Swift make blinking spotlight

We want to have a row of blinking spotlight.

Let make some round icons with same dimension, but different color at center.

Drag icons in to project.

The images with same dimension, so when we change them, it look like they are blinking.

Declare to above viewDidLoad.

let im1 = UIImage(named: "l1");

    let im2 = UIImage(named: "l2");

    let im3 = UIImage(named: "l3");

    let im4 = UIImage(named: "l1");

    let im5 = UIImage(named: "l2")

  

    var ima1: UIImageView!

    var ima2: UIImageView!

    var ima3: UIImageView!

    var ima4: UIImageView!;

    var ima5: UIImageView!;

var count=1

Set position, add to view inside viewDidLoad

ima1 = UIImageView(frame: CGRect(x: le, y: 520, width: 40, height: 40))

        ima2 = UIImageView(frame: CGRect(x: le+45, y: 520, width: 40, height: 40))

        ima3 = UIImageView(frame: CGRect(x: le+90, y: 520, width: 40, height: 40))

        ima4 = UIImageView(frame: CGRect(x: le+135, y: 520, width: 40, height: 40))

        ima5 = UIImageView(frame: CGRect(x: le+180, y: 520, width: 40, height: 40))

        ima1.image = im1

        ima2.image = im2

        ima3.image = im3

        ima4.image = im4

        ima5.image = im5

view.addSubview(ima1)

        view.addSubview(ima2)

        view.addSubview(ima3)

        view.addSubview(ima4)

        view.addSubview(ima5)

Variable le use to make images center screen.

We get screen width.

let r = UIScreen.mainScreen().bounds.size.width

We know images row width 220dp, we calculate margin like this.

let le = (Int(r) - 220)/2

Copy to above last close bracket.

func update(){      

       count = count + 1

        if count%3==1{

            ima1.image = im1

            ima2.image = im2

            ima3.image = im3

            ima4.image = im4

            ima5.image = im5

        }

        else if count%3==2{

            ima1.image = im2

            ima2.image = im3

            ima3.image = im4

            ima4.image = im5

            ima5.image = im1

        }

        else{

            ima1.image = im3

            ima2.image = im4

            ima3.image = im5

            ima4.image = im1

            ima5.image = im2

        }

    }

Last, add this line in to viewDidLoad.

let time=NSTimer.scheduledTimerWithTimeInterval(1.0, target:self,  selector: "update",userInfo: nil, repeats: true)

We change images follow time, there are three phases change after 1, 2, 3 second. We divide time to 3 and get remainder, use them to set if command.

This changing images make them look like blinking.