swift - 创建一个用于执行动画的等待队列

Question

我目前正在制作快速动画。此动画在不稳定的时间间隔内由另一个函数触发(连接到服务器)。动画需要 2 秒才能完成，但它有可能在完成之前被触发。这就是为什么我正在考虑创建一个等待队列来存储触发事件，直到动画完成并可以重新启动。因此，一方面我必须锁定动画功能直到它再次准备就绪，另一方面我需要同时为传入事件进行某种存储。我已经在考虑调度组，但不知道如何使用它们。如果有任何意见可以帮助我解决这个问题，我会非常高兴。

触发函数:

private func subscribeToNewBLock() {
        DispatchQueue.global(qos:.userInteractive).async {
            watchForNewBlock() {result in
                switch result {
                case .Failure:
                    return
                case .Success(let result):
                    //Animation function
                    self.moveBlocksDown(blockNumber: result)
                    //Recursive call to keep listening for new blocks
                    self.subscribeToNewBLock()
                }
            }
       }
}

Answer 1

你可以尝试像下面的例子那样制作你的动画队列

var results = [Int]()
var isAnimating = false

private func subscribeToNewBLock() {
    DispatchQueue.global(qos:.userInteractive).async {
        watchForNewBlock() {result in
            switch result {
            case .Failure:
                return
            case .Success(let result):

                //Call your UI operations in main thread
                DispatchQueue.main.async {

                    self.results.append(result)
                    //Animation function
                    self.moveBlocksDown()

                    //Recursive call to keep listening for new blocks
                    self.subscribeToNewBLock()
                }
            }
        }
    }
}

private func moveBlocksDown() {

    guard isAnimating == false && results.count > 0 else {

        return
    }

    self.moveBlocksDown(blockNumber: results.first!)

}

private func moveBlocksDown(blockNumber:Int){

    isAnimating = true

    UIView.animate(withDuration: 2.0, animations: {

        //Animation code goes here

    }) { (completed) in

        if completed{

            //Add follwing code in place of animation completed(May be in completion handler)
            self.isAnimating = false
            self.results = self.results.filter{$0 != blockNumber} //Remove already animated blockNumber
            self.moveBlocksDown() //Call moveBlocksDown function to check if anything pending in queue
        }
    }
}