SwiftUI views do not respond in UIKit UIViewController

Question

Created Dec ’20

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I have a Storyboard lifecycle application which has a UIViewController as window root view controller.

When I am trying to add the UIHostingController(SwiftUI view wrapped inside) to this root view controller as child view controller, the buttons and text fields in swiftUI view do not respond.

But when I am adding this UIHostingController as window root view controller or Navigation view controller's top view controller, then the swiftUI views respond in this case.

Please help me if I am missing anything

Below is the code that is used for adding the UIHostingController as child view controller which doesn't work

Code Block objective-c[self addChildViewController:hostingController];
[self.view addSubview:hostingController.view];
[hostingController didMoveToParentViewController:self];

This is the code that works (in delegate)

Code Block objective-c[window setRootViewController:hostingController];

OR this code

Code Block objective-cUINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:hostingController];
[window setRootViewController:navController];

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Answer 1

ShirleyChung OP

Apr ’21

Hi, I am searching a way to present SwiftUI wrapping in UIKit view too. My target is to integrate SwiftUI views into an existing objective-c UIKit app.
I've tried

Code Block [UIView addSubView: mySwiftUICtrl.view]

in many ways, but all get frustrated results that my SwiftUI view doesn't respond.

Finally I found a way to get my SwiftUI UIHostingController works. That is using MainViewController to present my UIHostingController:

Code Block [mainViewCtrl presentViewController:mySwiftUICtrl animated:true completion:nil];

and mySwiftUICtrl works normally.

(I guess that the mystery "msgchain" in main controller needs to be pass through the UIHostingController.)

0

Answer 2

ShirleyChung OP

May ’21

Recently I found that besides present ViewController directly, SwiftUI View can also be add to UIKit view as a subview.
For example:

Code Block  [self addChildViewController:hostingController];
 [self.view addSubview:hostingController.view];
 [hostingController didMoveToParentViewController:self];

we also need constraints swiftui in UIKit manually:

Code Block  UIView* view = hostingController.view;
 view.translatesAutoresizingMaskIntoConstraints = false;
 NSArray* constrants = [NSArray arrayWithObjects: 
			[ctrl.view.topAnchor constraintEqualToAnchor: view.topAnchor], 
			[ctrl.view.leftAnchor constraintEqualToAnchor: view.leftAnchor],
			[ctrl.view.bottomAnchor constraintEqualToAnchor: view.bottomAnchor],
			[ctrl.view.rightAnchor constraintEqualToAnchor: view.rightAnchor], nil ];
 [NSLayoutConstraint activateConstraints: constrants];

0