UIAnimation repeating issue in Swift

问题

I have a simple UIButton in my project with animation block running inside the button. Basically, I have a mainButton that connected to two other sub Buttons. When mainButton is pressed, my subButtons will appear to the view with animation. I am using the following code.

@IBOutlet weak var mainButton: UIButton!
@IBOutlet weak var subButton1: UIButton!
@IBOutlet weak var subButton2: UIButton!

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

     subButton1.hidden = true
     subButton2.hidden = true
}

 //    override func viewDidAppear(animated: Bool) {
 //        subButton1.hidden = true
 //        subButton2.hidden = true
 //    }

@IBAction func mainButtonAction(sender: AnyObject) {

     self.subButton1.hidden = false
     self.subButton2.hidden = false

     self.subButton1.center.x += self.view.frame.width
     self.subButton2.center.x -= self.view.frame.width

     //First Piece of Animation:
     UIView.animateWithDuration(1.5, delay: 0.05,usingSpringWithDamping: 0.9,initialSpringVelocity: 0.5, options:UIViewAnimationOptions.CurveEaseIn, animations: {

     self.subButton1.center.x -= self.view.frame.width
     self.subButton2.center.x += self.view.frame.width

        }, completion: {finished in 

      //Second Piece of Animation:       
     UIView.animateWithDuration(1.5, delay: 5, options:UIViewAnimationOptions.CurveEaseOut, animations: {

     self.subButton1.center.x += self.view.frame.width 
     self.subButton2.center.x -= self.view.frame.width

     }, completion:  nil)
     })
     }

Above code works as I want it to work but only when I press the mainButton for the first time. But, the problem is that nothing happens when I press the mainButton again. I want the animation to occur every time when the mainButton is pressed....

Thanks in Advance.

回答1:

You are having an issue with the animation timing for appearing and disappearing. Both portions of animation are working fine. If you click the button ahead of time, you are having issues with the X location of the button. Notice that if you comment on of "pieces of animation" your code works fine. You can print the X values and see what is happening.

Few options:

Toggle between the two.

Create a starting point, and when the button is pressed:

class ViewController: UIViewController {

var intialPointXButton1: CGFloat = 0.0
var intialPointXButton2: CGFloat = 0.0
...

Disable the button while the animation is running:

@IBAction func mainButtonAction(sender: AnyObject) {

  self.subButton1.hidden = false
  self.subButton2.hidden = false

  self.subButton1.center.x += self.view.frame.width
  self.subButton2.center.x -= self.view.frame.width
  self.mainButton.enabled = false // Disable the main button

  //First Piece of Animation:
  UIView.animateWithDuration(1.5, delay: 0.05,usingSpringWithDamping: 0.9,initialSpringVelocity: 0.5, options:UIViewAnimationOptions.CurveEaseIn, animations: {

  self.subButton1.center.x -= self.view.frame.width
  self.subButton2.center.x += self.view.frame.width

  }, completion: {finished in

    //Second Piece of Animation:
    UIView.animateWithDuration(1.5, delay: 5, options:UIViewAnimationOptions.CurveEaseOut, animations: {

      self.subButton1.center.x += self.view.frame.width
      self.subButton2.center.x -= self.view.frame.width

      }, completion:  { finished in
        self.mainButton.enabled = true // Enable the main button
    })
  })
}

来源：https://stackoverflow.com/questions/37453328/uianimation-repeating-issue-in-swift

标签

swift

uiviewanimation