HostingPassthrough

UIHostingController blocks all touches behind it. You basically have to choose SwiftUI, or UIKit? If you want a SwiftUI overlay over a UIKit view for example, you can't have that.

But SwiftUI and UIKit views deserve to live in harmony.

HostingPassthrough allows you to fix this by inheriting HostingParentController instead of UIViewController in the places where you will be adding SwiftUI views through UIHostingController.

• If you don't want to force your UIHostingControllers to have clear backgrounds, set makeBackgroundsClear = false in viewDidLoad().
• If you want to forward touches on the base view of the HostingParentController to another view, set forwardBaseTouchesTo to another UIView you want to handle your touches.
• You can also now inherit or initalise a HostingParentView instead of UIView, in the case that you aren't adding the UIHostingController to a parent view controller. While you should always add the UIHostingController to a parent view controller if possible to correctly manage view lifecycle, there may be instances where you are for example adding SwiftUI components to a reusable custom UIView in which case using HostingParentView would be acceptable.
• If SwiftUI ScrollView is messing up your tap targets, you can set ignoreTouchesOnSwiftUIScrollView to true so any touches that reach the bottom of a SwiftUI ScrollView (not the content), are passed to whatever is under it.

Some cool logic will then be applied overriding the hitTest method, which ignores any touches in parts of a UIHostingController that don't contain a SwiftUI view and pass it to whatever is underneath instead.

TODO:

• Fix SwiftUI .contentShape() not working.

All these views are tappable, even behind the 3 UIHostingController's!

hosting.passthrough.mov