swift - View 没有动画

Question

我有一个 View ，它应该像抽屉一样从屏幕底部向上移动。但它什么都不做。它只是坐在那里 =)谁能告诉我，为什么要这样做？

这是我的代码:

import UIKit

class InfoPopUpVC: UIViewController {
  var superView: UIView!
  var labelText: String!
  let textLabel =  UILabel()
  let height = CGFloat(80)


  override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)
    UIView.animateWithDuration(0.4, animations: { () -> Void in
      self.view.center.y = 50
    })
  }

override func viewDidLoad() {
  super.viewDidLoad()
  setupTextLabel()
  view.frame = CGRectMake(0, superView.frame.maxY-height, superView.frame.width, height)
  AnimationHelper.blurBackgroundForView(view)
  view.backgroundColor = .greenColor()
  }

func setupTextLabel(){
  textLabel.text = labelText
  textLabel.frame = CGRectMake(0, 0, view.frame.width, view.frame.height)
  textLabel.numberOfLines = 3
  textLabel.textAlignment = .Center

  textLabel.frame.inset(dx: 10, dy: 8)
  textLabel.sizeToFit()
  textLabel.font = UIFont(name: "HelveticaNeue-Light", size: 17)
  textLabel.textColor = .whiteColor()
  view.addSubview(textLabel)
  }
}

Answer 1

尝试将您的代码如下放入 viewDidAppear 或 viewWillAppear 中，并使用异步调度。否则你的动画可能无法工作。

 override func viewDidAppear(animated: Bool) {
dispatch_async(dispatch_get_main_queue(), {
            UIView.animateWithDuration(0.4, animations: { () -> Void in
      self.view.center.y = 50
    })
        })
}