Extraneous Argument with Binding in SwiftUI - swiftui

Question

I was playing with binding in playground using SwiftUI, it's a very simple code
struct Car:View {
var kar = "🚚"
#Binding var startAnimation: Bool = false
var body: some View {
HStack {
Spacer()
Text(kar)
.font(.custom("Arial", size: 100))
.offset(x: self.startAnimation ? 0 - UIScreen.main.bounds.width + 100: 0)
}
}
}
But playground gave an error that says "Extraneous Argument Label ", I literally see no problem, especially when i code using Xcode. so is there a way to somehow hack it or did i miss something??

Answer 1

You can not or you should not give direct value to Binding, it bind data, you should use State for example like in code
with State:
import SwiftUI
struct CarView: View {
#State private var startAnimation: Bool = Bool()
var body: some View {
VStack {
Text("🚚")
.font(Font.system(size: 100))
.offset(x: startAnimation ? 50.0 - UIScreen.main.bounds.width/2 : UIScreen.main.bounds.width/2 - 50.0)
Button("Drive!") { startAnimation.toggle() }
.font(Font.headline)
.padding()
}
.animation(.easeIn(duration: 3.0), value: startAnimation)
}
}
With Binding:
import SwiftUI
struct ContentView: View {
#State private var startAnimation: Bool = Bool()
var body: some View {
VStack {
CarView(startAnimation: $startAnimation)
Button("Drive!") {
startAnimation.toggle()
}
.font(Font.headline)
.padding()
}
.animation(.easeIn(duration: 3.0), value: startAnimation)
}
}
struct CarView: View {
#Binding var startAnimation: Bool
var body: some View {
Text("🚚")
.font(Font.system(size: 100))
.offset(x: startAnimation ? 50.0 - UIScreen.main.bounds.width/2 : UIScreen.main.bounds.width/2 - 50.0)
}
}