SwiftUI - Showing and hiding a custom alert - ios

Question

I am creating a custom alert reusable modifier which will have different number of buttons depending upon the style I need. Anyways in my sample code below, I have removed as much extra code as I can to keep it small and simple.
With the code below, I am able to show the alert, but clicking on "Click Me" button does not dismiss the alert. I feel something is wrong with the way I am setting "isPresented" binding variable, but not able to figure out what. Am new to SwiftUI.
Custom Alert Modifier:
struct CustomAlertView: ViewModifier {
var isPresented: Binding<Bool>
init(isPresented: Binding<Bool>) {
self.isPresented = isPresented
}
func body(content: Content) -> some View {
content.overlay(alertContent())
}
#ViewBuilder
private func alertContent() -> some View {
GeometryReader { geometry in
if self.isPresented {
// Do something
// Setting isPresented to false is not doing anything when button is clicked.
Button(action: { self.isPresented.wrappedValue = false }) {
Text("Click Me")
}
}
}
}
}
func customAlert(isPresented: Binding<Bool>) -> some View {
return modifier(CustomAlertView(isPresented: isPresented))
}
View and view model code:
struct MyView: View {
#ObservedObject var viewModel: CustomViewModel = CustomViewModel()
var body: some View {
VStack {
switch viewModel.state {
case .idle:
Color.clear.onAppear(perform: { viewModel.doSomething() })
case .showNewView:
// Navigate
}
}.onAppear() {
viewModel.state = .idle
}.customAlert(isPresented: .constant(viewModel.showAlert))
}
}
#MainActor
class CustomViewModel: ObservableObject {
enum State {
case idle
case showNewView
}
#Published var state = State.idle
#Published var showAlert = false
func doSomething() {
if failure {
self.showAlert = true
} else {
self.state = .showNewView
}
}
}
What am I doing wrong or why am I not able to dismiss the alert?
Thanks for looking!

Answer 1

First of all, you want #Binding var isPresented: Bool inside the CustomAlertView, and you assign it in init as self._isPresented = isPresented:
struct CustomAlertView: ViewModifier {
#Binding var isPresented: Bool // <-- like this
init(isPresented: Binding<Bool>) {
self._isPresented = isPresented // <-- and like this
}
//...
And second, you definitely don't want to set isPresented to a constant in .customAlert(isPresented: .constant(viewModel.showAlert)). Instead, you need to pass the binding variable:
VStack {
// ...
}
.customAlert(isPresented: $viewModel.showAlert) // <-- bind it here