Question

我正在尝试将其在故事板上的位置向上移动100px。

如果随机生成的数字为1，则标签会更改为表示尚未获胜。

如果随机生成的数字是2，则标签会改变，表示他们已经赢了一个镜头。

我使用以下代码：

./true

我发现有时当我摇动设备时，动画开始于原始位置以下100px并移回原位置，有时它会从最后位置向上移动100px。

如何确保它始终从故事板上的原始位置移动？

Answer 1

确保某些内容位于同一位置的最佳方法是在Main.storyboard文件中为其提供约束（首先要做的事情）。另外，作为额外的预防措施，您可以在viewDidLoad中阅读其帧值并在motionEnded中重新设置。

var stampFrame : CGRect = CGRect(x: 0, y: 0, width: 0, height: 0) // This is stampFrame's initial value before being set in viewDidLoad

override func viewDidLoad() {
    super.viewDidLoad()
    stampFrame = stampView.frame // Here we store the frame value for usage later
    // If you would like, you can also set this in a method like viewWillAppear or viewDidAppear, but I'd just keep it in viewDidLoad
}


override func motionEnded(motion: UIEventSubtype, withEvent event: UIEvent?) {

    stampView.frame = stampFrame 

    if motion == .MotionShake{

       let randomNumber = arc4random_uniform(2) + 1

        print(randomNumber)

        if randomNumber == 1 {

            labelOne.text = "Sorry!"
            labelTwo.text = "You Have Not Won This Time"
            labelThree.text = "Better Luck Tomorrow"

        }

        if randomNumber == 2 {

            labelOne.text = "Winner!"
            labelTwo.text = "1 x Shot Patron Cafe"
            labelThree.text = "Show at the bar to claim."

        }

     //   let xPosition = stampView.frame.origin.x

     //   View will slide 20px up
     //   let yPosition = stampView.frame.origin.y - 100

     //   let height = stampView.frame.size.height
     //   let width = stampView.frame.size.width
     // The code above is redundant, we can just do it all in the UIView.animate 

        UIView.animate(withDuration: 3.0, animations: {

            self.stampView.frame.origin.y -= 100
     // This moves stampView's position up 100pts from its current location


        })


        print("SHAKEN!")

    }

好吧无论如何，我希望如果您有任何疑问，请帮助您，欢迎您的询问。

非常基本的Swift动画

1 个答案: