Ios 调整动画大小后，UIButton不尊重Aspect Fill contentMode

我正在使用自动布局。以下是视图的初始状态

中间是一个包含在视图中的按钮。按钮具有contentMode Aspect Fill，并且图像被设置为按钮的背景图像

然后，我使用以下代码转换视图，这将放大中心卡以填充屏幕，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：

然而，这不是我想要的。该按钮不符合contentMode，因此图像会被拉伸

有人能告诉我如何维护按钮的Aspect Fill contentMode吗

将按钮类型设置为

uibuttonypecustom

（“脚本或xib中的自定义”）

设置按钮的图像，而不是按钮的背景图像

在

viewDidLoad

中，将

按钮.imageView.contentMode

设置为

UIViewContentMode.ScaleAspectFill

---

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)

斯威夫特2

button.imageView?.contentMode = UIViewContentMode.ScaleAspectFit

所有内容模式：

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

---

Swift 3

---

从Rob的回答开始：

    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

Swift 4.2 扩展

更新：这个和其他答案在ios 11中对我不起作用。最接近的答案是@Jaro，但我认为最好制作一个UIImageView并在其上添加一个按钮，或者创建一个自定义的UIImageView类，该类将有一个手势识别器并单击动画。

可能对某人有所帮助

button.subviews.first?.contentMode = .scaleAspectFit

---

请在[btn setImage:forState:][/strong>用法之前尝试此操作：

    btn.contentHorizontalAlignment = UIControlContentHorizontalAlignmentFill;
    btn.contentVerticalAlignment = UIControlContentVerticalAlignmentFill;

• 斯威夫特4

---

您可以对按钮进行子类化并添加以下内容：

class FitButton: UIButton {

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)


    }

    override func layoutSubviews() {
        self.imageView?.contentMode = .scaleAspectFill
        self.contentHorizontalAlignment = .fill
        self.contentVerticalAlignment = .fill
        super.layoutSubviews()


    }

}

---

在Xcode 10.1中，您可以使用interface builder。在右侧的属性检查器中，按如下方式使用控制部分：

---

这种语言似乎有了更新

为了获得xscoder解决方案，我必须深入挖掘：

myButton.imageView.contentMode = .ScaleAspectFill 

更新版本如下：

myButton.imageView？.contentMode=UIView.contentMode.scalespectfit

Swift

for按钮具有contentMode方面填充：

btn.contentHorizontalAlignment = .fill
btn.contentVerticalAlignment = .fill
btn.imageView?.contentMode = .scaleAspectFill

---

当我使用BarButtonItem的自定义按钮时，这个解决方案对我有效

1.正在从服务器加载图像
2.裁剪图像
3.设置按钮的图像

以下是裁剪图像的功能：

extension UIImage {
  func crop(to:CGSize) -> UIImage {
    guard let cgimage = self.cgImage else { return self }

    let contextImage: UIImage = UIImage(cgImage: cgimage)

    let contextSize: CGSize = contextImage.size

    //Set to square
    var posX: CGFloat = 0.0
    var posY: CGFloat = 0.0
    let cropAspect: CGFloat = to.width / to.height

    var cropWidth: CGFloat = to.width
    var cropHeight: CGFloat = to.height

    if to.width > to.height { //Landscape
        cropWidth = contextSize.width
        cropHeight = contextSize.width / cropAspect
        posY = (contextSize.height - cropHeight) / 2
    } else if to.width < to.height { //Portrait
        cropHeight = contextSize.height
        cropWidth = contextSize.height * cropAspect
        posX = (contextSize.width - cropWidth) / 2
    } else { //Square
        if contextSize.width >= contextSize.height { //Square on landscape (or square)
            cropHeight = contextSize.height
            cropWidth = contextSize.height * cropAspect
            posX = (contextSize.width - cropWidth) / 2
        }else{ //Square on portrait
            cropWidth = contextSize.width
            cropHeight = contextSize.width / cropAspect
            posY = (contextSize.height - cropHeight) / 2
        }
    }

    let rect: CGRect = CGRect(x : posX, y : posY, width : cropWidth, height : cropHeight)

    // Create bitmap image from context using the rect
    let imageRef: CGImage = contextImage.cgImage!.cropping(to: rect)!

    // Create a new image based on the imageRef and rotate back to the original orientation
    let cropped: UIImage = UIImage(cgImage: imageRef, scale: self.scale, orientation: self.imageOrientation)

    cropped.draw(in: CGRect(x : 0, y : 0, width : to.width, height : to.height))

    return cropped
  }
}

扩展UIImage{ func裁剪（到：CGSize）->UIImage{ guard let cgimage=self.cgimage else{return self} 让contextImage:UIImage=UIImage（cgImage:cgImage） 让contextSize:CGSize=contextImage.size //摆正 var posX:CGFloat=0.0 变量posY:CGFloat=0.0 让CropSpect:CGFloat=to.width/to.height 变量cropWidth:CGFloat=to.width 变量cropHeight:CGFloat=to.height 如果to.width>to.height{// cropWidth=contextSize.width cropHeight=contextSize.width/cropspect posY=（contextSize.height-cropHeight）/2 }否则，如果to.width=contextSize.height{//横向正方形（或正方形） cropHeight=contextSize.height cropWidth=contextSize.height*CropSpect posX=（contextSize.width-cropWidth）/2 }else{//肖像上的正方形 cropWidth=contextSize.width cropHeight=contextSize.width/cropspect posY=（contextSize.height-cropHeight）/2 } } 设rect:CGRect=CGRect（x:posX，y:posY，宽度：cropWidth，高度：cropHeight） //使用rect从上下文创建位图图像 让imageRef:CGImage=contextImage.CGImage！。裁剪（到：rect）！ //基于imageRef创建新图像并旋转回原始方向 让裁剪：UIImage=UIImage（cgImage:imageRef，比例：self.scale，方向：self.imageOrientation） 裁剪的.draw（in:CGRect（x:0，y:0，宽度：到.width，高度：到.height）） 复种 } }

---

Swift 5.0

带有

的自定义
ui按钮的代码

var mainImageButton : UIButton = {
    var imageButton = UIButton()
    imageButton.translatesAutoresizingMaskIntoConstraints = false
    imageButton.contentMode = .scaleAspectFit
    imageButton.backgroundColor = .white
    imageButton.layer.cornerRadius = 80 / 2

    // The short way
    imageButton.contentMode = .scaleAspectFit

    // The long way
    imageButton.imageView?.contentMode = UIView.ContentMode.scaleAspectFill

    imageButton.clipsToBounds = true
    return imageButton
}()

为我工作。请记住，在#3上，将其绑定到IBOutlet以获得正确的按钮。这非常有效，但现在我遇到了约束问题。如何将目标约束到图像按钮，而不是背景按钮图像？在Swift 5.2上工作。我的问题是我设置的是背景图像而不是图像。谢谢肯定对我来说，直到我自定义了类型，它才起作用。谢谢。您应该在扩展行中添加@IBDesignable，这样它才能在接口生成器Wift 4.2扩展UIButton{///0=>。ScaleToFill///1=>。scaleSpectFit///2=>。scaleSpectFill@IBInspectable var imageContentMode:Int{get{return self.imageView？.contentMode.rawValue？？0}设置{if let mode=UIView.ContentMode（rawValue:newValue），self.imageView！=nil{self.imageView？.ContentMode=mode}}
extension UIImage {
  func crop(to:CGSize) -> UIImage {
    guard let cgimage = self.cgImage else { return self }

    let contextImage: UIImage = UIImage(cgImage: cgimage)

    let contextSize: CGSize = contextImage.size

    //Set to square
    var posX: CGFloat = 0.0
    var posY: CGFloat = 0.0
    let cropAspect: CGFloat = to.width / to.height

    var cropWidth: CGFloat = to.width
    var cropHeight: CGFloat = to.height

    if to.width > to.height { //Landscape
        cropWidth = contextSize.width
        cropHeight = contextSize.width / cropAspect
        posY = (contextSize.height - cropHeight) / 2
    } else if to.width < to.height { //Portrait
        cropHeight = contextSize.height
        cropWidth = contextSize.height * cropAspect
        posX = (contextSize.width - cropWidth) / 2
    } else { //Square
        if contextSize.width >= contextSize.height { //Square on landscape (or square)
            cropHeight = contextSize.height
            cropWidth = contextSize.height * cropAspect
            posX = (contextSize.width - cropWidth) / 2
        }else{ //Square on portrait
            cropWidth = contextSize.width
            cropHeight = contextSize.width / cropAspect
            posY = (contextSize.height - cropHeight) / 2
        }
    }

    let rect: CGRect = CGRect(x : posX, y : posY, width : cropWidth, height : cropHeight)

    // Create bitmap image from context using the rect
    let imageRef: CGImage = contextImage.cgImage!.cropping(to: rect)!

    // Create a new image based on the imageRef and rotate back to the original orientation
    let cropped: UIImage = UIImage(cgImage: imageRef, scale: self.scale, orientation: self.imageOrientation)

    cropped.draw(in: CGRect(x : 0, y : 0, width : to.width, height : to.height))

    return cropped
  }
}

var mainImageButton : UIButton = {
    var imageButton = UIButton()
    imageButton.translatesAutoresizingMaskIntoConstraints = false
    imageButton.contentMode = .scaleAspectFit
    imageButton.backgroundColor = .white
    imageButton.layer.cornerRadius = 80 / 2

    // The short way
    imageButton.contentMode = .scaleAspectFit

    // The long way
    imageButton.imageView?.contentMode = UIView.ContentMode.scaleAspectFill

    imageButton.clipsToBounds = true
    return imageButton
}()