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This tutorial shows a simple example on how to use: ObservableObject, @Published, @ObservedObject.
When Property marked as @Published is changed, body Property of any View that uses that Property will be redrawn.
So it has the same purpose as @State for struct.
@Published can be used only inside a Class that implements ObservableObject Protocol.
Instance of such Class must be flagged with @ObservedObject.
This tells SwiftUI that you actually want to observe this Object in order to use this feature.
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As soon as the View is loaded Property name is changed to "Bill" and the View is redrawn with this new value.
ContentView.swift
import SwiftUI
class Person : ObservableObject {
@Published var name = "John"
}
struct ContentView: View {
@ObservedObject var person = Person()
var body: some View {
VStack {
Button("Button") { self.person.name = "Bill" } //Change name Propert in Class Instance
Text(person.name) //Change to name is detected and View is redrawn
TextField("Enter Name", text: $person.name) //Reference to person.
}
}
}
