如何向DispatchQueue添加时间延迟变量[重复]

Question

这个问题在这里已有答案：

• Delay using DispatchTime.now() + float? 3回答

首先，我使用arc4random创建了一个randomDelay值

然后我想将randomDelay值添加到DispatchQueue以创建随机时间延迟变量

这是我的代码：

func animation1() {

UIView.animate(withDuration: 1, animations: {

    // various code

}, completion: { (true) in

    //delay calling the function by the randomDelay value of '0' to '2' seconds
    let randomDelay = arc4random_uniform(3)
    DispatchQueue.main.asyncAfter(deadline: .now() + randomDelay) { // the randomDelay value throws an unresolved identifier 'randomDelay' error
        self.showAnimation2() // Go to the next function
    }
  })
}

谢谢

Answer 1

你需要将randomDelay施放到Double。然后你按如下方式使用它：

let randomDelay = arc4random_uniform(3)
DispatchQueue.main.asyncAfter(deadline: .now() + Double(randomDelay)) {
}

Answer 2

我想这会对你有所帮助！

let aRandomVar = 2   // change 2 to desired number of seconds
 let when = DispatchTime.now() + Double(aRandomVar)
    DispatchQueue.main.asyncAfter(deadline: when) {
       // Your code with delay
    }

Answer 3

你没有提到随机数是什么时间单位。我建议你选择一个单位。例如，秒：

DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(Int(randomDelay)), execute: {...})

或毫秒：

DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(Int(randomDelay)), execute: {...})