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@romiroma
Created October 31, 2020 06:06
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Tappable Text in SwiftUI
import Foundation
import SwiftUI
struct TappableColoredText: View {
enum Component {
case text(String)
case tappable(String, () -> Void)
}
let components: [Component]
let font: UIFont
init(
text: String,
tappables: [Range<String.Index>: () -> Void],
font: UIFont
) {
var components: [Component] = []
var index: String.Index = text.startIndex
let sortedTappables = tappables.sorted {
$0.key.lowerBound < $1.key.lowerBound
}
for tappable in sortedTappables {
if tappable.key.lowerBound > index {
let textRange: Range<String.Index> = index..<tappable.key.lowerBound
let textSubstring = String(text[textRange])
components.append(.text(textSubstring))
}
let substring = String(text[tappable.key])
components.append(.tappable(substring, tappable.value))
index = tappable.key.upperBound
}
if index < text.indices.endIndex {
let textRange = index..<text.indices.endIndex
let substring = String(text[textRange])
components.append(.text(substring))
}
self.components = components
self.font = font
}
var body: some View {
components.map { component in
switch component {
case .text(let text):
return SwiftUI.Text(verbatim: text)
.foregroundColor(SwiftUI.Color.white.opacity(0.6))
case .tappable(let text, _):
return SwiftUI.Text(verbatim: text)
.foregroundColor(.white)
}
}
.reduce(SwiftUI.Text(""), +)
.font(.init(self.font))
}
}
struct TappableText: View {
let text: String
let tappables: [String: () -> Void]
let matches: [Range<String.Index>: () -> Void]
let font: UIFont
init(
text: String,
tappables: [String: () -> Void],
font: UIFont
) {
self.text = text
self.tappables = tappables
var ranges: [Range<String.Index>: () -> Void] = [:]
for tappable in tappables {
guard let range = text.range(of: tappable.key) else {
continue
}
ranges[range] = tappable.value
}
matches = ranges
self.font = font
}
var body: some View {
TappableColoredText(text: text, tappables: matches, font: self.font)
.overlay(LinkTapOverlay(text: text, tappables: matches, font: font))
}
}
private struct LinkTapOverlay: UIViewRepresentable {
let text: String
let tappables: [Range<String.Index>: () -> Void]
let font: UIFont
func makeUIView(context: Context) -> LinkTapOverlayView {
let view = LinkTapOverlayView()
view.textContainer = context.coordinator.textContainer
view.isUserInteractionEnabled = true
let tapGesture = UITapGestureRecognizer(target: context.coordinator, action: #selector(Coordinator.didTapLabel(_:)))
tapGesture.delegate = context.coordinator
view.addGestureRecognizer(tapGesture)
return view
}
func updateUIView(_ uiView: LinkTapOverlayView, context: Context) {
let attributedString = NSAttributedString(string: text, attributes: [.font: font])
context.coordinator.textStorage = NSTextStorage(attributedString: attributedString)
context.coordinator.textStorage!.addLayoutManager(context.coordinator.layoutManager)
}
func makeCoordinator() -> Coordinator {
Coordinator(self)
}
class Coordinator: NSObject, UIGestureRecognizerDelegate {
let overlay: LinkTapOverlay
let layoutManager = NSLayoutManager()
let textContainer = NSTextContainer(size: .zero)
var textStorage: NSTextStorage?
init(_ overlay: LinkTapOverlay) {
self.overlay = overlay
textContainer.lineFragmentPadding = 0
textContainer.lineBreakMode = .byWordWrapping
textContainer.maximumNumberOfLines = 0
layoutManager.addTextContainer(textContainer)
}
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
let location = touch.location(in: gestureRecognizer.view!)
let result = tappable(at: location)
return result != nil
}
@objc func didTapLabel(_ gesture: UITapGestureRecognizer) {
let location = gesture.location(in: gesture.view!)
guard let result = tappable(at: location) else {
return
}
result()
}
private func tappable(at point: CGPoint) -> (() -> Void)? {
guard !overlay.tappables.isEmpty else {
return nil
}
let indexOfCharacter = layoutManager.characterIndex(
for: point,
in: textContainer,
fractionOfDistanceBetweenInsertionPoints: nil
)
let text = overlay.text
let stringIndex = text.index(text.startIndex, offsetBy: indexOfCharacter)
return overlay.tappables.first(where: { (tappable) -> Bool in
tappable.key.contains(stringIndex)
})?.value
}
}
}
private class LinkTapOverlayView: UIView {
var textContainer: NSTextContainer!
override func layoutSubviews() {
super.layoutSubviews()
textContainer.size = bounds.size
}
}
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