Implementing a delay in Swift

This is a simple post: we often need  delay in our software, so how to do that in Swift now dispatch_after has been changed beyond recognition?

There are multiple possibilities: use the "Thread.sleep" or use a timer instance are two of the often used. But both have drawbacks, the 'sleep' statement delays the actual thread that our code is running on, which degrades performance. And using (NS) Timer is too complex.

When I first looked at DispatchQueue.asyncAfter I hit a brick wall with doing arithmetic on DispatchTime or DispatchWallTime.

A second look at the Dispatch class showed the proper way to do this: simply add the delay not as a double but as a DispatchTimeInterval.

This code is so easy, it does not even need a wrapper:

        DispatchQueue.main.asyncAfter(

            deadline: DispatchTime.now() + DispatchTimeInterval.milliseconds(250),

            execute: {

                ...

            }

        )

Or even simpler:

        DispatchQueue.main.asyncAfter(

            deadline: .now() + .milliseconds(250),

            execute: {

                ...

            }

        )

Instead of milliseconds we can also choose from seconds, microseconds or even nanoseconds.

Happy coding...

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