Created
January 12, 2023 19:11
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Draggable paged views where clicking the focused view triggers an action and clicking any other view scrolls to that view.
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// | |
// PagedSelectableView.swift | |
// FrameUpExample | |
// | |
// Created by Ryan Lintott on 2023-01-12. | |
// | |
import SwiftUI | |
struct PagedSelectableView: View { | |
let items = ["1","2","3","4","5"] | |
@State private var currentItemIndex: Int = 0 | |
@State private var predictedDragOffset: CGFloat = .zero | |
@State private var dragOffset: CGFloat = .zero | |
@GestureState private var isDragging: Bool = false | |
let itemWidth: CGFloat = 80 | |
@State private var lastTappedItem: String? = nil | |
var totalOffset: CGFloat { | |
(itemWidth * CGFloat(items.count) / 2) | |
- ((CGFloat(currentItemIndex) + 0.5) * itemWidth) | |
+ dragOffset | |
} | |
var drag: some Gesture { | |
DragGesture(minimumDistance: 0.001) | |
.updating($isDragging) { value, gestureState, transaction in | |
gestureState = true | |
} | |
.onChanged { value in | |
predictedDragOffset = value.predictedEndTranslation.width | |
dragOffset = value.translation.width | |
} | |
} | |
func onDragEnded() { | |
let itemDelta = Int(-predictedDragOffset / itemWidth) | |
currentItemIndex = max(items.startIndex, min(currentItemIndex + itemDelta, items.count - 1)) | |
dragOffset = .zero | |
predictedDragOffset = .zero | |
} | |
var enumeratedItems: Array<(String,Int)> { | |
Array(zip(items, items.indices)) | |
} | |
var body: some View { | |
VStack { | |
HStack(spacing: 0) { | |
ForEach(enumeratedItems, id: \.0) { (item, index) in | |
Circle() | |
.fill(Color.blue) | |
.overlay(Text("\(item)")) | |
.foregroundColor(.white) | |
.aspectRatio(1, contentMode: .fit) | |
.padding(3) | |
.frame(width: itemWidth) | |
.onTapGesture { | |
if isDragging { return } | |
if index == currentItemIndex { | |
lastTappedItem = item | |
} else { | |
currentItemIndex = index | |
} | |
} | |
} | |
} | |
.animation(.spring(), value: totalOffset) | |
.fixedSize(horizontal: true, vertical: false) | |
.offset(x: totalOffset) | |
.simultaneousGesture(drag) | |
.background( | |
Circle() | |
.stroke(lineWidth: 3) | |
.aspectRatio(1, contentMode: .fit) | |
.frame(width: itemWidth + 20) | |
.foregroundColor(.red) | |
) | |
.onChange(of: isDragging) { isDragging in | |
if !isDragging { onDragEnded() } | |
} | |
Text("Last Red Item Tapped: \(lastTappedItem ?? "nil")") | |
// Text("currentItemIndex: \(currentItemIndex)") | |
// Text("dragOffset: \(dragOffset)") | |
// Text("predictedDragOffset: \(predictedDragOffset)") | |
} | |
} | |
} | |
struct PagedSelectableView_Previews: PreviewProvider { | |
static var previews: some View { | |
PagedSelectableView() | |
} | |
} |
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