Hi,
Is there an equivalent to UIKit's `touchesBegan`, `touchesMoved`, etc., in SwiftUI?
If I want to create an advanced custom view, with the exact kind of interaction that I envision, in UIKit I'd implement `touchesMoved` and friends, keep some state machine in my view, and draw things in `drawRect`. I understand that in SwiftUI you can replace `drawRect` with `Shape`s. But what about the low level touch handling?
Look at the @GestureState property wrapper. This allows you to bind the state of a drag gesture into a property whose value can then be used to drive layout of the UI. A simple use for this is to use it along with a GeometryReader to get a coordinate for the gesture's current point anchor to put a moveable view at a specific coordinate on the screen. I'll see if I can code up a quick example & post it here.
As promised, here's a sample:
import SwiftUI
struct ContentView: View {
@GestureState var translation: CGSize = .zero
var body: some View {
Circle()
.fill(Color.blue)
.frame(width: 100, height: 100)
.offset(translation)
.gesture(DragGesture().updating($translation) { value, state, _ in
state = value.translation
})
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}