How can I transfer DragGesture to separate function in SwiftUI? - swiftui

Question

I have simple View which has 2 DragGesture, first one updating and second one onEnded, I want make my body cleaner and i want transfer those functions how we can do that? I think those are kind of clouser functions.
struct ContentView: View {
#State private var location: CGSize = CGSize()
#GestureState private var translation: CGSize = CGSize()
var body: some View {
Circle()
.fill()
.frame(width: 100, height: 100, alignment: .center)
.position(x: location.width + translation.width + 100, y: location.height + translation.height + 100)
.gesture(
DragGesture()
// transfer to updatingFunction
.updating($translation) { value, state, _ in
state = value.translation
}
// transfer to onEndedFunction
.onEnded { value in onEndedFunction(value: value)}
)
}
func updatingFunction() {
}
func onEndedFunction(value: DragGesture.Value) {
location = CGSize(width: location.width + value.translation.width, height: location.height + value.translation.height)
}
}

Answer 1

You can use inout for passing state.
struct ContentViewGesture: View {
#State private var location: CGSize = CGSize()
#GestureState private var translation: CGSize = CGSize()
var body: some View {
Circle()
.fill()
.frame(width: 100, height: 100, alignment: .center)
.position(x: location.width + translation.width + 100, y: location.height + translation.height + 100)
.gesture(
DragGesture()
// transfer to updatingFunction
.updating($translation) { value, state, _ in
updatingFunction(value: value, state: &state) //<<-- Here
}
// transfer to onEndedFunction
.onEnded { value in onEndedFunction(value: value)}
)
}
func updatingFunction(value: DragGesture.Value, state: inout CGSize) { //<<-- Here
state = value.translation
}
func onEndedFunction(value: DragGesture.Value) {
location = CGSize(width: location.width + value.translation.width, height: location.height + value.translation.height)
}
}

Answer 2

It does not look much reasonable, instead I would recommend to separate entire gesture (if you look for code simplification, readability, etc.)
Here is possible variant:
struct ContentView: View {
#State private var location: CGSize = CGSize()
#GestureState private var translation: CGSize = CGSize()
private var dragGesture: some Gesture {
DragGesture()
.updating($translation) { value, state, _ in
state = value.translation
}
.onEnded { value in
location = CGSize(width: location.width + value.translation.width, height: location.height + value.translation.height)
}
}
var body: some View {
Circle()
.fill()
.frame(width: 100, height: 100, alignment: .center)
.position(x: location.width + translation.width + 100, y: location.height + translation.height + 100)
.gesture(dragGesture)
}
}