SwiftUI - EnvironmentObject - Strange Memory Usage - ios

Question

I've got some strange results with the memory usage in my SwiftUI App. Below you see a minimal example I've build.
/// Test file for strange behaviour with EnvironmentObject
/// The RAM Usage is increased if we click the button in View "Settings" and switch back to "MapView"
import SwiftUI
import MapKit
class Model: ObservableObject {
#Published var coolBool: Bool = false {
didSet {
print(coolBool.description)
}
}
}
struct MapView: UIViewRepresentable {
private let mapView = MKMapView(frame: .zero)
func makeUIView(context: Context) -> MKMapView {
return mapView
}
func updateUIView(_ uiView: MKMapView, context: Context) {
}
}
struct Settings: View {
#EnvironmentObject var model: Model
var body: some View {
Form {
Button(action: {self.model.coolBool.toggle()}) {
Text(self.model.coolBool.description)
}
}
}
}
struct ContentView: View {
#EnvironmentObject var model: Model
var body: some View {
TabView() {
MapView().tabItem {
Image(systemName: "map")
Text("1")
}
Settings().tabItem {
Image(systemName: "gear")
Text("2")
}
Text("Just a screen").tabItem {
Image(systemName: "sunrise")
Text("3")
}
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
Scenario:
Open App
You will see MapView, the memory usage is stable
Go to Tab 2
Click the button which will change the EnvironmentObject, memory usage still stable
Go to Tab 3, memory usage is the same
Go to Tab 1 (MapView), memory usage is increased
If you redo 3, 4, 6 you will see that the memory usage is going bigger and bigger.
Can someone explain this to me?
The memory usage will start at ~40 MB, if I tap the button -> go to MapView -> tap the button -> go to MapView -> .... the memory usage will increase. I got a memory usage of ~500 MB

Answer 1

Try the following
struct MapView: UIViewRepresentable {
func makeUIView(context: Context) -> MKMapView {
MKMapView(frame: .zero) // created here is managed by SwiftUI
}
func updateUIView(_ uiView: MKMapView, context: Context) {
}
}
Alternate: if you definitely want the one map view - use static
struct MapView: UIViewRepresentable {
private let static mapView = MKMapView(frame: .zero)
func makeUIView(context: Context) -> MKMapView {
MapView.mapView
}
func updateUIView(_ uiView: MKMapView, context: Context) {
}
}