I want to show an image for one second when the player achieve the goal. I thought about putting an alert but it will slow down the game. I just want the image to stay for one second at the top of the screen and disappear until the next achievement.
Example code is below:
var TapNumber = 0
func ScoreUp() {
TapNumber += 1
if TapNumber == 100 {
showImage()
}
}
func showImage() {
// this is the function I want to create but. I do not know how
show image("YouEarnedAPointImage") for one second
}
Here is a demo of possible approach
struct DemoShowImage1Sec: View {
#State private var showingImage = false
var body: some View {
ZStack {
VStack {
Text("Main Content")
Button("Simulate") { self.showImage() }
}
if showingImage {
Image(systemName: "gift.fill")
.resizable()
.frame(width: 100, height: 100)
.background(Color.yellow)
}
}
}
private func showImage() {
self.showingImage = true
DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
self.showingImage = false
}
}
}
Related
I have a grid of items. Each item can expand height. I want to autoscroll when the item is expanded so it doesn't overflow the screen.
I was successful with the following code but I had to revert to a hack.
The idea was to detect when the item is overflowing using a Geometry reader on the item's background. Works wonders.
The issue is that when the view is expanded , the geo reader will update after the condition to check if autoscroll should execute is ran by the dispatcher. Hence my ugly hack.
Wonder what is the proper way ?
import SwiftUI
struct BlocksGridView: View {
private var gridItemLayout = [GridItem(.adaptive(minimum: 300, maximum: .infinity), spacing: 20)]
var body: some View {
ZStack{
ScrollView {
ScrollViewReader { value in
LazyVGrid(columns: gridItemLayout, spacing: 20) {
ForEach((0..<20), id: \.self) {
BlockView(cardID: $0,scrollReader: value).id($0)
}
}
}
.padding(20)
}
}
}
}
struct BlockView : View {
var cardID : Int
var scrollReader : ScrollViewProxy
#State private var isOverflowingScreen = false
#State private var expand = false
var body: some View {
ZStack{
Rectangle()
.foregroundColor(isOverflowingScreen ? Color.blue : Color.green)
.frame(height: expand ? 300 : 135)
.clipShape(Rectangle()).cornerRadius(14)
.overlay(Text(cardID.description))
.background(GeometryReader { geo -> Color in
DispatchQueue.main.async {
if geo.frame(in: .global).maxY > UIScreen.main.bounds.maxY {
isOverflowingScreen = true
} else {
isOverflowingScreen = false
}
}
return Color.clear
})
.onTapGesture {
expand.toggle()
DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) { // <-- Hack :(
if isOverflowingScreen {
withAnimation{
scrollReader.scrollTo(cardID)
}
}
}
}
}
}
}
struct BlocksGridView_Previews: PreviewProvider {
static var previews: some View {
BlocksGridView()
}
}
Blue items are overflowing ...
I would like to scale some view with animation and go back to the original scale. The way I figured out to do it is by using DispatchQueue.main.asyncAfter with deadline matching the end of scale up animation. As shown in following code. My question is if there is better way to do that (more SwiftUI way, or just simpler).
import SwiftUI
struct ExampleView: View {
#State private var isPulse = false
var body: some View {
VStack {
Text("Hello")
.scaleEffect(isPulse ? 3 : 1)
ZStack {
Capsule()
.frame(width: 100, height: 40)
.foregroundColor(.pink)
Text("Press me")
}
.onTapGesture {
let animationDuration = 0.4
withAnimation(.easeInOut(duration: animationDuration)) {
isPulse.toggle()
}
DispatchQueue.main.asyncAfter(deadline: .now() + animationDuration) {
withAnimation(.easeInOut) {
isPulse.toggle()
}
}
}
}
}
}
struct ExampleView_Previews: PreviewProvider {
static var previews: some View {
ExampleView()
}
}
Pulse animation
You can use two withAnimation statements with the second one that scales the text down using a .delay(animationDuration):
.onTapGesture {
let animationDuration = 0.4
withAnimation(.easeInOut(duration: animationDuration)) {
isPulse.toggle()
}
withAnimation(.easeInOut(duration: animationDuration).delay(animationDuration)) {
isPulse.toggle()
}
}
You could also replace the two calls to withAnimation with a for loop:
.onTapGesture {
let animationDuration = 0.4
for delay in [0, animationDuration] {
withAnimation(.easeInOut(duration: animationDuration).delay(delay)) {
isPulse.toggle()
}
}
}
I have a view like following
struct A: View {
var content: AnyView
var body: some View {
ScrollView(.vertical, showsIndicators: false) {
VStack {
// Common Elements
content
// More Common Elements
}
}
}
}
When I call this from another view like
A(nextInnerView())
two things happen. Firstly, as the size of the content element changes ScrollView animates the transition. Secondly, if you scroll down and then change the content the scrolling position does not reset.
Here is a demo of possible solution. Tested with Xcode 11.4 / iOS 13.4
The origin of this behaviour is in SwiftUI rendering optimisation, that tries to re-render only changed part, so approach is to identify view A (to mark it as completely changed) based on condition that originated in interview changes, alternatively it can be identified just by UUID().
struct TestInnerViewReplacement: View {
#State private var counter = 0
var body: some View {
VStack {
Button("Next") { self.counter += 1 }
Divider()
A(content: nextInnerView())
.id(counter) // << here !!
}
}
private func nextInnerView() -> AnyView {
AnyView(Group {
if counter % 2 == 0 {
Text("Text Demo")
} else {
Image(systemName: "star")
.resizable()
.frame(width: 100, height: 100)
}
})
}
}
struct A: View {
var content: AnyView
var body: some View {
ScrollView(.vertical, showsIndicators: false) {
VStack {
ForEach(0..<5) { _ in // upper content demo
Rectangle().fill(Color.yellow)
.frame(height: 40)
.frame(maxWidth: .infinity)
.padding()
}
content
ForEach(0..<10) { _ in // lower content demo
Rectangle().fill(Color.blue)
.frame(height: 40)
.frame(maxWidth: .infinity)
.padding()
}
}
}
}
}
I am new to SwiftUI and have managed to build simple game.
All works except my plan to implement some sort of image animation / transition to introduce the image into the view.
The images are formatted correctly, but too abrupt and hoped to soften the image glow
I have tried by using the animation method, but has not mad a difference.
I hope someone can point me in the right direction.
var body: some View {
NavigationView {
ZStack {
Image("background")
.resizable()
.aspectRatio(contentMode: .fill)
.scaledToFill()
.edgesIgnoringSafeArea(.all)
VStack {
Text("Tap Correct Image")
.font(.headline)
.foregroundColor(Color.blue)
ForEach((0...2), id: \.self) { number in
Image(self.naijaObject[number])
.resizable()
.frame(width: 100, height: 100)
.border(Color.black,width: 1)
.transition(.slide)
.animation(.easeInOut(duration: 1))
.onTapGesture {
self.pictureTapped(number)
}
}
.navigationBarTitle(Text(processCorrectAnswer))
.alert(isPresented: $showAlert) {
Alert(title: Text("\(alertTitle), Your score is \(score)"), dismissButton: .default(Text("Continue")) {
self.askQuestion()
})
}
}//End of VStack
}//End of
} //End of Naviagtion View
} //End of View
//Function to action which object is tapped
func pictureTapped(_ tag: Int) {
if tag == correctAnswer {
score += 1
alertTitle = "Correct"
} else {
score -= 1
alertTitle = "Wrong"
}
showAlert = true
}
//Function to continue the game
func askQuestion() {
naijaObject.shuffle()
correctAnswer = Int.random(in: 0...2)
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
I think I understand, what you want to achieve, but in future better to present more code. Here I used DispatchQueue.main.asyncAfter(deadline: .now() + 1) where I change the variable showAlert to true. And it works smoothly, hope it'll help you:
struct QuestionGame: View {
#State private var showAlert = false
#State private var score: Int = 0
#State private var correctAnswer = 1
#State private var tapped = false
var body: some View {
NavigationView {
VStack {
Text("Tap Correct Image")
.font(.headline)
ForEach((0...2), id: \.self) { number in
Rectangle()
.frame(width: 100, height: 100)
.foregroundColor(self.tapped && number == self.correctAnswer ? .green : .black) // you can do anything for animation
.animation(.easeInOut(duration: 1.0))
.onTapGesture {
self.pictureTapped(number)
}
}
.navigationBarTitle(Text("answer the question"))
.alert(isPresented: self.$showAlert) {
Alert(title: Text("Your score is \(score)"), dismissButton: .default(Text("Continue")) {
self.askQuestion()
})
}
}
}
}
func pictureTapped(_ tag: Int) {
tapped = true
if tag == correctAnswer {
score += 1
} else {
score -= 1
}
DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
self.showAlert = true
}
}
//Function to continue the game
func askQuestion() {
tapped = false
showAlert = false
correctAnswer = Int.random(in: 0...2)
}
}
struct QuestionGame_Previews: PreviewProvider {
static var previews: some View {
QuestionGame()
}
}
P.S. and no, I didn't find the way to show alert smoothly. For this case may be better to use ZStack and change the alert (or any other view) opacity from 0 to 1 (with animation), when you tap on image.
When creating a List view onAppear triggers for elements in that list the way you would expect: As soon as you scroll to that element the onAppear triggers. However, I'm trying to implement a horizontal list like this
ScrollView(.horizontal) {
HStack(spacing: mySpacing) {
ForEach(items) { item in
MyView(item: item)
.onAppear { \\do something }
}
}
}
Using this method the onAppear triggers for all items at once, that is to say: immediately, but I want the same behavior as for a List view. How would I go about doing this? Is there a manual way to trigger onAppear, or control when views load?
Why I want to achieve this: I have made a custom Image view that loads an image from an URL only when it appears (and substitutes a placeholder in the mean time), this works fine for a List view, but I'd like it to also work for my horizontal 'list'.
As per SwiftUI 2.0 (XCode 12 beta 1) this is finally natively solved:
In a LazyHStack (or any other grid or stack with the Lazy prefix) elements will only initialise (and therefore trigger onAppear) when they appear on screen.
Here is possible approach how to do this (tested/worked with Xcode 11.2 / iOS 13.2)
Demo: (just show dynamically first & last visible cell in scrollview)
A couple of important View extensions
extension View {
func rectReader(_ binding: Binding<CGRect>, in space: CoordinateSpace) -> some View {
self.background(GeometryReader { (geometry) -> AnyView in
let rect = geometry.frame(in: space)
DispatchQueue.main.async {
binding.wrappedValue = rect
}
return AnyView(Rectangle().fill(Color.clear))
})
}
}
extension View {
func ifVisible(in rect: CGRect, in space: CoordinateSpace, execute: #escaping (CGRect) -> Void) -> some View {
self.background(GeometryReader { (geometry) -> AnyView in
let frame = geometry.frame(in: space)
if frame.intersects(rect) {
execute(frame)
}
return AnyView(Rectangle().fill(Color.clear))
})
}
}
And a demo view of how to use them with cell views being in scroll view
struct TestScrollViewOnVisible: View {
#State private var firstVisible: Int = 0
#State private var lastVisible: Int = 0
#State private var visibleRect: CGRect = .zero
var body: some View {
VStack {
HStack {
Text("<< \(firstVisible)")
Spacer()
Text("\(lastVisible) >> ")
}
Divider()
band()
}
}
func band() -> some View {
ScrollView(.horizontal) {
HStack(spacing: 10) {
ForEach(0..<50) { i in
self.cell(for: i)
.ifVisible(in: self.visibleRect, in: .named("my")) { rect in
print(">> become visible [\(i)]")
// do anything needed with visible rects, below is simple example
// (w/o taking into account spacing)
if rect.minX <= self.visibleRect.minX && self.firstVisible != i {
DispatchQueue.main.async {
self.firstVisible = i
}
} else
if rect.maxX >= self.visibleRect.maxX && self.lastVisible != i {
DispatchQueue.main.async {
self.lastVisible = i
}
}
}
}
}
}
.coordinateSpace(name: "my")
.rectReader(self.$visibleRect, in: .named("my"))
}
func cell(for idx: Int) -> some View {
RoundedRectangle(cornerRadius: 10)
.fill(Color.yellow)
.frame(width: 80, height: 60)
.overlay(Text("\(idx)"))
}
}
I believe what you want to achieve can be done with LazyHStack.
ScrollView {
LazyVStack {
ForEach(1...100, id: \.self) { value in
Text("Row \(value)")
.onAppear {
// Write your code for onAppear here.
}
}
}
}