemoteNotifications(&self)

pub unsafe fn isRegisteredForRemoteNotifications(&self) -> bool

pub unsafe fn registerForRemoteNotificationTypes( &self, types: UIRemoteNotificationType, )

👎Deprecated: Use -[UIApplication registerForRemoteNotifications] and UserNotifications Framework’s -[UNUserNotificationCenter requestAuthorizationWithOptions:completionHandler:]

pub unsafe fn enabledRemoteNotificationTypes(&self) -> UIRemoteNotificationType

👎Deprecated: Use -[UIApplication isRegisteredForRemoteNotifications] and UserNotifications Framework’s -[UNUserNotificationCenter getNotificationSettingsWithCompletionHandler:] to retrieve user-enabled remote notification and user notification settings

impl UIApplication

UILocalNotifications.

pub unsafe fn presentLocalNotificationNow( &self, notification: &UILocalNotification, )

👎Deprecated: Use UserNotifications Framework’s -[UNUserNotificationCenter addNotificationRequest:withCompletionHandler:]

Available on crate feature UILocalNotification only.

pub unsafe fn scheduleLocalNotification( &self, notification: &UILocalNotification, )

👎Deprecated: Use UserNotifications Framework’s -[UNUserNotificationCenter addNotificationRequest:withCompletionHandler:]

Available on crate feature UILocalNotification only.

pub unsafe fn cancelLocalNotification(&self, notification: &UILocalNotification)

👎Deprecated: Use UserNotifications Framework’s -[UNUserNotificationCenter removePendingNotificationRequestsWithIdentifiers:]

Available on crate feature UILocalNotification only.

pub unsafe fn cancelAllLocalNotifications(&self)

👎Deprecated: Use UserNotifications Framework’s -[UNUserNotificationCenter removeAllPendingNotificationRequests]

pub unsafe fn scheduledLocalNotifications( &self, ) -> Option<Retained<NSArray<UILocalNotification>>>

👎Deprecated: Use UserNotifications Framework’s -[UNUserNotificationCenter getPendingNotificationRequestsWithCompletionHandler:]

Available on crate feature UILocalNotification only.

pub unsafe fn setScheduledLocalNotifications( &self, scheduled_local_notifications: Option<&NSArray<UILocalNotification>>, )

👎Deprecated: Use UserNotifications Framework’s -[UNUserNotificationCenter getPendingNotificationRequestsWithCompletionHandler:]

Available on crate feature UILocalNotification only.

Setter for scheduledLocalNotifications.

impl UIApplication

UIUserNotificationSettings.

pub unsafe fn registerUserNotificationSettings( &self, notification_settings: &UIUserNotificationSettings, )

👎Deprecated: Use UserNotifications Framework’s -[UNUserNotificationCenter requestAuthorizationWithOptions:completionHandler:] and -[UNUserNotificationCenter setNotificationCategories:]

Available on crate feature UIUserNotificationSettings only.

pub unsafe fn currentUserNotificationSettings( &self, ) -> Option<Retained<UIUserNotificationSettings>>

👎Deprecated: Use UserNotifications Framework’s -[UNUserNotificationCenter getNotificationSettingsWithCompletionHandler:] and -[UNUserNotificationCenter getNotificationCategoriesWithCompletionHandler:]

Available on crate feature UIUserNotificationSettings only.

impl UIApplication

UIRemoteControlEvents.

pub unsafe fn beginReceivingRemoteControlEvents(&self)

pub unsafe fn endReceivingRemoteControlEvents(&self)

impl UIApplication

UINewsstand.

pub unsafe fn setNewsstandIconImage(&self, image: Option<&UIImage>)

👎Deprecated: Newsstand apps now behave like normal apps on SpringBoard

Available on crate feature UIImage only.

impl UIApplication

UIShortcutItems.

pub unsafe fn shortcutItems( &self, ) -> Option<Retained<NSArray<UIApplicationShortcutItem>>>

Available on crate feature UIApplicationShortcutItem only.

pub unsafe fn setShortcutItems( &self, shortcut_items: Option<&NSArray<UIApplicationShortcutItem>>, )

Available on crate feature UIApplicationShortcutItem only.

Setter for shortcutItems.

impl UIApplication

UIAlternateApplicationIcons.

pub unsafe fn supportsAlternateIcons(&self) -> bool

pub unsafe fn setAlternateIconName_completionHandler( &self, alternate_icon_name: Option<&NSString>, completion_handler: Option<&DynBlock<dyn Fn(*mut NSError)>>, )

Available on crate feature block2 only.

pub unsafe fn alternateIconName(&self) -> Option<Retained<NSString>>

impl UIApplication

UIStateRestoration.

pub unsafe fn extendStateRestoration(&self)

pub unsafe fn completeStateRestoration(&self)

pub unsafe fn ignoreSnapshotOnNextApplicationLaunch(&self)

pub unsafe fn registerObjectForStateRestoration_restorationIdentifier( object: &ProtocolObject<dyn UIStateRestoring>, restoration_identifier: &NSString, )

Available on crate feature UIStateRestoration only.

impl UIApplication

This impl block contains no items.

DefaultApplication.

impl UIApplication

UIApplicationDeprecated.

pub unsafe fn isProximitySensingEnabled(&self) -> bool

👎Deprecated

pub unsafe fn setProximitySensingEnabled(&self, proximity_sensing_enabled: bool)

👎Deprecated

Setter for isProximitySensingEnabled.

pub unsafe fn setStatusBarHidden_animated(&self, hidden: bool, animated: bool)

👎Deprecated: Use -[UIViewController prefersStatusBarHidden]

pub unsafe fn setStatusBarOrientation( &self, status_bar_orientation: UIInterfaceOrientation, )

👎Deprecated: Explicit setting of the status bar orientation is more limited in iOS 6.0 and later

Available on crate feature UIOrientation only.

Setter for [statusBarOrientation][Self::statusBarOrientation].

pub unsafe fn setStatusBarOrientation_animated( &self, interface_orientation: UIInterfaceOrientation, animated: bool, )

👎Deprecated: Explicit setting of the status bar orientation is more limited in iOS 6.0 and later

Available on crate feature UIOrientation only.

pub unsafe fn setStatusBarStyle(&self, status_bar_style: UIStatusBarStyle)

👎Deprecated: Use -[UIViewController preferredStatusBarStyle]

Setter for [statusBarStyle][Self::statusBarStyle].

pub unsafe fn setStatusBarStyle_animated( &self, status_bar_style: UIStatusBarStyle, animated: bool, )

👎Deprecated: Use -[UIViewController preferredStatusBarStyle]

pub unsafe fn setStatusBarHidden(&self, status_bar_hidden: bool)

👎Deprecated: Use -[UIViewController prefersStatusBarHidden]

Setter for [isStatusBarHidden][Self::isStatusBarHidden].

pub unsafe fn setStatusBarHidden_withAnimation( &self, hidden: bool, animation: UIStatusBarAnimation, )

👎Deprecated: Use -[UIViewController prefersStatusBarHidden]

pub unsafe fn setKeepAliveTimeout_handler( &self, timeout: NSTimeInterval, keep_alive_handler: Option<&DynBlock<dyn Fn()>>, ) -> bool

👎Deprecated: Please use PushKit for VoIP applications instead of calling this method

Available on crate feature block2 only.

pub unsafe fn clearKeepAliveTimeout(&self)

👎Deprecated: Please use PushKit for VoIP applications instead of calling this method

Methods from Deref<Target = UIResponder>

pub unsafe fn nextResponder(&self) -> Option<Retained<UIResponder>>

pub unsafe fn canBecomeFirstResponder(&self) -> bool

pub unsafe fn becomeFirstResponder(&self) -> bool

pub unsafe fn canResignFirstResponder(&self) -> bool

pub unsafe fn resignFirstResponder(&self) -> bool

pub unsafe fn isFirstResponder(&self) -> bool

pub unsafe fn touchesBegan_withEvent( &self, touches: &NSSet<UITouch>, event: Option<&UIEvent>, )

Available on crate features UIEvent and UITouch only.

pub unsafe fn touchesMoved_withEvent( &self, touches: &NSSet<UITouch>, event: Option<&UIEvent>, )

Available on crate features UIEvent and UITouch only.

pub unsafe fn touchesEnded_withEvent( &self, touches: &NSSet<UITouch>, event: Option<&UIEvent>, )

Available on crate features UIEvent and UITouch only.

pub unsafe fn touchesCancelled_withEvent( &self, touches: &NSSet<UITouch>, event: Option<&UIEvent>, )

Available on crate features UIEvent and UITouch only.

pub unsafe fn touchesEstimatedPropertiesUpdated(&self, touches: &NSSet<UITouch>)

Available on crate feature UITouch only.

pub unsafe fn pressesBegan_withEvent( &self, presses: &NSSet<UIPress>, event: Option<&UIPressesEvent>, )

Available on crate features UIEvent and UIPress and UIPressesEvent only.

pub unsafe fn pressesChanged_withEvent( &self, presses: &NSSet<UIPress>, event: Option<&UIPressesEvent>, )

Available on crate features UIEvent and UIPress and UIPressesEvent only.

pub unsafe fn pressesEnded_withEvent( &self, presses: &NSSet<UIPress>, event: Option<&UIPressesEvent>, )

Available on crate features UIEvent and UIPress and UIPressesEvent only.

pub unsafe fn pressesCancelled_withEvent( &self, presses: &NSSet<UIPress>, event: Option<&UIPressesEvent>, )

Available on crate features UIEvent and UIPress and UIPressesEvent only.

pub unsafe fn motionBegan_withEvent( &self, motion: UIEventSubtype, event: Option<&UIEvent>, )

Available on crate feature UIEvent only.

pub unsafe fn motionEnded_withEvent( &self, motion: UIEventSubtype, event: Option<&UIEvent>, )

Available on crate feature UIEvent only.

pub unsafe fn motionCancelled_withEvent( &self, motion: UIEventSubtype, event: Option<&UIEvent>, )

Available on crate feature UIEvent only.

pub unsafe fn remoteControlReceivedWithEvent(&self, event: Option<&UIEvent>)

Available on crate feature UIEvent only.

pub unsafe fn canPerformAction_withSender( &self, action: Sel, sender: Option<&AnyObject>, ) -> bool

pub unsafe fn targetForAction_withSender( &self, action: Sel, sender: Option<&AnyObject>, ) -> Option<Retained<AnyObject>>

pub unsafe fn buildMenuWithBuilder( &self, builder: &ProtocolObject<dyn UIMenuBuilder>, )

Available on crate feature UIMenuBuilder only.

pub unsafe fn validateCommand(&self, command: &UICommand)

Available on crate features UICommand and UIMenuElement only.

pub unsafe fn undoManager(&self) -> Option<Retained<NSUndoManager>>

pub unsafe fn editingInteractionConfiguration( &self, ) -> UIEditingInteractionConfiguration

pub unsafe fn keyCommands(&self) -> Option<Retained<NSArray<UIKeyCommand>>>

Available on crate features UICommand and UIKeyCommand and UIMenuElement only.

pub unsafe fn inputView(&self) -> Option<Retained<UIView>>

Available on crate feature UIView only.

pub unsafe fn inputAccessoryView(&self) -> Option<Retained<UIView>>

Available on crate feature UIView only.

pub unsafe fn inputAssistantItem(&self) -> Retained<UITextInputAssistantItem>

Available on crate feature UITextInput only.

This method is for clients that wish to put buttons on the Shortcuts Bar, shown on top of the keyboard. You may modify the returned inputAssistantItem to add to or replace the existing items on the bar. Modifications made to the returned UITextInputAssistantItem are reflected automatically. This method should not be overridden. Goes up the responder chain.

pub unsafe fn inputViewController( &self, ) -> Option<Retained<UIInputViewController>>

Available on crate features UIInputViewController and UIViewController only.

pub unsafe fn inputAccessoryViewController( &self, ) -> Option<Retained<UIInputViewController>>

Available on crate features UIInputViewController and UIViewController only.

pub unsafe fn textInputMode(&self) -> Option<Retained<UITextInputMode>>

Available on crate feature UITextInput only.

pub unsafe fn textInputContextIdentifier(&self) -> Option<Retained<NSString>>

pub unsafe fn reloadInputViews(&self)

pub unsafe fn userActivity(&self) -> Option<Retained<NSUserActivity>>

pub unsafe fn setUserActivity(&self, user_activity: Option<&NSUserActivity>)

Setter for userActivity.

pub unsafe fn updateUserActivityState(&self, activity: &NSUserActivity)

pub unsafe fn restoreUserActivityState(&self, activity: &NSUserActivity)

pub unsafe fn captureTextFromCamera(&self, sender: Option<&AnyObject>)

pub unsafe fn activityItemsConfiguration( &self, ) -> Option<Retained<ProtocolObject<dyn UIActivityItemsConfigurationReading>>>

Available on crate features UIResponder_UIActivityItemsConfiguration and UIActivityItemsConfigurationReading only.

pub unsafe fn setActivityItemsConfiguration( &self, activity_items_configuration: Option<&ProtocolObject<dyn UIActivityItemsConfigurationReading>>, )

Available on crate features UIResponder_UIActivityItemsConfiguration and UIActivityItemsConfigurationReading only.

Setter for activityItemsConfiguration.

Methods from Deref<Target = NSObject>

pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>

pub fn class(&self) -> &'static AnyClass

Available on crate feature UIIndirectScribbleInteraction only.

Dynamically find the class of this object.

Panics

May panic if the object is invalid (which may be the case for objects returned from unavailable init/new methods).

Example

Check that an instance of NSObject has the precise class NSObject.

use objc2::ClassType;
use objc2::runtime::NSObject;

let obj = NSObject::new();
assert_eq!(obj.class(), NSObject::class());

pub unsafe fn get_ivar<T>(&self, name: &str) -> &T

where T: Encode,

👎Deprecated: this is difficult to use correctly, use Ivar::load instead.

Available on crate feature UIIndirectScribbleInteraction only.

Use Ivar::load instead.

Safety

The object must have an instance variable with the given name, and it must be of type T.

See Ivar::load_ptr for details surrounding this.

pub fn downcast_ref<T>(&self) -> Option<&T>

where T: DowncastTarget,

Available on crate feature UIIndirectScribbleInteraction only.

Attempt to downcast the object to a class of type T.

This is the reference-variant. Use Retained::downcast if you want to convert a retained object to another type.

Mutable classes

Some classes have immutable and mutable variants, such as NSString and NSMutableString.

When some Objective-C API signature says it gives you an immutable class, it generally expects you to not mutate that, even though it may technically be mutable “under the hood”.

So using this method to convert a NSString to a NSMutableString, while not unsound, is generally frowned upon unless you created the string yourself, or the API explicitly documents the string to be mutable.

See Apple’s documentation on mutability and on isKindOfClass: for more details.

Generic classes

Objective-C generics are called “lightweight generics”, and that’s because they aren’t exposed in the runtime. This makes it impossible to safely downcast to generic collections, so this is disallowed by this method.

You can, however, safely downcast to generic collections where all the type-parameters are AnyObject.

Panics

This works internally by calling isKindOfClass:. That means that the object must have the instance method of that name, and an exception will be thrown (if CoreFoundation is linked) or the process will abort if that is not the case. In the vast majority of cases, you don’t need to worry about this, since both root objects NSObject and NSProxy implement this method.

Examples

Cast an NSString back and forth from NSObject.

use objc2::rc::Retained;
use objc2_foundation::{NSObject, NSString};

let obj: Retained<NSObject> = NSString::new().into_super();
let string = obj.downcast_ref::<NSString>().unwrap();
// Or with `downcast`, if we do not need the object afterwards
let string = obj.downcast::<NSString>().unwrap();

Try (and fail) to cast an NSObject to an NSString.

use objc2_foundation::{NSObject, NSString};

let obj = NSObject::new();
assert!(obj.downcast_ref::<NSString>().is_none());

Try to cast to an array of strings.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);
// This is invalid and doesn't type check.
let arr = arr.downcast_ref::<NSArray<NSString>>();

This fails to compile, since it would require enumerating over the array to ensure that each element is of the desired type, which is a performance pitfall.

Downcast when processing each element instead.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);

for elem in arr {
    if let Some(data) = elem.downcast_ref::<NSString>() {
        // handle `data`
    }
}

Trait Implementations

impl AsRef<AnyObject> for UIApplication

fn as_ref(&self) -> &AnyObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<NSObject> for UIApplication

fn as_ref(&self) -> &NSObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<UIApplication> for UIApplication

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<UIResponder> for UIApplication

fn as_ref(&self) -> &UIResponder

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<AnyObject> for UIApplication

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for UIApplication

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl Borrow<UIResponder> for UIApplication

fn borrow(&self) -> &UIResponder

Immutably borrows from an owned value.

impl ClassType for UIApplication

const NAME: &'static str = "UIApplication"

The name of the Objective-C class that this type represents.

type Super = UIResponder

The superclass of this class.

type ThreadKind = dyn MainThreadOnly

Whether the type can be used from any thread, or from only the main thread.

fn class() -> &'static AnyClass

Get a reference to the Objective-C class that this type represents.

fn as_super(&self) -> &Self::Super

Get an immutable reference to the superclass.

impl Debug for UIApplication

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for UIApplication

type Target = UIResponder

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Hash for UIApplication

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Message for UIApplication

fn retain(&self) -> Retained<Self>

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for UIApplication

fn isEqual(&self, other: Option<&AnyObject>) -> bool

where Self: Sized + Message,

Check whether the object is equal to an arbitrary other object.

fn hash(&self) -> usize

where Self: Sized + Message,

An integer that can be used as a table address in a hash table structure.

fn isKindOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of the class, or one of its subclasses.

fn is_kind_of<T>(&self) -> bool

where T: ClassType, Self: Sized + Message,

👎Deprecated: use isKindOfClass directly, or cast your objects with AnyObject::downcast_ref

Check if the object is an instance of the class type, or one of its subclasses.

fn isMemberOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of a specific class, without checking subclasses.

fn respondsToSelector(&self, aSelector: Sel) -> bool

where Self: Sized + Message,

Check whether the object implements or inherits a method with the given selector.

fn conformsToProtocol(&self, aProtocol: &AnyProtocol) -> bool

where Self: Sized + Message,

Check whether the object conforms to a given protocol.

fn description(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object.

fn debugDescription(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object to use when debugging.

fn isProxy(&self) -> bool

where Self: Sized + Message,

Check whether the receiver is a subclass of the NSProxy root class instead of the usual NSObject.

fn retainCount(&self) -> usize

where Self: Sized + Message,

The reference count of the object.

impl PartialEq for UIApplication

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RefEncode for UIApplication

const ENCODING_REF: Encoding = <UIResponder as ::objc2::RefEncode>::ENCODING_REF

The Objective-C type-encoding for a reference of this type.

impl UIResponderStandardEditActions for UIApplication

unsafe fn cut(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn copy(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn paste(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn pasteAndMatchStyle(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn pasteAndGo(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn pasteAndSearch(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn select(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn selectAll(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn delete(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn makeTextWritingDirectionLeftToRight(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn makeTextWritingDirectionRightToLeft(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn toggleBoldface(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn toggleItalics(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn toggleUnderline(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn increaseSize(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn decreaseSize(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn find(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn findAndReplace(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn findNext(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn findPrevious(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn useSelectionForFind(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn updateTextAttributesWithConversionHandler( &self, conversion_handler: UITextAttributesConversionHandler, )

where Self: Sized + Message,

Available on crate features UIResponder and block2 only.

unsafe fn print(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn rename(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn duplicate(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn move(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn export(&self, sender: Option<&AnyObject>)

where Self: Sized + Message,

Available on crate feature UIResponder only.

unsafe fn showWritingTools(&self, sender: &AnyObject)

where Self: Sized + Message,

Available on crate feature UIResponder only.

impl DowncastTarget for UIApplication

impl Eq for UIApplication