Swift ios date as milliseconds Double or UInt64?

Question

I'm not iOS developer but started learning Swift.

I try to convert some logic from Android project to iOS.

I have the following method:

func addGroupItemSample(sample : WmGroupItemSample){ // some custom class

    var seconds: NSTimeInterval = NSDate().timeIntervalSince1970
    var  cuttDate:Double =  seconds*1000;

    var sampleDate: UInt64 = sample.getStartDate(); // <-- problematic place

if(sampleDate > cuttDate){
   // ....
  }
}

From the method above you can see that sample.getStartDate() returns type UInt64.

I thought it's like long in Java: System.currentTimeMillis()

But current time in milliseconds defined as Double.

Is it a proper way to mix Double and UInt64 or do I need to represent all milliseconds as Double only?

Thanks,

Answer 1

in iOS it is better to use double, but if you want to easy port your code and keep it consistent you can try this:

func currentTimeMillis() -> Int64{
    let nowDouble = NSDate().timeIntervalSince1970
    return Int64(nowDouble*1000)
}

Answer 2

Swift does not allow comparing different types.

seconds is a Double floating point value in seconds with sub-second accuracy.
sampleDate is a UInt64 but the units are not given. sampleDate needs be converted to a Double floating point value with units of seconds.

var sampleDate: Double = Double(sample.getStartDate())

Then they can be compared:

if(sampleDate > cuttDate){}