NetNewsWire/iOS/Article/ArticleExtractorButton.swift

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Swift
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2019-09-24 23:34:11 +02:00
//
// ArticleExtractorButton.swift
// NetNewsWire-iOS
//
// Created by Maurice Parker on 9/24/19.
// Copyright © 2019 Ranchero Software. All rights reserved.
//
import UIKit
enum ArticleExtractorButtonState {
case error
case animated
case on
case off
}
class ArticleExtractorButton: UIButton {
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var buttonState: ArticleExtractorButtonState = .off {
didSet {
if buttonState != oldValue {
switch buttonState {
case .error:
stripSublayer()
setImage(AppAssets.articleExtractorError, for: .normal)
case .animated:
setImage(nil, for: .normal)
setNeedsLayout()
case .on:
stripSublayer()
setImage(AppAssets.articleExtractorOn, for: .normal)
case .off:
stripSublayer()
setImage(AppAssets.articleExtractorOff, for: .normal)
}
}
}
}
override var accessibilityLabel: String? {
get {
switch buttonState {
case .error:
return NSLocalizedString("Error - Reader View", comment: "Error - Reader View")
case .animated:
return NSLocalizedString("Processing - Reader View", comment: "Processing - Reader View")
case .on:
return NSLocalizedString("Selected - Reader View", comment: "Selected - Reader View")
case .off:
return NSLocalizedString("Reader View", comment: "Reader View")
}
}
set {
super.accessibilityLabel = newValue
}
}
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override func layoutSubviews() {
super.layoutSubviews()
guard case .animated = buttonState else {
return
}
stripSublayer()
addAnimatedSublayer(to: layer)
}
private func stripSublayer() {
if layer.sublayers?.count ?? 0 > 1 {
layer.sublayers?.last?.removeFromSuperlayer()
}
}
private func addAnimatedSublayer(to hostedLayer: CALayer) {
let image1 = AppAssets.articleExtractorOffTinted.cgImage!
let image2 = AppAssets.articleExtractorOnTinted.cgImage!
let images = [image1, image2, image1]
let imageLayer = CALayer()
let imageSize = AppAssets.articleExtractorOff.size
imageLayer.bounds = CGRect(x: 0, y: 0, width: imageSize.width, height: imageSize.height)
imageLayer.position = CGPoint(x: bounds.midX, y: bounds.midY)
hostedLayer.addSublayer(imageLayer)
let animation = CAKeyframeAnimation(keyPath: "contents")
animation.calculationMode = CAAnimationCalculationMode.linear
animation.keyTimes = [0, 0.5, 1]
animation.duration = 2
animation.values = images as [Any]
animation.repeatCount = HUGE
imageLayer.add(animation, forKey: "contents")
}
}