When initializing an @State variable, there are two initializers:
/// Initialize with the provided initial value.
public init(wrappedValue value: Value)
/// Initialize with the provided initial value.
public init(initialValue value: Value)
Is there a difference between the two initializers or are they doing the same?
Is one of them preferred to use when creating a new @State variable?
According to the swift-evolution proposal:
init(initialValue:)has been renamed toinit(wrappedValue:)to match the name of the property.
As of Swift 5.1 both are available and none is marked as deprecated. I still would recommend using init(wrappedValue:).
You don’t call this initializer(init(wrappedValue:)) directly. Instead, declare a property with the @State attribute, and provide an initial value; for example, @State private var isPlaying: Bool = false.
FYI: https://developer.apple.com/documentation/swiftui/state/3365450-init
We using init(initialValue:) to Creates the state with an initial value.
For example:
struct TestView3: View {
@ObservedObject var data = TestData.shared
@State private var sheetShowing = false
var body: some View {
print("test view3 body, glabel selected = \(data.selected)"); return
VStack {
Text("Global").foregroundColor(data.selected ? .red : .gray).onTapGesture {
self.data.selected.toggle()
}.padding()
Button(action: {
self.sheetShowing = true
print("test view3, will show test view4")
}) { Text("Show TestView4") }.padding()
}.sheet(isPresented: $sheetShowing) { TestView4(selected: self.data.selected) }
}
}
struct TestView4: View {
@ObservedObject var data = TestData.shared
@State private var selected = false
init(selected: Bool) {
self._selected = State(initialValue: selected) // <-------- here
print("test view4 init, glabel selected = \(data.selected), local selected = \(self.selected)")
}
var body: some View {
print("test view4 body, glabel selected = \(data.selected), local selected = \(selected)"); return
VStack {
Text("Local").foregroundColor(selected ? .red : .gray).onTapGesture {
self.selected.toggle()
print("test view4, local toggle")
}.padding()
Text("Global").foregroundColor(data.selected ? .red : .gray).onTapGesture {
self.data.selected.toggle()
print("test view4, global toggle")
}.padding()
}
}
}