Swift:animateWithDuration行为

时间:2016-08-04 19:21:15

标签: ios swift animation

我已经制作了简单的文字和按钮动画,从屏幕出来到屏幕中间,但事实并非如此。它从屏幕进入屏幕。基本上,动画是相反的。

我已经看到其他应用程序按照我不会使用相同代码的方式工作,所以我不知道出了什么问题。 :(

以下是代码:

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var welcomeText: UILabel!
@IBOutlet weak var worksText: UILabel!
@IBOutlet weak var loginButton: UIButton!
@IBOutlet weak var signUp: UIButton!
@IBOutlet weak var socialLog: UILabel!

override func viewDidLoad() {
    super.viewDidLoad()

}

override func viewWillAppear(animated: Bool) {

    welcomeText.alpha = 0.0
    worksText.alpha = 0.0
    loginButton.alpha = 0.0
    signUp.alpha = 0.0
    socialLog.alpha = 0.0

    welcomeText.center.x -= view.bounds.width
    worksText.center.x -= view.bounds.width
    socialLog.center.x -= view.bounds.width
    signUp.center.x -= view.bounds.width
}

override func viewDidAppear(animated: Bool) {

    self.welcomeText.fadeIn()
    UIView.animateWithDuration(0.7, delay: 0.1, options: .CurveEaseOut, animations: {
        self.welcomeText.center.x += self.view.bounds.width
        self.view.layoutIfNeeded()
        }, completion: nil)

    self.worksText.fadeIn()
    UIView.animateWithDuration(0.7, delay: 0.5, options: .CurveEaseOut, animations: {
        self.worksText.center.x += self.view.bounds.width
        self.view.layoutIfNeeded()
        }, completion: nil)

    self.socialLog.fadeIn()
    UIView.animateWithDuration(0.7, delay: 0.3, options: .CurveEaseOut, animations: {
        self.socialLog.center.x += self.view.bounds.width
        self.view.layoutIfNeeded()
        }, completion: nil)

    self.signUp.fadeIn()
    UIView.animateWithDuration(0.7, delay: 0.7, options: .CurveEaseOut, animations: {
        self.signUp.center.x += self.view.bounds.width
        self.signUp.alpha = 0.5
        self.view.layoutIfNeeded()
        }, completion: nil)
}
}

extension UIView {
func fadeIn(duration: NSTimeInterval = 0.5, delay: NSTimeInterval = 0.0, completion: ((Bool) -> Void) = {(finished: Bool) -> Void in}) {
    UIView.animateWithDuration(duration, delay: delay, options: UIViewAnimationOptions.CurveEaseIn, animations: {
        self.alpha = 1.0
        }, completion: completion)  }

func fadeOut(duration: NSTimeInterval = 0.5, delay: NSTimeInterval = 0.0, completion: (Bool) -> Void = {(finished: Bool) -> Void in}) {
    UIView.animateWithDuration(duration, delay: delay, options: UIViewAnimationOptions.CurveEaseIn, animations: {
        self.alpha = 0.0
        }, completion: completion)
}
}

1 个答案:

答案 0 :(得分:2)

调试此视图需要有关视图开始位置的信息。但是,我强烈建议不要使用+ =或 - =这样的动画。正如您所经历的那样,它的行为是不可预测的,因为它完全取决于当前的状态。

相反,您可以在viewWillAppear中执行此操作:*view*.center.x = -(*view*.frame.width / 2) 并在viewDidAppear: view .center.x = 这里需要的任何值

此外,所有这一切的最新方法是使用和动画约束,而不是帧。