I’m using UISheetPresentationController with a UIViewController. While the sheet is being resized I’d like to position certain subviews a certain way during the resizing event. For example I may hide some subviews on a smaller detent and unhide them on a larger detent. But while the sheet is being resized in between the small and large detent I’d like to have some subviews placed at certain locations of the view hierarchy. As far as I can tell the only way to do this is with unreliable hard coded values: -(void)viewDidLayoutSubviews { [super viewDidLayoutSubviews]; CGFloat currentHeight = self.view.bounds.size.height; if (currentHeight <= mediumDetent) { [self doLayoutForMediumDetent]; } else if (currentHeight >= fullSizeDetent) { [self doLayoutForFullSizedDetent]; } else { [self doLayoutInBetweenFullAndMediumSheetWithCurrentSize:currentHeight]; } } I don't really know for sure the height of the detents. I'm using estimates so this layout code is fragile. For the medium detent the documentation states that it is "A system detent for a sheet that is approximately half the height of the screen, and is inactive in compact height." but on certain devices the medium detent height is not exactly 1/2 the screen height. Ideally it would be nice to have API like this: -(void)viewDidLayoutSubviews { [super viewDidLayoutSubviews]; CGFloat mediumHeight = [self.sheetPresentationController resolvedHeightForDetentWithIdentiier:someID withTraitCollection:self.traitCollection]; CGFloat fullHeight = [self.sheetPresentationController resolvedHeightForDetentWithIdentiier:FullSizeID withTraitCollection:self.traitCollection]; if (self.sheetPresentationController.isInLiveResize) { //do whatever during live resize } else { //do whatever at the current size } } Is there currently a better way to achieve what I'm after?

So I'm using a custom presentation controller which requires me to specify a transitioningDelegate on the view controller before presenting it like this: vcToPresent.modalPresentationStyle = UIModalPresentationCustom; vcToPresent.transitioningDelegate = transitionDelegate; Now I want to enforce a particular view controller to always use my custom presentation controller. Unfortunately I cannot just override the presentationController getter and return my own custom class; I have to make a transitioning delegate and an additional animator (and my custom presentation controller can animate alongside it). To have a view controller use my own presentation controller I have to do this: -(void)presentCustomVC { MyViewController *vcToPresent = [MyViewController makeViewController]; MyTransitioningDelegate *transitionDelegate = [[MyTransitioningDelegate alloc]init]; vcToPresent.modalPresentationStyle = UIModalPresentationCustom; vcToPresent.transitioningDelegate = transitionDelegate; [self presentViewController:vcToPresent animated:YES completion:nil]; } So I have to copy this transitioningDelegate set up code in every view controller that presents MyViewController. I can make the API look a little better by creating a factory method in MyViewController like this: +(MyViewController*)makeViewController { UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Storyboard" bundle:nil]; MyViewController *theVC = [storyboard instantiateInitialViewController]; MyTransitioningDelegate *transDelegate = [[MyTransitioningDelegate alloc]init]; theVC.modalPresentationStyle = UIModalPresentationCustom; theVC.transitioningDelegate = transDelegate; return theVC; } The problem with that is the transitioningDelegate gets deallocated right away (before the view controller can be presented). The transitioningDelegate property on UIViewController is weak for some reason. Shouldn't the transitioningDelegate property be declared strong? My custom transitioningDelegate has no strong reference to the presented view controller? If I add a redundant property to MyViewController like this: @property (nonatomic,strong) MyTransitioningDelegate *strongTransDelegate; And then do this: theVC.modalPresentationStyle = UIModalPresentationCustom; theVC.transitioningDelegate = transDelegate; theVC.strongTransDelegate = transitionDelegate; All seems to work well. When the view controller is dismissed the transitioning delegate is deallocated. However I'm assuming the transitioningDelegate property on UIViewController was declared as weak for a reason? I don't want to accidentally create a retain cycle in some unforeseen circumstance. Documentation makes no mention on who should be the "owner" of the transitioning delegate?

I have a custom pop animation is use with UINavigationController. I provide this via the delegate method - -(nullable id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController*)navigationController animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController*)fromVC toViewController:(UIViewController*)toVC And it works except when I push the view controller initially from UISearchController's .searchResultsController. This issue is that when I push on the navigation stack when the UISearchResultsController is displaying the searchResultsController, when I pop back the UIViewControllerContextTransitioning passed to my animator doesn't provide values to account for the search controller displayed over the main view controller and the custom animation doesn't work. Is there a good way to handle this? Thanks in advance.

Is there a way to block certain embedded inline javascript elements using WKContentRuleList? For example <script> evilJavascriptHere </script> The documentation states that you can specify a url-filter but what about inline scripts?

It appears a lot of useful WWDC session videos from previous years have been scrubbed from the developer.apple.com? I cannot find the WWDC session "Customized Loading in WKWebView" from 2017 in the Developer app nor on the developer website. There are lots of other videos that would be useful to watch, even from years ago. Am I just not looking in the right place?

I need to prepare an object when the user navigates to a new page in WKWebView and refresh UI. I run a WKUserScript on behalf of the user to do this. I'm using the readystatechange event listener to detect initial page load. I'm also listening to the visibilitychange event to refresh UI if the DOM is already loaded on a "Go back" or "Go Forward" action. document.addEventListener('visibilitychange', () => { //do whatever if the DOM is already loaded and if we are visible. }); document.addEventListener('readystatechange', (event) => { //do whatever when page is loaded }); On certain websites however I noticed that neither of these events are being fired when I navigate -goForward: and -goBack: I'm not sure why. My WKUserScript is in WKContentWorld.defaultClientWorld so it shouldn't be interfering with the javascript of the page. Is there another JS event I'm missing? I could pick up the changed URL on the native code side but it would be nice to keep this all contained within the WKUserScript as this UI is for the "webview" and the native code shouldn't have to be bothered with having to patch in the additional glue. Is there another DOM event I need to listen to? I tried listening to window's pageshow but that didn't work. Also experimented a bit with the window's popstate event but no luck.

I see in the documentation that it is possible to hide elements on a page using a CSS selector by setting the action type to css-display-none and then providing a selector. But this is kind of limited. You have to know every selector for every style sheet ahead of time. It's possible to block loading of a style sheet using a block rule. "trigger" : { "load-type" : [ "third-party" ], "url-filter" : "REGEX_FOR_STYLESHEET_OF_KNOWN_NASTY_CONTENT_PROVIDER", "resource-type" : [ "style-sheet" ], "url-filter-is-case-sensitive" : true }, "action" : { "type" : "block" } Is is my understanding that the above rule will block loading of a stylesheet that matches the url-filter but all elements will still be displayed by WKWebView using the default style provided by the browser. Am I misunderstanding? Ideally I'd like to be able to set display:none; for every selector in the evil style sheet. I of course can look at the style sheet and make css-display-none rules for every selector manually but that's pretty much impossible to maintain for rule lists with thousands of entires and will break when the author of the nasty stylesheet makes any changes. Is there a way to accomplish what I'm after using WKContentRuleList?

I see WKContentRuleListStore saves compile lists by identifier. It's nice that I don't have to recompile the WKContentRuleListStore on every app launch but is there ever an event where the system discards compiled lists (other than me calling -removeContentRuleListForIdentifier:completionHandler:)? The reason I ask is should I be writing a version number with my compiled list? If I change the JSON code on an app update do I need to manually remove compiled lists after an app update before recompiling the new JSON?

I have a horizontal section in my compositional layout with three items. 0 ---- 1 ----2 When scrolling toward the center I want the scrolling to snap the item at index 1 to the center of the screen. However I can't figure out how to precisely control horizontal scrolling with compositional layout (it doesn't seem possible to control the contentOffset of horizontal scrolling). When I enable paging using UICollectionLayoutSectionOrthogonalScrollingBehaviorPaging the page size assumes full device width and paging works for the item at index 0 or 2 but then the item at index 1 can never be displayed fully on screen (only one half of its width can be shown at a given time). I tried adding leading and trailing space to the group but that didn't work. When I try the UICollectionLayoutSectionOrthogonalScrollingBehaviorGroupPaging the section is displayed with the item at index 1 centered but scrolling doesn't work. I think what I'm looking for is UICollectionLayoutSectionOrthogonalScrollingBehaviorGroupPaging but at the item level or to be able to adjust the contentOffset on the scroll view at the end of dragging. Is there any way I can programmatically access the scroll view being using for horizontal scrolling? I see in the visibleItemsInvalidationHandler I'm able to get the content offset but I'm not able to change it to support snapping.

I have a Mac Catalyst app. When using "Live Previews" in Xcode 15 for a view controller of mine the live preview renders at a gigantic size in the Preview. This view controller is only ever presented as a "sheet" on Mac at a fixed size so ideally I'd like to be able to specify the "window size" for the preview environment. Is there a way to do this? Thanks in advance.

I have a UIViewController subclass I'm using in Mac Catalyst. This view controller is only ever presented as a sheet. When I try to make a live preview for it the preview is displayed a gigantic size (not the sheet's actual size at runtime). I made a separate thread about this: https://developer.apple.com/forums/thread/738641 In order to be able to preview the view controller for Mac Catalyst at the desired size I figured I'd present it on another view controller. #Preview { let wrapperVC = WrapperViewController() return wrapperVC } //In WrapperViewController override func viewDidAppear(_ animated: Bool) { super.viewDidAppear(animated) if (firstViewDidAppear) { firstViewDidAppear = false view.backgroundColor = UIColor.yellow let realVC = ActualVCIWantToPreview() realVC.modalPresentationStyle = .formSheet present(realVC, animated: false); } } But that's not working. However if I change the device from Mac to iPad it does work so it appears modal presentations aren't working for Live Previews on Mac Catalyst (unless I'm doing something wrong but Xcode is reporting no errors it just isn't showing my presented view controller).

New in iOS 17 is NSCollectionLayoutDimension uniformAcrossSiblingsWithEstimate: method. I have two collection view items positioned side by side in a a grid and would like to use this feature to give them equal heights. I configure the items like so: -Each "box" in grid is made up of two vertical items -Title item configured with a fractional width of 0.5 and a estimated height. -Description item configured with a fractional width of 0.5 and a estimated height. Then the "box" wraps both the "title item" and a description item vertically NSCollectionLayoutSize *boxSize = [NSCollectionLayoutSize sizeWithFractionalWidth:0.5 estHeightUniformAcrossSiblings:estTitleHeight+estDescriptionheight]]; NSCollectionLayoutGroup *boxGroup = [NSCollectionLayoutGroup verticalGroupWithLayoutSize:boxSize subitems:@[titleItem,descriptionItem]]; //Repeat the box twice to make a side by side grid. //entireRowSize is fractional width of 1.0 and estimated height (not uniform across siblings). NSCollectionLayoutGroup *sideBySideGroup = [NSCollectionLayoutGroup horizontalGroupWithLayoutSize:entireRowSize repeatingSubitem:boxGroup count:2]; But at runtime the grids do not have equal heights. It looks exactly the same as it was on iOS 16. Am I doing something wrong? Thanks in advance.

I have a customizable NSToolbar (using in a Mac Catalyst app "optimized for Mac"). When I right click and choose "Customize toolbar" I get the following error: Conflicting constraints detected: ( "<NSLayoutConstraint:0x6000014a24e0 NSToolbarItemGroupView:0x13de568c0.width <= 88.5 (active)>", "<NSAutoresizingMaskLayoutConstraint:0x6000014f5f90 h=--& v=--& NSToolbarItemGroupView:0x13de568c0.width == 89 (active)>" ). Will attempt to recover by breaking <NSLayoutConstraint:0x6000014a24e0 NSToolbarItemGroupView:0x13de568c0.width <= 88.5 (active)>. Unable to simultaneously satisfy constraints: ( "<NSLayoutConstraint:0x6000014a24e0 NSToolbarItemGroupView:0x13de568c0.width <= 88.5 (active)>", "<NSAutoresizingMaskLayoutConstraint:0x6000014f5f90 h=--& v=--& NSToolbarItemGroupView:0x13de568c0.width == 89 (active)>" ) Will attempt to recover by breaking constraint <NSLayoutConstraint:0x6000014a24e0 NSToolbarItemGroupView:0x13de568c0.width <= 88.5 (active)> Set the NSUserDefault >NSConstraintBasedLayoutVisualizeMutuallyExclusiveConstraints to YES to have ->[NSWindow visualizeConstraints:] automatically called when this happens. And/or, set a symbolic breakpoint on LAYOUT_CONSTRAINTS_NOT_SATISFIABLE to catch this in the debugger.

I have a Mac Catalyst app configured like so: The root view controller on the window is a tripe split UISplitViewController. The secondary view controller in the Split View controller is a view controller that uses WKWebView. Load a website in the WKWebview that has a video. Expand the video to “Full screen” (on Mac Catalyst this is only “Full window” because the window does not enter full screen like AppKit apps do). The NSToolbar overlaps the “Full screen video.” On a triple Split View controller only the portions of the toolbar in the secondary and supplementary columns show through (the video actually covers the toolbar area in the “primary” column). The expected results: -For the video to cover the entire window including the NSToolbar. Actual results: The NSToolbar draw on top of the video. -- Anyone know of a workaround? I filed FB13229032

I was wondering if there is a way to programmatically invoke a Finder "quick action" from a Mac app? I know "old school" services can be invoked using NSPerformService and was looking to do something similar with a quick action. Thanks in advance.