快速为for循环添加延迟 [英] Add a delay to a for loop in swift

问题描述

我有一个编码问题".

我有一个标签，我想每2秒动态更改一次该文本. 我已完成以下操作:

I have a label, which text I want to change dynamically every 2 seconds. I've done the following:

// WELCOME STRING ARRAY
let welcomeContainer:[String] = ["Welcome","Benvenuti","Bienvenue","Willkommen","üdvözlet","Dobrodošli","добро пожаловать","Witajcie","Bienvenido","Ласкаво просимо","Vitajte","欢迎你来"]

，然后，而不是使用timerwithinterval(对于这个简单的任务来说似乎太多了)，我尝试在for循环中的函数中使用delay方法:

and then, rather than using a timerwithinterval (which seemed to be too much for this simple task), I tried with the delay method in my function inside for loop:

func welcomeLabelChange() {
for i in 0..<welcomeContainer.count {
    welcomeLabel.text = welcomeContainer[i]
    delay(delay: 2.0, closure: {})
}

不幸的是，它完全跳过了延迟... for循环立即执行，仅显示数组中的最后一个文本. 我在做什么错了?

Unfortunately it's entirely skipping the delay... the for loop is executed instantly and just the last text in the array is displayed. What am I doing wrong?

我找到了这个 OBJ-C答案，但是这表明(旧的)NSTimer实现.

I found this OBJ-C answer, but it's suggesting an (old) NSTimer implementation.

推荐答案

您还可以使用此功能延迟某些时间

You can also use this function to delay something

//MARK: Delay func 

func delay(_ delay:Double, closure:@escaping ()->()) {
    DispatchQueue.main.asyncAfter(
        deadline: DispatchTime.now() + Double(Int64(delay * Double(NSEC_PER_SEC))) / Double(NSEC_PER_SEC), execute: closure)
}

，用法是:

        delay(2)  //Here you put time you want to delay
{
            //your delayed code
        }

希望它会对您有所帮助.

Hope it will help you.

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