如何在20秒后使用swift制作动画? animateWithDuration:delay:没有用 [英] How to do animation in 20 seconds later using swift? animateWithDuration:delay: is useless

问题描述

UIView.animateWithDuration(10, delay: 20, options: .TransitionNone, animations: {

    }) { (let finish) in
        print("finish")
    }

就像显示的代码一样，我想在20秒后打印完成"，但是我会立即得到它.

Like the code shown, i want to print "finish" after 20 seconds, however i get it immediately.

顺便问一下，有多少种方法会使操作延迟?

By the way, how many ways to do make operations delay?

推荐答案

第一种方法:NSTimer

First Method: NSTimer

func myDelayedFunction() {
    print("delayed")
}

func myMainFunction() {
    let timer = NSTimer.scheduledTimerWithTimeInterval(10, target: self, selector: "myDelayedFunction", userInfo: nil, repeats: false)
    timer.fire()
}

第二种方法:performSelector

Second Method: performSelector

func myDelayedFunction() {
    print("delayed")
}

func myMainFunction() {
    performSelector("myDelayedFunction", withObject: self, afterDelay: 10)
}

第三种方法:GCD(如果要使用匿名函数，则很有用) (改编自此答案)

Third Method: GCD (useful if you want an anonymous function) (adapted from this answer)

let delayInSeconds: Int64 = 3
let popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * Int64(NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue()) {
    print("Delayed") 
}

第四种方法:sleep

Fourth Method: sleep

func myMainFunction() {
    sleep(10) //This will block whichever thread you're running on.
    print("delayed")
}

我倾向于使用第一种方法，因为如果需要，我总是可以使计时器无效(调用timer.invalidate).不过，每种方法都有其用例.

I tend to use the first method, because I can always invalidate the timer if I need to (calling timer.invalidate). Each method has its use case, though.

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