Question

我试图延迟不到一秒钟。我从网上找到了这段代码。然而，它不接受不到一秒的延迟。 Swift中的Grand Dispatch Concept对我来说有点神秘。我应该如何修改此代码以创建0.3秒的延迟？

    let deadlineTime = DispatchTime.now() + .seconds(1) //how to get 0.3 seconds here
    DispatchQueue.main.asyncAfter(deadline: deadlineTime) {        
      //code here
    }

Answer 1

嗯，这很简单，不用秒，使用毫秒：

let deadlineTime = DispatchTime.now() + .milliseconds(300) // 0.3 seconds

Answer 2

只需将您需要的时间添加到DispatchTime.now()，您就会得到一个结果

let deadlineTime = DispatchTime.now() + 0.3 //Here is 0.3 second as per your requirement 
    DispatchQueue.main.asyncAfter(deadline: deadlineTime) {        
      //code here
    }

Answer 3

DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) { 
     // your method after delay
}

请记住，这将在主线程上执行。如果您不想要，请选中DispatchQueue.global(qos:)或this reference

Answer 4

使用它，将起作用

let delay = 2.5 * Double(NSEC_PER_SEC) 
let time = DispatchTime.now() + Double(Int64(delay)) / Double(NSEC_PER_SEC)  

DispatchQueue.main.asyncAfter(deadline: time, execute: {
     self.view_Alert.alpha = 0 
})

Swift 3.0：延迟不到一秒钟

4 个答案: