I'm working on a math game and I would like to implement a small calculator in the background with a custom half modal.
The problem is that the inputted number is not updated unless you physically dismiss the modal and open it again. Although this is an extremely stressful calculator to use, I want to have the text updated immediately after a button is pressed just like a normal calculator (except the fact that it is in a half modal but still).
Please let me know if there is something I'm missing anything and here's my code to review...
struct PGQuestion1: View {
@State var show = false
@State var showA = false
@State var showB = false
@State var showC = false
@State var showSheet: Bool = false
@State var showSheetA: Bool = false
@State var showSheet2: Bool = false
@State private var chromaShift = false
@State var value = "0"
let buttons: [[CalcButton]] = [
[.clear, .negative, .percent, .divide],
[.seven, .eight, .nine, .multiply],
[.four, .five, .six, .subtract],
[.one, .two, .three, .add],
[.zero, .decimal, .equal]
]
@State var currentOperation: Operation = .none
@State var runningNumber = 0
var body: some View {
ZStack {
Color.indigo.ignoresSafeArea()
VStack {
VStack(alignment: .leading) {
HStack {
Image(systemName: "1.circle")
.foregroundColor(.white)
.font(.largeTitle)
.padding()
Spacer()
}
}
VStack {
Text("Solve the following:")
.foregroundColor(.white)
.font(.title2)
.fontWeight(.medium)
.padding(.bottom, 44)
Text("(54-9)÷5")
.foregroundColor(.white)
.font(.system(size: 60, design: .rounded))
.fontWeight(.medium)
.padding(.bottom, 45)
VStack(spacing: 0.01) {
ZStack {
VStack {
if showA {
Rectangle()
.fill(Color.purple.opacity(0.95))
.frame(maxWidth: .infinity, maxHeight: 100)
.cornerRadius(30)
.padding()
} else {
Rectangle()
.fill(Color.white.opacity(0.5))
.frame(maxWidth: .infinity, maxHeight: 100)
.cornerRadius(30)
.padding()
}
}
.onTapGesture {
showA.toggle()
self.showB = false
self.showC = false
}
Text("9")
.font(.largeTitle)
.foregroundColor(.white)
}
ZStack {
VStack {
if showB {
Rectangle()
.fill(Color.purple.opacity(0.95))
.frame(maxWidth: .infinity, maxHeight: 100)
.cornerRadius(30)
.padding()
} else {
Rectangle()
.fill(Color.white.opacity(0.5))
.frame(maxWidth: .infinity, maxHeight: 100)
.cornerRadius(30)
.padding()
}
}
.onTapGesture {
showB.toggle()
self.showA = false
self.showC = false
}
Text("52.2")
.font(.largeTitle)
.foregroundColor(.white)
}
HStack(spacing: 20) {
Button {
showSheet.toggle()
} label: {
VStack {
ZStack {
Circle()
.fill(Color.purple.opacity(0.8))
.frame(width: 80, height: 80)
.padding(.top, 13)
.padding(.leading, 28.5)
Image(systemName: "circle.grid.3x3.fill")
.foregroundColor(.white)
.font(.largeTitle)
.padding(.top, 13)
.padding(.leading, 28.5)
}
Text("Calculator")
.foregroundColor(.white)
.padding(.bottom)
.padding(.leading, 28.5)
}
}
.halfSheet(showSheet: $showSheet) {
ZStack {
Color.black.opacity(0.9).ignoresSafeArea()
VStack {
Spacer()
// Text display
HStack {
Spacer()
Text(value)
.bold()
.font(.system(size: 70))
.foregroundColor(.white)
.minimumScaleFactor(0.5)
}
.padding(.leading)
.padding([.top, .trailing], 23)
.padding(.bottom, 2)
// Our Buttons
ForEach(buttons, id: \.self) { row in
HStack(spacing: 12) {
ForEach(row, id: \.self) { item in
Button {
self.didTap(button: item)
} label: {
Text(item.rawValue)
.font(.system(size: 36))
.frame(width: self.buttonWidth(item: item), height: 55)
.scaledToFit()
.background(item.buttonColor)
.foregroundColor(.white)
.cornerRadius(95)
}
}
}
.padding(.bottom, 0.55)
.padding([.leading, .trailing], 20)
}
}
}
}
Button {
showSheet2.toggle()
} label: {
VStack {
ZStack {
Circle()
.fill(Color.purple.opacity(0.8))
.frame(width: 80, height: 80)
.padding(.top, 13)
Image(systemName: "book")
.foregroundColor(.white)
.font(.largeTitle)
.padding(.top, 13)
}
Text("Dictonary")
.foregroundColor(.white)
.padding(.bottom)
}
}
.halfSheet(showSheet: $showSheet2) {
ZStack {
Color.black.opacity(0.9).ignoresSafeArea()
VStack(alignment: .leading) {
HStack {
}
}
}
}
VStack {
if !show {
ZStack {
Circle()
.fill(Color.purple.opacity(0.8))
.frame(width: 80, height: 80)
.blur(radius: 10)
.padding(.top, 13)
.padding(.trailing)
Image(systemName: "info")
.foregroundColor(.black)
.font(.largeTitle)
.padding(.top, 13)
.padding(.trailing)
}
.onTapGesture {
withAnimation {
show.toggle()
}
}
} else {
ZStack {
Circle()
.fill(Color.purple.opacity(0.8))
.frame(width: 80, height: 80)
.blur(radius: 10.35)
.padding(.top, 13)
.padding(.trailing)
Text("Upgrade to Mathematically MAX")
.foregroundColor(.black)
.font(.system(size: 13))
.minimumScaleFactor(0.5)
.multilineTextAlignment(.center)
.padding(.top, 16)
.padding(1)
.padding(4)
.padding(5)
.padding(.trailing)
}
.onTapGesture {
withAnimation {
show.toggle()
}
}
}
Text("Intelligent Finding")
.foregroundColor(.black)
.font(.system(size: 12))
.padding(.top, 2)
.padding(.bottom)
.padding(.trailing)
}
}
.frame(maxWidth: .infinity, maxHeight: 140)
.background(Color.white.opacity(0.3))
.cornerRadius(40)
.padding()
}
}
HStack {
ZStack {
Text("Swipe to the next page")
.font(.title2)
.foregroundColor(Color.yellow)
.shadow(color: .white, radius: 10)
.hueRotation(.degrees(chromaShift ? 0 : 520))
.animation(Animation.linear(duration: 4).repeatForever(autoreverses: true))
.onAppear() {
self.chromaShift.toggle()
}
}
Image(systemName: "chevron.forward")
.font(.title2)
.foregroundColor(Color.yellow)
.shadow(color: .white, radius: 10)
.hueRotation(.degrees(chromaShift ? 0 : 520))
.animation(Animation.linear(duration: 4).repeatForever(autoreverses: true))
.onAppear() {
self.chromaShift.toggle()
}
}
Spacer()
}
}
}
func didTap(button: CalcButton) {
switch button {
case .add, .subtract, .multiply, .divide, .equal:
if button == .add {
self.currentOperation = .add
self.runningNumber = Int(self.value) ?? 0
} else if button == .subtract {
self.currentOperation = .subtract
self.runningNumber = Int(self.value) ?? 0
} else if button == .multiply {
self.currentOperation = .multiply
self.runningNumber = Int(self.value) ?? 0
} else if button == .divide {
self.currentOperation = .divide
self.runningNumber = Int(self.value) ?? 0
} else if button == .equal {
let runningValue = self.runningNumber
let currentValue = Int(self.value) ?? 0
switch self.currentOperation {
case .add:
self.value = "\(runningValue currentValue)"
case .subtract:
self.value = "\(runningValue - currentValue)"
case .multiply:
self.value = "\(runningValue * currentValue)"
case .divide:
self.value = "\(runningValue / currentValue)"
case .none:
break
}
}
if button != .equal {
self.value = "0"
}
case .clear:
self.value = "0"
case .decimal, .percent, .negative:
break
default:
let number = button.rawValue
if self.value == "0" {
value = number
} else {
self.value = "\(self.value)\(number)"
}
}
}
func buttonWidth(item: CalcButton) -> CGFloat {
if item == .zero {
return ((UIScreen.main.bounds.width - (4*12)) / 4) * 2
}
return (UIScreen.main.bounds.width - (5*12)) / 4
}
func buttonHeight() -> CGFloat {
return (UIScreen.main.bounds.height - (5*12)) / 4
}
}
enum CalcButton: String {
case one = "1"
case two = "2"
case three = "3"
case four = "4"
case five = "5"
case six = "6"
case seven = "7"
case eight = "8"
case nine = "9"
case zero = "0"
case add = " "
case subtract = "-"
case divide = "÷"
case multiply = "×"
case equal = "="
case clear = "AC"
case decimal = "."
case percent = "%"
case negative = " /-"
var buttonColor: Color {
switch self {
case .add, .subtract, .multiply, .divide, .equal:
return .orange
case .clear, .negative, .percent:
return .gray
default:
return Color(UIColor(red: 55/255.0, green: 55/255.0, blue: 55/255.0, alpha: 1))
}
}
}
enum Operation {
case add, subtract, multiply, divide, none
}
extension View {
func halfSheet<SheetView: View>(showSheet: Binding<Bool>, @ViewBuilder sheetView: @escaping () -> SheetView) -> some View {
return self
.background(
HalfSheetHelper(sheetView: sheetView(), showSheet: showSheet)
)
}
}
struct HalfSheetHelper<SheetView: View>: UIViewControllerRepresentable {
var sheetView: SheetView
@Binding var showSheet: Bool
let controller = UIViewController()
func makeUIViewController(context: Context) -> UIViewController {
controller.view.backgroundColor = .clear
return controller
}
func updateUIViewController(_ uiViewController: UIViewController, context: Context) {
let sheetController = CustomHostingController(rootView: sheetView)
if showSheet {
uiViewController.present(sheetController, animated: true) {
DispatchQueue.main.async {
self.showSheet.toggle()
}
}
}
}
}
class CustomHostingController<Content: View>: UIHostingController<Content> {
override func viewDidLoad() {
if let presentationController = presentationController as? UISheetPresentationController {
presentationController.detents = [
.medium(),
.large()
]
presentationController.prefersGrabberVisible = true
}
}
}
CodePudding user response：
The problem is in your func halfSheet() and struct HalfSheetHelper. You have created a UIViewControllerRepresentable view, but it does not handle updates.
Once the sheet has already been shown, the sequence of events happening is:
- Pressing a button triggers a change to
self.valueinsidePGQuestion1. - SwiftUI re-renders
PGQuestion1, and a new closure is passed to.halfSheet { ... }which uses the newvalue. - Since the
HalfSheetHelperisUIViewRepresentable, SwiftUI calls yourupdateUIViewController()function. A completely new CustomHostingController is created. Then nothing else happens becauseshowSheetisfalse.
To handle updates properly, I recommend you create a Coordinator class inside your HalfSheetHelper. The coordinator is a class that SwiftUI will keep alive as long as the view is being used, and it can maintain a persistent reference to the CustomHostingController. Then in updateUIViewController(), you can use the coordinator to access the hosting controller and re-assign its rootView with the newly updated sheet contents. For more on these techniques, see the Interfacing with UIKit tutorial.
I also changed how showSheet is handled so that it becomes false only once the sheet is dismissed. This required adding a custom onDismiss closure to the CustomHostingController which it calls in viewDidDisappear.
(There still seems to be a bug with the half-sheet, where if I swipe down to dismiss the sheet and then show it again, it appears fullscreen instead of half-screen. I'm not familiar enough with the presentationController/detents APIs to figure out why this is happening!)
struct HalfSheetHelper<SheetView: View>: UIViewControllerRepresentable {
var sheetView: SheetView
@Binding var showSheet: Bool
class Coordinator {
let dummyController = UIViewController()
let sheetController: CustomHostingController<SheetView>
init(sheetView: SheetView, showSheet: Binding<Bool>) {
sheetController = CustomHostingController(rootView: sheetView, onDismiss: { showSheet.wrappedValue = false })
dummyController.view.backgroundColor = .clear
}
}
func makeCoordinator() -> Coordinator {
return Coordinator(sheetView: sheetView, showSheet: $showSheet)
}
func makeUIViewController(context: Context) -> UIViewController {
return context.coordinator.dummyController
}
func updateUIViewController(_ uiViewController: UIViewController, context: Context) {
context.coordinator.sheetController.rootView = sheetView
if showSheet && uiViewController.presentedViewController == nil {
uiViewController.present(context.coordinator.sheetController, animated: true)
}
}
}
class CustomHostingController<Content: View>: UIHostingController<Content> {
var onDismiss: (() -> Void)?
convenience init(rootView: Content, onDismiss: @escaping () -> Void) {
self.init(rootView: rootView)
self.onDismiss = onDismiss
}
override func viewDidLoad() {
if let presentationController = presentationController as? UISheetPresentationController {
presentationController.detents = [
.medium(),
.large()
]
presentationController.prefersGrabberVisible = true
}
}
override func viewDidDisappear(_ animated: Bool) {
onDismiss?()
}
}
CodePudding user response：
to make the value show in the halfSheet Text,
I used the code at: https://www.keaura.com/blog/sheets-with-swiftui
instead of the halfSheet you provided. Also, I "attached" this new halfSheet
to the View ZStack, like this:
var body: some View {
ZStack {
....
}
.halfSheet(isPresented: $showSheet) { ... }
.halfSheet(isPresented: $showSheet2) { ... }