UIButton不尊重Aspect在调整animation大小后填充contentMode

我使用自动布局。 以下是视图的初始状态。

在中心是一个包含在视图中的button。 该button具有contentMode Aspect Fill，并且图像被设置为button的背景图像。

然后，我使用下面的代码来转换视图，这将放大中心卡填充屏幕，并将图像移动到视图顶部：

cardTrailingSpaceConstraint.constant = 0 cardLeadingSpaceConstraint.constant = 0 cardView.removeConstraint(cardAspectRatioConstraint) let cardHeightConstraint = NSLayoutConstraint(item: cardView, attribute: .Height, relatedBy: .Equal, toItem: view, attribute: .Height, multiplier: 1.0, constant: 0) view.addConstraint(cardHeightConstraint) dishImageButton.removeConstraint(dishButtonBottomSpaceConstraint) let dishButtonHeightConstraint = NSLayoutConstraint(item: dishImageButton, attribute: .Height, relatedBy: .Equal, toItem: cardView, attribute: .Height, multiplier: 0.2, constant: 0) cardView.addConstraint(dishButtonHeightConstraint) cardView.setNeedsUpdateConstraints() UIView.animateWithDuration(0.7, delay: 0, usingSpringWithDamping: 0.7, initialSpringVelocity: 0.7, options: nil, animations: { [unowned self] () -> Void in self.cardHeader.alpha = 0 self.cardView.layer.cornerRadius = 0 self.cardView.layoutIfNeeded() }) { [unowned self] (finished) -> Void in } 

结果是：

但是，这不是我想要的。 该button不尊重contentMode，然后图像被拉伸。

任何人都可以告诉我如何保持button的方面填充contentMode？

Answer 1

1. 将buttontypes设置为UIButtonTypeCustom （在故事板或xib中的“自定义”）。
2. 设置button的图像，而不是button的背景图像。
3. 在viewDidLoad ，将button.imageView.contentMode设置为UIViewContentMode.ScaleAspectFill 。

Answer 2

Swift 3

---

从Rob的回答中走出来：

  let btn = UIButton(frame: CGRect(x: 0, y: 0, width: 80, height: 30)) btn.setImage(UIImage(named: "albumsBtn"), for: UIControlState.normal) btn.imageView?.contentMode = UIViewContentMode.scaleAspectFit btn.addTarget(self.navigationController, action: #selector(CustomGalleryViewController.showAlbums(_:)), for: UIControlEvents.touchUpInside) let item = UIBarButtonItem(customView: btn) self.navigationItem.leftBarButtonItem = item 

Answer 3

Swift 2.x版本：

 let myButton = UIButton(type: .Custom) myButton.frame = CGRectMake(0, 0, 200, 20) myButton.backgroundColor = UIColor.blackColor() myButton.imageView.contentMode = .ScaleAspectFill // ALTERNATIVE: .ScaleAspectFit myButton.setImage(UIImage(named: "myImageName"), forState: .Normal) myButton.addTarget(self, action: #selector(buttonAction), forControlEvents: .TouchUpInside) view.addSubview(myButton) 

Answer 4

Swift 2

 button.imageView?.contentMode = UIViewContentMode.ScaleAspectFit 

所有contentMode：

  .ScaleToFill .ScaleAspectFit .ScaleAspectFill .Redraw .Center .Top .Bottom .Left .Right .TopLeft .TopRight .BottomLeft .BottomRight 

Answer 5

斯威夫特4

延期

 // Inspectable image content mode extension UIButton { /// 0 => .ScaleToFill /// 1 => .ScaleAspectFit /// 2 => .ScaleAspectFill @IBInspectable var imageContentMode: Int { get { return self.imageView?.contentMode.rawValue ?? 0 } set { if let mode = UIViewContentMode(rawValue: imageContentMode), self.imageView != nil { self.imageView?.contentMode = mode } } } }