Вы получаете доступ к закрытым внутренним данным UIActivityViewController.Невозможно сказать, для чего используется этот ивар и при каких условиях его безопасно устанавливать.setValue(_:forKey:) - это динамический метод, который позволит вам получить доступ к произвольным внутренним объектам, но это не значит, что вы должны это делать.
В исследовательских целях вы можете использовать такие инструменты, как class-dump или Бункер для обратного инжиниринга класса, или вы можете запросить его во время выполнения следующим образом:
let cls = UIActivityViewController.self
var count: UInt32 = 0
let ivars = class_copyIvarList(cls, &count)!
for i in 0..<count {
let ivar = ivars[Int(i)]
let name = ivar_getName(ivar)!
print(String(cString: name))
}
print("---")
let properties = class_copyPropertyList(cls, &count)!
for i in 0..<count {
let property = properties[Int(i)]
let name = property_getName(property)
print(String(cString: name))
}
Это выведет список всех ivars и свойств, большинство из которых setValue(_:forKey:) может получить доступ по умолчанию для текущего класса.Он не будет включать свойства из суперкласса или не принадлежащие ему свойства.Вы должны были бы глубже для этого.(Но опять же, это не то, как setValue(_:forKey:) используется. Вы используете его, читая документацию для класса, а не просто осматривайтесь.
Используя class-dump, вы увидите следующее для UIActivityViewController:
class-dump -C '^UIActivityViewController$' /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore
///// ... HEADER OMITTED ....
//
// File: /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore
// UUID: 2DB941E0-513E-3750-9278-C8AFB85CB3C0
//
// Arch: x86_64
// Current version: 61000.0.0
// Compatibility version: 1.0.0
// Source version: 3698.29.8.0.0
//
// Objective-C Garbage Collection: Unsupported
//
@interface UIActivityViewController : UIViewController <UIAlertControllerContaining, UIAlertControllerVisualStyleProviding, UIViewControllerRestoration, UIActionSheetPresentationControllerDelegate, _UIActivityHelperDelegate, _UIShareExtensionHost>
{
_Bool _waitingForInitialShareServicePreferredContentSize;
_Bool _shareServicePreferredContentSizeIsValid;
_Bool __viewServiceBeganConnecting;
_Bool _dismissalDetectionOfViewControllerForSelectedActivityShouldAutoCancel;
_Bool _willDismissActivityViewController;
_Bool _performActivityForStateRestoration;
_Bool _shouldMatchOnlyUserElectedExtensions;
_Bool _hasPerformedInitialPresentation;
_Bool _isPerformingPresentation;
_Bool _allowsEmbedding;
_Bool _showKeyboardAutomatically;
_Bool _sourceIsManaged;
CDUnknownBlockType _completionHandler;
CDUnknownBlockType _completionWithItemsHandler;
NSArray *_excludedActivityTypes;
_UIShareExtensionRemoteViewController *_remoteContentViewController;
NSExtension *_shareExtension;
id <NSCopying> _extensionRequestIdentifier;
id <_UIShareExtensionService> _shareExtensionService;
UISUIActivityViewControllerConfiguration *_activityViewControllerConfiguration;
_UIActivityGroupListViewController *_placeholderViewController;
NSArray *_activityItems;
NSArray *_applicationActivities;
NSMutableDictionary *_activitiesByUUID;
_UIActivityHelper *_activityHelper;
long long _originalPopoverBackgroundStyle;
Class _originalPopoverBackgroundViewClass;
CDUnknownBlockType __popoverDismissalAction;
CDUnknownBlockType _activityPresentationCompletionHandler;
UIAlertController *_activityAlertController;
_UIAlertControllerShimPresenter *_activityAlertControllerShimPresenter;
UIAlertAction *_activityAlertCancelAction;
NSArray *_activityItemProviderOperations;
NSOperationQueue *_activityItemProviderOperationQueue;
long long _totalProviderCount;
long long _completedProviderCount;
unsigned long long _backgroundTaskIdentifier;
NSString *_subject;
unsigned long long _clientAttemptedInitialPresentationOrEmbeddingTimestamp;
unsigned long long _beginPerformingActivityTimestamp;
unsigned long long _viewWillAppearTimestamp;
unsigned long long _readyToInteractTimestamp;
NSArray *_activityTypesToCreateInShareService;
NSArray *_resolvedActivityItemsForCurrentActivity;
CDUnknownBlockType _shareSheetReadyToInteractHandler;
CDUnknownBlockType _preCompletionHandler;
NSArray *_includedActivityTypes;
long long _excludedActivityCategories;
NSArray *_activityTypeOrder;
UIActivity *_activity;
UIViewController *_activityViewController;
id <UIActivityViewControllerDelegate> _airDropDelegate;
}
+ (id)viewControllerWithRestorationIdentifierPath:(id)arg1 coder:(id)arg2;
+ (double)_asyncPresentationTimeout;
+ (_Bool)_popoverPresentationUsesModernPresentation;
+ (_Bool)_usesActionSheetPresentationController;
@property(nonatomic) __weak id <UIActivityViewControllerDelegate> airDropDelegate; // @synthesize airDropDelegate=_airDropDelegate;
@property(retain, nonatomic) UIViewController *activityViewController; // @synthesize activityViewController=_activityViewController;
@property(retain, nonatomic) UIActivity *activity; // @synthesize activity=_activity;
@property(nonatomic) _Bool sourceIsManaged; // @synthesize sourceIsManaged=_sourceIsManaged;
@property(nonatomic) _Bool showKeyboardAutomatically; // @synthesize showKeyboardAutomatically=_showKeyboardAutomatically;
@property(nonatomic) _Bool allowsEmbedding; // @synthesize allowsEmbedding=_allowsEmbedding;
@property(copy, nonatomic) NSArray *activityTypeOrder; // @synthesize activityTypeOrder=_activityTypeOrder;
@property(nonatomic) long long excludedActivityCategories; // @synthesize excludedActivityCategories=_excludedActivityCategories;
@property(copy, nonatomic) NSArray *includedActivityTypes; // @synthesize includedActivityTypes=_includedActivityTypes;
@property(copy, nonatomic) CDUnknownBlockType preCompletionHandler; // @synthesize preCompletionHandler=_preCompletionHandler;
@property(copy, nonatomic, getter=_shareSheetReadyToInteractHandler, setter=_setShareSheetReadyToInteractHandler:) CDUnknownBlockType shareSheetReadyToInteractHandler; // @synthesize shareSheetReadyToInteractHandler=_shareSheetReadyToInteractHandler;
@property(readonly, nonatomic) NSArray *resolvedActivityItemsForCurrentActivity; // @synthesize resolvedActivityItemsForCurrentActivity=_resolvedActivityItemsForCurrentActivity;
@property(retain, nonatomic) NSArray *activityTypesToCreateInShareService; // @synthesize activityTypesToCreateInShareService=_activityTypesToCreateInShareService;
@property(nonatomic, getter=_readyToInteractTimestamp, setter=_setReadyToInteractTimestamp:) unsigned long long readyToInteractTimestamp; // @synthesize readyToInteractTimestamp=_readyToInteractTimestamp;
@property(nonatomic, getter=_viewWillAppearTimestamp, setter=_setViewWillAppearTimestamp:) unsigned long long viewWillAppearTimestamp; // @synthesize viewWillAppearTimestamp=_viewWillAppearTimestamp;
@property(nonatomic, getter=_beginPerformingActivityTimestamp, setter=_setBeginPerformingActivityTimestamp:) unsigned long long beginPerformingActivityTimestamp; // @synthesize beginPerformingActivityTimestamp=_beginPerformingActivityTimestamp;
@property(nonatomic, getter=_clientAttemptedInitialPresentationOrEmbeddingTimestamp, setter=_setClientAttemptedInitialPresentationOrEmbeddingTimestamp:) unsigned long long clientAttemptedInitialPresentationOrEmbeddingTimestamp; // @synthesize clientAttemptedInitialPresentationOrEmbeddingTimestamp=_clientAttemptedInitialPresentationOrEmbeddingTimestamp;
@property(nonatomic, getter=_isPerformingPresentation, setter=_setIsPerformingPresentation:) _Bool isPerformingPresentation; // @synthesize isPerformingPresentation=_isPerformingPresentation;
@property(nonatomic, getter=_hasPerformedInitialPresentation, setter=_setHasPerformedInitialPresentation:) _Bool hasPerformedInitialPresentation; // @synthesize hasPerformedInitialPresentation=_hasPerformedInitialPresentation;
@property(nonatomic) _Bool shouldMatchOnlyUserElectedExtensions; // @synthesize shouldMatchOnlyUserElectedExtensions=_shouldMatchOnlyUserElectedExtensions;
@property(nonatomic) _Bool performActivityForStateRestoration; // @synthesize performActivityForStateRestoration=_performActivityForStateRestoration;
@property(copy, nonatomic) NSString *subject; // @synthesize subject=_subject;
@property(nonatomic) unsigned long long backgroundTaskIdentifier; // @synthesize backgroundTaskIdentifier=_backgroundTaskIdentifier;
@property(nonatomic) long long completedProviderCount; // @synthesize completedProviderCount=_completedProviderCount;
@property(nonatomic) long long totalProviderCount; // @synthesize totalProviderCount=_totalProviderCount;
@property(retain, nonatomic) NSOperationQueue *activityItemProviderOperationQueue; // @synthesize activityItemProviderOperationQueue=_activityItemProviderOperationQueue;
@property(retain, nonatomic) NSArray *activityItemProviderOperations; // @synthesize activityItemProviderOperations=_activityItemProviderOperations;
@property(retain, nonatomic) UIAlertAction *activityAlertCancelAction; // @synthesize activityAlertCancelAction=_activityAlertCancelAction;
@property(retain, nonatomic) _UIAlertControllerShimPresenter *activityAlertControllerShimPresenter; // @synthesize activityAlertControllerShimPresenter=_activityAlertControllerShimPresenter;
@property(retain, nonatomic) UIAlertController *activityAlertController; // @synthesize activityAlertController=_activityAlertController;
@property(copy, nonatomic, getter=_activityPresentationCompletionHandler, setter=_setActivityPresentationCompletionHandler:) CDUnknownBlockType activityPresentationCompletionHandler; // @synthesize activityPresentationCompletionHandler=_activityPresentationCompletionHandler;
@property(nonatomic) _Bool willDismissActivityViewController; // @synthesize willDismissActivityViewController=_willDismissActivityViewController;
@property(nonatomic) _Bool dismissalDetectionOfViewControllerForSelectedActivityShouldAutoCancel; // @synthesize dismissalDetectionOfViewControllerForSelectedActivityShouldAutoCancel=_dismissalDetectionOfViewControllerForSelectedActivityShouldAutoCancel;
@property(copy, nonatomic) CDUnknownBlockType _popoverDismissalAction; // @synthesize _popoverDismissalAction=__popoverDismissalAction;
@property(retain, nonatomic) Class originalPopoverBackgroundViewClass; // @synthesize originalPopoverBackgroundViewClass=_originalPopoverBackgroundViewClass;
@property(nonatomic) long long originalPopoverBackgroundStyle; // @synthesize originalPopoverBackgroundStyle=_originalPopoverBackgroundStyle;
@property(retain, nonatomic) _UIActivityHelper *activityHelper; // @synthesize activityHelper=_activityHelper;
@property(retain, nonatomic) NSMutableDictionary *activitiesByUUID; // @synthesize activitiesByUUID=_activitiesByUUID;
@property(copy, nonatomic) NSArray *applicationActivities; // @synthesize applicationActivities=_applicationActivities;
@property(copy, nonatomic) NSArray *activityItems; // @synthesize activityItems=_activityItems;
@property(retain, nonatomic, getter=_placeholderViewController, setter=_setPlaceholderViewController:) _UIActivityGroupListViewController *placeholderViewController; // @synthesize placeholderViewController=_placeholderViewController;
@property(nonatomic) _Bool _viewServiceBeganConnecting; // @synthesize _viewServiceBeganConnecting=__viewServiceBeganConnecting;
@property(nonatomic) _Bool shareServicePreferredContentSizeIsValid; // @synthesize shareServicePreferredContentSizeIsValid=_shareServicePreferredContentSizeIsValid;
@property(nonatomic) _Bool waitingForInitialShareServicePreferredContentSize; // @synthesize waitingForInitialShareServicePreferredContentSize=_waitingForInitialShareServicePreferredContentSize;
@property(retain, nonatomic) UISUIActivityViewControllerConfiguration *activityViewControllerConfiguration; // @synthesize activityViewControllerConfiguration=_activityViewControllerConfiguration;
@property(retain, nonatomic) id <_UIShareExtensionService> shareExtensionService; // @synthesize shareExtensionService=_shareExtensionService;
@property(copy, nonatomic) id <NSCopying> extensionRequestIdentifier; // @synthesize extensionRequestIdentifier=_extensionRequestIdentifier;
@property(retain, nonatomic) NSExtension *shareExtension; // @synthesize shareExtension=_shareExtension;
@property(retain, nonatomic) _UIShareExtensionRemoteViewController *remoteContentViewController; // @synthesize remoteContentViewController=_remoteContentViewController;
@property(copy, nonatomic) NSArray *excludedActivityTypes; // @synthesize excludedActivityTypes=_excludedActivityTypes;
@property(copy, nonatomic) CDUnknownBlockType completionWithItemsHandler; // @synthesize completionWithItemsHandler=_completionWithItemsHandler;
@property(copy, nonatomic) CDUnknownBlockType completionHandler; // @synthesize completionHandler=_completionHandler;
- (void).cxx_destruct;
- (void)shareExtensionServiceAirDropActivityDidSuccessfullyCompleteTransfer;
- (void)shareExtensionServiceAirDropActivityDidSuccessfullyStartTransfer;
- (void)_willPerformInServiceActivityType:(id)arg1 activitySpecificMetadata:(id)arg2;
- (void)shareExtensionServiceRequestPerformActivityInHostForExtensionActivityWithBundleIdentifier:(id)arg1;
- (void)shareExtensionServiceRequestPerformActivityInHostForActivityUUID:(id)arg1;
- (void)shareExtensionServiceDidFinishPerformingInServiceActivityWithUUID:(id)arg1 responseData:(id)arg2;
- (void)shareExtensionServiceWillPerformInServiceActivityWithDataRequest:(id)arg1 dismissPresentation:(_Bool)arg2 completion:(CDUnknownBlockType)arg3;
- (void)shareExtensionServiceDisableSheetAvoidsKeyboardUntilContentSizeUpdate;
- (void)shareExtensionServiceChangeSheetDismissButtonHidden:(_Bool)arg1;
- (void)shareExtensionServiceChangeSheetDismissButtonTitle:(id)arg1;
- (void)_shareExtensionServicePreferredContentSizeUpdated:(struct CGSize)arg1;
- (_Bool)_shouldShowSystemActivityType:(id)arg1;
- (_Bool)activityHelper:(id)arg1 matchingWithContext:(id)arg2 shouldIncludeSystemActivityType:(id)arg3;
- (id)_configurationForActivity:(id)arg1;
- (id)_activityConfigurationsForActivities:(id)arg1;
- (id)_newShareUIConfigurationWithMatchingResults:(id)arg1;
- (id)_newShareUIConfigurationForCurrentState;
- (void)_loadActivityViewControllerConfiguration;
- (void)_preheatActivityViewControllerConfiguration;
- (void)_insertIntoActivitiesByUUID:(id)arg1;
- (void)_removeFromActivitiesByUUID:(id)arg1;
- (id)_activityWithActivityUUID:(id)arg1;
- (void)decodeRestorableStateWithCoder:(id)arg1;
- (void)encodeRestorableStateWithCoder:(id)arg1;
- (void)actionSheetPresentationControllerDidDismissActionSheet:(id)arg1;
- (id)visualStyleForAlertControllerStyle:(long long)arg1 traitCollection:(id)arg2 descriptor:(id)arg3;
- (void)presentViewController:(id)arg1 animated:(_Bool)arg2 completion:(CDUnknownBlockType)arg3;
- (void)_cancel;
- (void)_didResignContentViewControllerOfPopover:(id)arg1;
- (void)_setPopoverController:(id)arg1;
- (void)observeValueForKeyPath:(id)arg1 ofObject:(id)arg2 change:(id)arg3 context:(void *)arg4;
- (void)_changeActionSheetAvoidsKeyboardDisabledUntilNextUpdatePreferredContentSize:(_Bool)arg1;
- (void)_changeActionPresentationDismissButtonHidden:(_Bool)arg1;
- (void)_changeActionPresentationDismissButtonTitle:(id)arg1;
- (void)_endDismissalDetectionOfViewControllerForSelectedActivityShouldAutoCancel;
- (void)_presentationControllerDismissalTransitionDidEndNotification:(id)arg1;
- (void)_beginDismissalDetectionOfViewControllerForSelectedActivityShouldAutoCancel;
- (void)_endInProgressActivityExecutionForcedStrongReference;
- (void)_beginInProgressActivityExecutionForcedStrongReference;
- (_Bool)_queueBackgroundOperationsForActivityItems:(id)arg1 activityBeingPerformed:(id)arg2;
- (void)_performActivity:(id)arg1;
- (_Bool)_shouldExecuteItemOperation:(id)arg1 forActivity:(id)arg2;
- (void)_performActivityOfType:(id)arg1 executionEnvironment:(long long)arg2;
- (void)_prepareActivity:(id)arg1 completion:(CDUnknownBlockType)arg2;
- (void)_prepareActivity:(id)arg1;
- (id)_titleForActivity:(id)arg1;
- (void)_resetAfterActivity:(_Bool)arg1;
- (void)_executeActivity;
- (void)_cleanupActivityWithSuccess:(_Bool)arg1;
- (void)_cleanupActivityWithSuccess:(_Bool)arg1 items:(id)arg2 error:(id)arg3;
- (void)_emitInteractionTelemetry:(_Bool)arg1 error:(id)arg2;
- (void)_clearActivity;
- (void)_performDismissWithCompletionHandler:(CDUnknownBlockType)arg1;
- (void)_updateSourceIsManagedForURLs;
- (_Bool)shouldAutorotateToInterfaceOrientation:(long long)arg1;
- (void)viewWillTransitionToSize:(struct CGSize)arg1 withTransitionCoordinator:(id)arg2;
- (void)dismissViewControllerAnimated:(_Bool)arg1 completion:(CDUnknownBlockType)arg2;
- (void)setModalPresentationStyle:(long long)arg1;
- (id)_presentationControllerForPresentedController:(id)arg1 presentingController:(id)arg2 sourceController:(id)arg3;
- (_Bool)_requiresCustomPresentationController;
- (void)_updatePlaceholderPreferredContentSize;
- (void)preferredContentSizeDidChangeForChildContentContainer:(id)arg1;
- (void)viewSafeAreaInsetsDidChange;
- (void)viewDidLayoutSubviews;
- (void)__viewControllerWillBePresented:(_Bool)arg1;
- (void)viewWillDisappear:(_Bool)arg1;
- (void)viewDidAppear:(_Bool)arg1;
- (void)viewWillAppear:(_Bool)arg1;
- (double)_displayHeight;
- (void)_presentationOrEmbeddingDidBegin:(_Bool)arg1;
- (void)_createAndInstallPlaceholderViewControllerIfNeeded;
- (_Bool)_isActionRowExcluded;
- (_Bool)_isSharingRowExcluded;
- (_Bool)_isAirDropExcludedWithActivityItemValues:(id)arg1;
- (_Bool)_shouldIncludeTagsUIPlaceholderWithActivityItemValues:(id)arg1;
- (id)_containedAlertController;
- (void)_shareSheetReadyToInteractAfterCACommit:(_Bool)arg1;
- (void)_removePlaceholderViewControllerIfNeeded;
- (void)_installViewController:(id)arg1;
- (void)_embedRemoteContentViewControllerAndPerformAfterCompletingFencedCommit:(CDUnknownBlockType)arg1;
- (void)viewDidLoad;
- (void)_updateActivityViewControllerConfiguration;
- (void)_updateActivityItems:(id)arg1;
- (id)_newActivityMatchingContext;
- (id)_availableActivities;
- (id)_activityItemValues;
- (id)_securityScopedURLsForMatching;
- (id)_activityItemURLValuesForMatching;
- (id)_placeholderActivityItemValues;
- (void)dealloc;
- (void)_setupLegacyAlertPresentationControllers;
- (void)_preheatActivitiesIfNeeded;
- (void)_shareServiceFinishedInitialPreferredContentSizeUpdate;
- (void)_sendInitialShareServiceConfigurationAndUpdatePreferredContentSize;
- (void)_retryRemoteViewServiceConnectionIfPossibleWithPriming:(_Bool)arg1 previousAttempts:(long long)arg2;
- (void)_connectToRemoteViewServiceOnceWithPriming:(_Bool)arg1 previousAttempts:(long long)arg2;
- (void)_primeExtensionDiscovery;
- (void)_preloadInitialConfigurationLocallyIfNeeded;
- (id)initWithActivityItems:(id)arg1 applicationActivities:(id)arg2;
- (id)initWithCoder:(id)arg1;
- (id)initWithNibName:(id)arg1 bundle:(id)arg2;
- (id)init;
@property(copy, nonatomic) CDUnknownBlockType dismissCompletionHandler;
// Remaining properties
@property(readonly, copy) NSString *debugDescription;
@property(readonly, copy) NSString *description;
@property(readonly) unsigned long long hash;
@property(readonly) Class superclass;
@end
Но опять же, это только для исследования. Вы никогда не должны полагаться на эту информацию для производственного кода. (Например, версия UIKitCore в / System / iOSSupport / System / Library /PrivateFrameworks / имеет меньший список ivars, который не включает subject, так что это может даже не работать на всех платформах UIKit.)
Примечание, не связанное с: фактическое имя свойства subject, а не Subject. Вам это сходит с рук, потому что setValue(_:forKey:) автоматически вводит первую букву заглавными буквами и создает setSubject:. Подробнее о том, как это работает, см. В Руководстве по программированию Key-Value Coding . В общем, KVCобычно не используется непосредственно в Swift, и setValue(_:forKey:) и другие методы KVC, как правило, следует избегать в Swift, если вы не знаете, что делаете. Они не являются типобезопасными.