编辑代码

var myString = "Hello world!     -  swift.jsrun.net"
print(myString)
let iv = self.view.viewWithTag(4)!
UIView.animate(withDuration: 2, anmations: {
    iv.transform = iv.transform.rotated(by: CGFloat(360))
})



let iv = self.view.viewWithTag(4)!
UIView.animate(withDuration: 2, animations: {
    iv.frame.origin.x += 100
    if iv.frame.origin.x > self.view.frame.size.width {
        iv.frame.origin.x = 0
    }
})



let iv = self.view.viewWithTag(4)!
UIView.animate(withDuration: 2, animations: {
    iv.alpha = 0.1
})