How to properly update a modifier? - swift

Question

I'm trying to have every object in the view be shifted up when a text field is present, and to reduce amount of code, I tried making the modifiers into a modifier class, but the issue is when the y value gets changed for the keyboard handlers, it doesn't move. This exact code works if you don't use the separate function, so I don't know what's wrong.
I've tried making the value of the y a state in the modifier, but it still doesn't update - and like I said, it works if it's not in the custom modifier.
ContentView.swift
struct ContentView: View {
#State private var name = Array<String>.init(repeating: "", count: 3)
#ObservedObject private var kGuardian = KeyboardGuardian(textFieldCount: 1)
var body: some View {
Background {
VStack {
Group {
Text("Some filler text").font(.largeTitle)
Text("Some filler text").font(.largeTitle)
}
TextField("enter text #1", text: self.$name[0])
.textFieldStyle(RoundedBorderTextFieldStyle())
TextField("enter text #2", text: self.$name[1])
.textFieldStyle(RoundedBorderTextFieldStyle())
TextField("enter text #3", text: self.$name[2])
.textFieldStyle(RoundedBorderTextFieldStyle())
.background(GeometryGetter(rect: self.$kGuardian.rects[0]))
}
}.modifier(BetterTextField(kGuardian: kGuardian, slide: kGuardian.slide))
}
}
KeyboardModifications.swift
struct GeometryGetter: View {
#Binding var rect: CGRect
var body: some View {
GeometryReader { geometry in
Group { () -> AnyView in
DispatchQueue.main.async {
self.rect = geometry.frame(in: .global)
}
return AnyView(Color.clear)
}
}
}
}
final class KeyboardGuardian: ObservableObject {
public var rects: Array<CGRect>
public var keyboardRect: CGRect = CGRect()
// keyboardWillShow notification may be posted repeatedly,
// this flag makes sure we only act once per keyboard appearance
public var keyboardIsHidden = true
#Published var slide: CGFloat = 0
var appearenceDuration : Double = 0
var showField: Int = 0 {
didSet {
updateSlide()
}
}
init(textFieldCount: Int) {
self.rects = Array<CGRect>(repeating: CGRect(), count: textFieldCount)
NotificationCenter.default.addObserver(self, selector: #selector(keyBoardWillShow(notification:)), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyBoardWillHide(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)
}
deinit {
NotificationCenter.default.removeObserver(self)
}
#objc func keyBoardWillShow(notification: Notification) {
guard let duration = notification.userInfo?[UIResponder.keyboardAnimationDurationUserInfoKey] as? Double else {return}
appearenceDuration = duration
if keyboardIsHidden {
keyboardIsHidden = false
if let rect = notification.userInfo?["UIKeyboardFrameEndUserInfoKey"] as? CGRect {
keyboardRect = rect
updateSlide()
}
}
}
#objc func keyBoardWillHide(notification: Notification) {
keyboardIsHidden = true
updateSlide()
}
func updateSlide() {
if keyboardIsHidden {
slide = 0
} else {
let tfRect = self.rects[self.showField]
let diff = keyboardRect.minY - tfRect.maxY
if diff > 0 {
slide += diff
} else {
slide += min(diff, 0)
}
}
}
}
struct Background<Content: View>: View {
private var content: Content
init(#ViewBuilder content: #escaping () -> Content) {
self.content = content()
}
var body: some View {
Color.white
.frame(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
.overlay(content)
}
}
The custom modifier class:
struct BetterTextField: ViewModifier {
public var kGuardian : KeyboardGuardian
#State public var slide : CGFloat
func body(content: Content) -> some View {
content
.offset(y: slide).animation(.easeIn(duration: kGuardian.appearenceDuration))
.onTapGesture {
let keyWindow = UIApplication.shared.connectedScenes
.filter({$0.activationState == .foregroundActive})
.map({$0 as? UIWindowScene})
.compactMap({$0})
.first?.windows
.filter({$0.isKeyWindow}).first
keyWindow!.endEditing(true)
}
}
}
What should happen is the entire screen should shift up with the keyboard, but it stays as it is. I've been trying things for around 2 hours to no avail.

Answer 1

I guess your slide variable is not updated. Try with the following change code in BetterTextField modifier:
struct BetterTextField: ViewModifier {
#ObservedObject var kGuardian : KeyboardGuardian
func body(content: Content) -> some View {
content
.offset(y: kGuardian.slide).animation(.easeIn(duration: kGuardian.appearenceDuration))
.onTapGesture {
let keyWindow = UIApplication.shared.connectedScenes
.filter({$0.activationState == .foregroundActive})
.map({$0 as? UIWindowScene})
.compactMap({$0})
.first?.windows
.filter({$0.isKeyWindow}).first
keyWindow!.endEditing(true)
}
}
}