使用按钮停止动画正方形

Question

我试图用一个按钮停止一个在视图中上下动画的方形(在循环中上下)并读取位置(x,y)这是该动作的代码

override func viewDidLoad() {
    super.viewDidLoad()

    while buttonPress == false {
    movement()
    }
}

func movement() {
    coloredSquare.backgroundColor = UIColor.blueColor()
    coloredSquare.frame = CGRect(x:0, y:500, width:50, height:50)
    self.view.addSubview(coloredSquare)
    movementDown()
}

func movementDown() {
    // lets set the duration to 1.0 seconds
    // and in the animations block change the background color
    // to red and the x-position  of the frame
    UIView.animateWithDuration(1.0, animations: {
        self.coloredSquare.backgroundColor = UIColor.blueColor()
        self.coloredSquare.frame = CGRect(x: 0, y: 500, width: 50, height: 50)
        }, completion: { animationFinished in
            self.movementUp()
    })
}

func movementUp() {
    UIView.animateWithDuration(1.0, animations: {
        self.coloredSquare.backgroundColor = UIColor.redColor()
        self.coloredSquare.frame = CGRect(x: 0, y: 0, width: 50, height: 50)
        }, completion: { animationFinished in
            self.movementDown()
    })
}

如果我尝试使用WHILE做一个方法,直到条件为假,Xcode构建但模拟器停在启动屏幕,如果我取消while条件,动画工作但没有什么能阻止它...任何人都可以帮助我吗？谢谢

Answer 1

首先,摆脱while循环.在动画完成块,首先检查如果调用其他动画之前,动画完成 - 如果你取消了动画,也不会是真实的,所以动画将停止.在您的按钮方法中,您需要访问coloredSquare的表示层以获取其当前位置,并取消所有动画以使动画立即停止.

class ViewController: UIViewController {

var coloredSquare: UIView = UIView()

override func viewDidLoad() {
    super.viewDidLoad()
    [self .movement()];
}


func movement() {

    coloredSquare.backgroundColor = UIColor.blueColor()

    coloredSquare.frame = CGRect(x:0, y:500, width:50, height:50)

    self.view.addSubview(coloredSquare)

    movementDown()
}

func movementDown() {

    UIView.animateWithDuration(3.0, animations: {
        self.coloredSquare.backgroundColor = UIColor.blueColor()
        self.coloredSquare.frame = CGRect(x: 0, y: 500, width: 50, height: 50)
        }, completion: { animationFinished in
            if animationFinished {
                self.movementUp()
            }
    })
}

func movementUp() {
    UIView.animateWithDuration(3.0, animations: {
        self.coloredSquare.backgroundColor = UIColor.redColor()
        self.coloredSquare.frame = CGRect(x: 0, y: 0, width: 50, height: 50)
        }, completion: { animationFinished in
            if animationFinished {
                self.movementDown()
            }
    })
}



@IBAction func stopBlock(sender: AnyObject) {
    var layer = coloredSquare.layer.presentationLayer() as CALayer
    var frame = layer.frame
    println(frame)
    coloredSquare.layer.removeAllAnimations()
    coloredSquare.frame = frame // You need this to keep the block where it was when you cancelled the animation, otherwise it will jump to the position defined by the end of the current animation
}

}