在我的应用程序的某些时候,我有一个突出显示的UIButton(例如当用户有他的手指在按钮上),我需要改变背景颜色,而按钮是突出显示的(所以当用户的手指仍然在按钮上)。

我尝试了以下方法:

_button.backgroundColor = [UIColor redColor];

但这并不奏效。颜色保持不变。当按钮没有高亮显示时,我尝试了同一段代码,它工作得很好。我还尝试在改变颜色后调用-setNeedsDisplay,它没有任何效果。

如何强制按钮改变背景颜色?


当前回答

一个更紧凑的解决方案(基于@aleksejs-mjaliks的答案):

Swift +四分之三的:

override var isHighlighted: Bool {
    didSet {
        backgroundColor = isHighlighted ? .lightGray : .white
    }
}

斯威夫特2:

override var highlighted: Bool {
    didSet {
        backgroundColor = highlighted ? UIColor.lightGrayColor() : UIColor.whiteColor()
    }
}

如果你不想覆盖,这是一个更新版本的@timur-bernikowich的答案(Swift 4.2):

extension UIButton {
  func setBackgroundColor(_ color: UIColor, forState controlState: UIControl.State) {
    let colorImage = UIGraphicsImageRenderer(size: CGSize(width: 1, height: 1)).image { _ in
      color.setFill()
      UIBezierPath(rect: CGRect(x: 0, y: 0, width: 1, height: 1)).fill()
    }
    setBackgroundImage(colorImage, for: controlState)
  }
}

其他回答

下面是Swift中的一种方法,使用UIButton扩展来添加IBInspectable,称为highlightedBackgroundColor。类似于子类化,但不需要子类。

private var HighlightedBackgroundColorKey = 0
private var NormalBackgroundColorKey = 0

extension UIButton {

    @IBInspectable var highlightedBackgroundColor: UIColor? {
        get {
            return objc_getAssociatedObject(self, &HighlightedBackgroundColorKey) as? UIColor
        }

        set(newValue) {
            objc_setAssociatedObject(self,
                &HighlightedBackgroundColorKey, newValue, UInt(OBJC_ASSOCIATION_RETAIN))
        }
    }

    private var normalBackgroundColor: UIColor? {
        get {
            return objc_getAssociatedObject(self, &NormalBackgroundColorKey) as? UIColor
        }

        set(newValue) {
            objc_setAssociatedObject(self,
                &NormalBackgroundColorKey, newValue, UInt(OBJC_ASSOCIATION_RETAIN))
        }
    }

    override public var backgroundColor: UIColor? {
        didSet {
            if !highlighted {
                normalBackgroundColor = backgroundColor
            }
        }
    }

    override public var highlighted: Bool {
        didSet {
            if let highlightedBackgroundColor = self.highlightedBackgroundColor {
                if highlighted {
                    backgroundColor = highlightedBackgroundColor
                } else {
                    backgroundColor = normalBackgroundColor
                }
            }
        }
    }
}

我希望这能有所帮助。

一个更紧凑的解决方案(基于@aleksejs-mjaliks的答案):

Swift +四分之三的:

override var isHighlighted: Bool {
    didSet {
        backgroundColor = isHighlighted ? .lightGray : .white
    }
}

斯威夫特2:

override var highlighted: Bool {
    didSet {
        backgroundColor = highlighted ? UIColor.lightGrayColor() : UIColor.whiteColor()
    }
}

如果你不想覆盖,这是一个更新版本的@timur-bernikowich的答案(Swift 4.2):

extension UIButton {
  func setBackgroundColor(_ color: UIColor, forState controlState: UIControl.State) {
    let colorImage = UIGraphicsImageRenderer(size: CGSize(width: 1, height: 1)).image { _ in
      color.setFill()
      UIBezierPath(rect: CGRect(x: 0, y: 0, width: 1, height: 1)).fill()
    }
    setBackgroundImage(colorImage, for: controlState)
  }
}

子类化UIButton并添加可检查的属性以方便使用(在Swift 3.0中编写):

final class SelectableBackgroundButton: UIButton {

    private struct Constants {
        static let animationDuration: NSTimeInterval = 0.1
    }

    @IBInspectable
    var animatedColorChange: Bool = true

    @IBInspectable
    var selectedBgColor: UIColor = UIColor.blackColor().colorWithAlphaComponent(0.2)

    @IBInspectable
    var normalBgColor: UIColor = UIColor.clearColor()

    override var selected: Bool {
        didSet {
            if animatedColorChange {
                UIView.animateWithDuration(Constants.animationDuration) {
                    self.backgroundColor = self.selected ? self.selectedBgColor : self.normalBgColor
                }
            } else {
                self.backgroundColor = selected ? selectedBgColor : normalBgColor
            }
        }
    }

    override var highlighted: Bool {
        didSet {
            if animatedColorChange {
                UIView.animateWithDuration(Constants.animationDuration) {
                    self.backgroundColor = self.highlighted ? self.selectedBgColor : self.normalBgColor
                }
            } else {
                self.backgroundColor = highlighted ? selectedBgColor : normalBgColor
            }
        }
    }
}

在Swift 5中

对于那些不想使用彩色背景击败所选状态的人

简单地说,你可以通过使用#Selector & if语句轻松地为每个状态单独更改UIButton颜色来解决这个问题

例如:

    override func viewDidLoad() {
    super.viewDidLoad()
    self.myButtonOutlet.backgroundColor = UIColor.white  //to reset the button color to its original color ( optionally )
}

@IBOutlet weak var myButtonOutlet: UIButton!{
    didSet{  // Button selector and image here
        self.myButtonOutlet.setImage(UIImage(systemName: ""), for: UIControl.State.normal)

        self.myButtonOutlet.setImage(UIImage(systemName: "checkmark"), for: UIControl.State.selected)



        self.myButtonOutlet.addTarget(self, action: #selector(tappedButton), for: UIControl.Event.touchUpInside)
    }
}

@objc func tappedButton() {  // Colors selection is here
    if self.myButtonOutlet.isSelected == true {

        self.myButtonOutlet.isSelected = false
        self.myButtonOutlet.backgroundColor = UIColor.white         
    } else {
        self.myButtonOutlet.isSelected = true

        self.myButtonOutlet.backgroundColor = UIColor.black
        self.myButtonOutlet.tintColor00 = UIColor.white

    }
}

Swift中一个方便的通用扩展:

extension UIButton {
    private func imageWithColor(color: UIColor) -> UIImage {
        let rect = CGRectMake(0.0, 0.0, 1.0, 1.0)
        UIGraphicsBeginImageContext(rect.size)
        let context = UIGraphicsGetCurrentContext()

        CGContextSetFillColorWithColor(context, color.CGColor)
        CGContextFillRect(context, rect)

        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return image
    }

    func setBackgroundColor(color: UIColor, forUIControlState state: UIControlState) {
        self.setBackgroundImage(imageWithColor(color), forState: state)
    }
}

斯威夫特3.0

extension UIButton {
    private func imageWithColor(color: UIColor) -> UIImage? {
        let rect = CGRect(x: 0.0, y: 0.0, width: 1.0, height: 1.0)
        UIGraphicsBeginImageContext(rect.size)
        let context = UIGraphicsGetCurrentContext()

        context?.setFillColor(color.cgColor)
        context?.fill(rect)

        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return image
    }

    func setBackgroundColor(_ color: UIColor, for state: UIControlState) {
        self.setBackgroundImage(imageWithColor(color: color), for: state)
    }
}