animateWithDuration 缺少完成块，WatchOS 2

Question

watchOS 2 在其 animateWithDuration 函数中没有任何类型的完成块。我正在开发一个需要在动画完成后运行代码的游戏。有解决办法吗？也许使用键值观察？另一种方法是使用与动画长度相匹配的计时器，但由于显而易见的原因，这并不理想。

Answer 1

NSOperation 对我也不起作用。我现在只是使用以下解决方案，直到 Apple 正式添加完成块。不理想，但它有效。我打开了雷达。也许 Apple 会在 watchOS 2 的未来种子中添加一个完成块。

此扩展添加了一个采用完成块的 animateWithDuration 方法。并且在动画块的持续时间之后调用完成块。

extension WKInterfaceController {
    func animateWithDuration(duration: NSTimeInterval, animations: () -> Void, completion: (() -> Void)?) {
        animateWithDuration(duration, animations: animations)
        let completionDelay = dispatch_time(DISPATCH_TIME_NOW, Int64(duration * Double(NSEC_PER_SEC)))
        dispatch_after(completionDelay, dispatch_get_main_queue()) {
            completion?()
        }
    }
}

Answer 2

尝试使用 WKInterfaceController 中的完成块扩展 animateWithDuration 方法

Obj-C 版本（感谢@PunnetSethi）：

- (void)animateWithDuration:(NSTimeInterval)duration animations:(void (^)(void))animations completion:(void (^)(void))completion{

    [self animateWithDuration:duration animations:animations];

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(duration * NSEC_PER_SEC)), dispatch_get_main_queue(), completion);

}

使用 WatchOS2 处理真正的 Watch

Answer 3

斯威夫特 4

watchOS的

高级animate()方法：

• 可重复
• 可逆
• 可停止
• 带有完成块

---

import Foundation
import WatchKit



protocol Animatable: class {

func animate(forKey key: String,duration: TimeInterval, repeatCount count: CGFloat, autoreverses: Bool, animations: @escaping () -> Void, reverseAnimations: (() -> Void)?, completion: (() -> Void)?)
func stopAnimations()
}

extension Animatable {

func animate(forKey key: String, duration: TimeInterval, repeatCount count: CGFloat, autoreverses: Bool, animations: @escaping () -> Void, reverseAnimations: (() -> Void)?, completion: (() -> Void)?) {}

func stopAnimations() {}
}

extension WKInterfaceController: Animatable {

private struct AssociatedKeys {
    static var animsDesc = "_animsDesc"
    static var stopDesc = "_stopDesc"
}

var animations: [String: (() -> Void)?] {
    get {return objc_getAssociatedObject(self, &AssociatedKeys.animsDesc) as? [String: (() -> Void)?] ?? [:]}
    set {objc_setAssociatedObject(self, &AssociatedKeys.animsDesc, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)}
}

var animationStopStates: [String: Bool] {
    get {return objc_getAssociatedObject(self, &AssociatedKeys.stopDesc) as? [String: Bool] ?? [:]}
    set {objc_setAssociatedObject(self, &AssociatedKeys.stopDesc, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)}
}

func animate(forKey key: String, duration: TimeInterval, repeatCount count: CGFloat = 1.0, autoreverses: Bool = false, animations: @escaping () -> Void, reverseAnimations: (() -> Void)? = nil, completion: (() -> Void)? = nil) {
    let isStopped = self.animationStopStates[key] ?? false
    if isStopped {
        completion?()
        return
    }
    self.setAnimations(key, reverse: reverseAnimations)
    let count = count - 1
    let deadline = DispatchTime.now() + duration
    self.animate(withDuration: duration, animations: animations)
    DispatchQueue.main.asyncAfter(deadline: deadline) {
        var deadline2 = DispatchTime.now()
        if autoreverses, let rev = reverseAnimations {
            self.animate(withDuration: duration, animations: rev)
            deadline2 = DispatchTime.now() + duration
        }
        DispatchQueue.main.asyncAfter(deadline: deadline2, execute: {
            if !count.isEqual(to: .infinity) && count <= 0 {
                completion?()
            } else {
                self.animate(forKey: key, duration: duration, repeatCount: CGFloat(count), autoreverses: autoreverses, animations: animations, reverseAnimations: reverseAnimations, completion: completion)
            }
        })
    }
}


/// Stops all the currently playing animations
func stopAnimations() {
    for key in self.animations.keys {
        guard let rev = self.animations[key] else {return}
        self.animationStopStates[key] = true
        self.animate(forKey: key, duration: 0, repeatCount: 0, autoreverses: false, animations: {}, reverseAnimations: rev)
    }
    self.animations.removeAll()
}


private func setAnimations(_ key: String, reverse: (() -> Void)?) {
    if self.animations[key] == nil {
        self.animations[key] = reverse
    }

}
}

---

使用方法：

self.animate(forKey: "custom_anim1", duration: 1.0, repeatCount: .infinity, autoreverses: true, animations: {[unowned self] in
        self.myButton.setHeight(100)
    }, reverseAnimations: { [unowned self] in
        self.myButton.setHeight(120)
    }) {
        print("Animation stopped!")
    }

停止所有动画：

self.stopAnimations()

Answer 4

您可以使用此扩展程序。这是一个更好的解决方案，因为它不依赖于时间，例如在与动画延迟相同的时间后调度代码块。而且很优雅。

extension WKInterfaceController {
    func animate(withDuration duration: TimeInterval,
                 animations: @escaping () -> Swift.Void,
                 completion: @escaping () -> Swift.Void) {

        let queue = DispatchGroup()
        queue.enter()

        let action = {
            animations()
            queue.leave()
        }

        self.animate(withDuration: duration, animations: action)

        queue.notify(queue: .main, execute: completion)
    }
}

您可以像这样轻松使用它：

self.animate(withDuration: 0.2, animations: {
    //your animation code
}, completion: {
    //to do after you animation 
})