I want to create an animating image slider with indicator. My code as follow:
ScrollView(.horizontal, showsIndicators: true) {
HStack {
Image(shelter.background)
.resizable()
.frame(width: UIScreen.main.bounds.width, height: 300)
Image("pacific")
.resizable()
.frame(width: UIScreen.main.bounds.width, height: 300)
}
}
I want it a little different (similar to a PageViewController in UIKit). And behave like the typical image slider we know from a lot of apps with indicator. Is there any good method?
Please use my code.
struct PagingView<Content>: View where Content: View {
@Binding var index: Int
let maxIndex: Int
let content: () -> Content
@State private var offset = CGFloat.zero
@State private var dragging = false
init(index: Binding<Int>, maxIndex: Int, @ViewBuilder content: @escaping () -> Content) {
self._index = index
self.maxIndex = maxIndex
self.content = content
}
var body: some View {
ZStack(alignment: .bottomTrailing) {
GeometryReader { geometry in
ScrollView(.horizontal, showsIndicators: false) {
HStack(spacing: 0) {
self.content()
.frame(width: geometry.size.width, height: geometry.size.height)
.clipped()
}
}
.content.offset(x: self.offset(in: geometry), y: 0)
.frame(width: geometry.size.width, alignment: .leading)
.gesture(
DragGesture().onChanged { value in
self.dragging = true
self.offset = -CGFloat(self.index) * geometry.size.width + value.translation.width
}
.onEnded { value in
let predictedEndOffset = -CGFloat(self.index) * geometry.size.width + value.predictedEndTranslation.width
let predictedIndex = Int(round(predictedEndOffset / -geometry.size.width))
self.index = self.clampedIndex(from: predictedIndex)
withAnimation(.easeOut) {
self.dragging = false
}
}
)
}
.clipped()
PageControl(index: $index, maxIndex: maxIndex)
}
}
func offset(in geometry: GeometryProxy) -> CGFloat {
if self.dragging {
return max(min(self.offset, 0), -CGFloat(self.maxIndex) * geometry.size.width)
} else {
return -CGFloat(self.index) * geometry.size.width
}
}
func clampedIndex(from predictedIndex: Int) -> Int {
let newIndex = min(max(predictedIndex, self.index - 1), self.index + 1)
guard newIndex >= 0 else { return 0 }
guard newIndex <= maxIndex else { return maxIndex }
return newIndex
}
}
struct PageControl: View {
@Binding var index: Int
let maxIndex: Int
var body: some View {
HStack(spacing: 8) {
ForEach(0...maxIndex, id: \.self) { index in
Circle()
.fill(index == self.index ? Color.white : Color.gray)
.frame(width: 8, height: 8)
}
}
.padding(15)
}
}
And demo code:
struct ContentView: View {
@State var index = 0
var images = ["10-12", "10-13", "10-14", "10-15"]
var body: some View {
VStack(spacing: 20) {
PagingView(index: $index.animation(), maxIndex: images.count - 1) {
ForEach(self.images, id: \.self) { imageName in
Image(imageName)
.resizable()
.scaledToFill()
}
}
.aspectRatio(4/3, contentMode: .fit)
.clipShape(RoundedRectangle(cornerRadius: 15))
PagingView(index: $index.animation(), maxIndex: images.count - 1) {
ForEach(self.images, id: \.self) { imageName in
Image(imageName)
.resizable()
.scaledToFill()
}
}
.aspectRatio(3/4, contentMode: .fit)
.clipShape(RoundedRectangle(cornerRadius: 15))
Stepper("Index: \(index)", value: $index.animation(.easeInOut), in: 0...images.count-1)
.font(Font.body.monospacedDigit())
}
.padding()
}
}
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