Navigate to new screen on button click SwiftUI - swiftui

Question

I have a login screen and wish to navigate to a new screen when the Login button is clicked.
I did try to wrap the button and the entire screen layout under NavigationView and embedded the button in a Navigation Link.
I am unable to figure out how to show the new screen when the button is clicked. Following is the code for the login screen.
ZStack {
Color.red
.edgesIgnoringSafeArea(.all)
VStack(alignment: .center, spacing: 180.0) {
Text("SwiftUI")
.font(.largeTitle)
.bold()
.padding()
VStack(alignment: .center, spacing: 25) {
TextField("Username", text: $userName)
.padding(.all)
.background(Color.white)
.cornerRadius(10)
TextField("Password", text: $userPassword)
.padding(.all)
.background(Color.white)
.cornerRadius(10)
Toggle(isOn: $isFirstTimeUser) {
Text("First Time User")
.font(.headline)
.bold()
.padding(.horizontal, -10)
.foregroundColor(Color.white)
}.padding(.horizontal, 17)
Button(action: {
if self.userName.count <= 5 {
self.isAlertShown = true
} else {
}
})
{
Text(isFirstTimeUser ? "SignUp" : "Login")
.fontWeight(.medium)
.font(.title)
.foregroundColor(Color.red)
.padding(.horizontal, 10)
}.padding()
.background(Color.white)
.cornerRadius(10)
.alert(isPresented: $isAlertShown) {
() -> Alert in
Alert(title: Text("UserName Invalid"), message: Text("Username has to be more than 5 characters"), dismissButton:.default(Text("Got that!")))
}
}.padding(.horizontal, 17)
}
}

Answer 1

Here is possible approach
1) Add link tag state variable to your View
#State private var current: Int? = nil
2) Wrap your view hierarchy into NavigationView to make possible NavigationLink to work
3) Add tagged NavigationLink above your button
NavigationLink(destination: YourDestinationViewHere(), tag: 1, selection: $current) {
EmptyView()
}
4) Add link tag selection to button action
Button(action: {
if self.userName.count <= 5 {
self.isAlertShown = true
} else {
self.current = 1 // this activates NavigationLink with specified tag
}
})