How to make SwiftUI View expand available space?

Question

I am trying to make a SwiftUI View expand its available space. I have a MapView which uses the MapKit to display a map on the screen. I would like this map to expand the available space in the VStack. You can see it is above a view colored red, and below a search bar. If i make the red colored view have a height of 100, then the MapView shrinks down. If I do not set the height on the red colored view, then the MapView is bigger however the red view does not look as I want.

I want the red view to have a height of 100, and the MapView to fill all available height underneath the search bar, and above the red view.

ContentView:

struct ContentView: View {

@ObservedObject
var viewModel: HomeViewModel

var body: some View {
    NavigationView {
        ZStack {
            ColorTheme.brandBlue.value.edgesIgnoringSafeArea(.all)
            VStack {
                CardView {
                    EditText(hint: "Search", text: self.$viewModel.searchText, textContentType: UITextContentType.organizationName)
                }
                MapView(annotations: self.$viewModel.restaurantAnnotations)
                    .cornerRadius(8)
                CardView(height: 100) {
                    HStack {
                        Color.red

                    }
                }
            }
        }
        .navigationBarTitle("", displayMode: .inline)
        .navigationBarHidden(true)
        .navigationBarBackButtonHidden(true)
    }
}
}

CardView

struct CardView<Content>: View where Content : View {
var height: CGFloat = .infinity
var content: () -> Content
var body: some View {
    content()
        .padding(EdgeInsets.init(top: 0, leading: 8, bottom: 8, trailing: 8))
    .background(Color.white.cornerRadius(8))
        .shadow(radius: 2, x: 0, y: 1)
        .frame(minWidth: 0, maxWidth: .infinity, minHeight: 0, maxHeight: height)
}
}

EditText

struct EditText: View {

var hint: String
@Binding
var text: String
var label: String = ""
var textContentType: UITextContentType? = .none
var keyboardType: UIKeyboardType = .default
var textSize: CGFloat = 16

var body: some View {
    return VStack(alignment: .leading) {
        Text(label).font(.system(size: 12)).bold()
            .foregroundColor(ColorTheme.text.value)
        HStack {
            TextField(hint, text: $text)
                .lineLimit(1)
                .font(.system(size: textSize))
                .textContentType(textContentType)
                .keyboardType(keyboardType)
                .foregroundColor(ColorTheme.text.value)
        }
        Divider().background(ColorTheme.brandBlue.value)
    }
}
}

MapView

struct MapView: UIViewRepresentable {

@Binding
var annotations: [MKAnnotation]

func makeUIView(context: Context) -> MKMapView {
    let mapView = MKMapView()
    mapView.delegate = context.coordinator
    return mapView
}


func updateUIView(_ view: MKMapView, context: Context) {
    view.delegate = context.coordinator
    view.addAnnotations(annotations)
    if annotations.count == 1 {
        let coords = annotations.first!.coordinate
        let region = MKCoordinateRegion(center: coords, span: MKCoordinateSpan(latitudeDelta: 0.1, longitudeDelta: 0.1))
        view.setRegion(region, animated: true)
    }

}

func makeCoordinator() -> MapViewCoordinator {
    MapViewCoordinator(self)
}
}

MapViewCoordinator

class MapViewCoordinator: NSObject, MKMapViewDelegate {

var mapViewController: MapView

init(_ control: MapView) {
    self.mapViewController = control
}


func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView?{
    //Custom View for Annotation
    let identifier = "Placemark"
    if  let annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: identifier) {
        annotationView.annotation = annotation
        return annotationView
    } else {
        let annotationView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: identifier)
        annotationView.isEnabled = true
        annotationView.canShowCallout = true
        let button = UIButton(type: .infoDark)
        annotationView.rightCalloutAccessoryView = button
        return annotationView
    }

    return nil
}
}

As you can see the MapView does not fill the available space

Now all the available space is filled but the red view height is not 100

Asperi Asperi · Accepted Answer · 2020-05-05T03:45:37

Here is a solution (tested with Xcode 11.4):

struct CardView<Content>: View where Content : View {
    var height: CGFloat? = nil // << here !!

Note: defined height, even with .infinity, made your upper card equivalent by requesting height to map view, so they divided free space; when height is not specified, the component tights to content

How to make SwiftUI View expand available space?

1 Answers