CS193p Notes - Lecture 14: UIKit Integration

#ios #swift

UIKit is the old way of developing iOS apps
SwfitUI (which we have learned in this course) replaced it and is doing most of the things
There are still some things that might be better in UIKit or there might be some old code so it's important to understand how to use it in SwiftUI

Instead of having MVVM there is MVC
- In MVC views are grouped together and controlled by aController
UIKit is object-oriented (not functional)

UIKit uses a concept "delegation"
- Objects (controllers and views) often delegate some of their functionality to other objects
- They do this by having a var calleddelegate
- delegate var is constrained via a protocol with all the delegatable functionality

Enroute demo UIView (12:25)

We createMapView to normal Swift file (not SwiftUI) because there isn'tvar body

This will draw a map and add pins to the points mentioned inannotations

importSwfitUIimportUIKitimportMapKitstructMapView:UIViewRepresentable{letannotations:[MKAnnotation]funcmakeUIView(context:Context)->MKMapView{letmkMapView=MKMapView()mkMapView.delegate=context.coordinatormkMapView.addAnnotations(self.annotations)returnmkMapView}funcupdateUIView(_uiView:MKMapView,context:Context){}funcmakeCoordinator()->Coordinator{returnCoordinator()}classCoordinator:NSObject,MKMapViewDelegate{funcmapView(_mapView:MKMapView,viewForannotation:MKAnnotation)->MKAnnotationView?{letview=mapView.dequeueReusableAnnotationView(withIdentifier:"MapViewAnnotation")??MKPinAnnotationView(annotation:annotation,reuseIdentifier:"MapViewAnnotation")view.canShowCallout=truereturnview}}}

EmojiArt demo UIViewController (39:13)

importSwiftUIimportUIKittypealiasPickedImageHandler=(UIImage?)->VoidstructImagePicker:UIViewControllerRepresentable{// could be handled using binding but wanted to show// that there are different waysvarhandlePickedImage:PickedImageHandlerfuncmakeUIViewController(context:Context)->UIImagePickerController{letpicker=UIImagePickerController()picker.sourceType=.photoLibrarypicker.delegate=context.coordinatorreturnpicker}funcupdateUIViewController(_uiViewController:UIImagePickerController,context:Context){}funcmakeCoordinator()->Coordinator{Coordinator(handlePickedImage:handlePickedImage)}classCoordinator:NSObject,UIImagePickerControllerDelegate,UINavigationControllerDelegate{varhandlePickedImage:PickedImageHandlerinit(handlePickedImage:@escapingPickedImageHandler){self.handlePickedImage=handlePickedImage}funcimagePickerController(_picker:UIImagePickerController,didFinishPickingMediaWithInfoinfo:[UIImagePickerController.InfoKey:Any]){handlePickedImage(info[.originalImage]as?UIImage)}funcImagePickerControllerDidCancel(_picker:UIImagePickerController){handlePickedImage(nil)}}}