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

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)
    }
}

其他回答

如果你有一张图片,试试这个:

-(void)setBackgroundImage:(UIImage *)image forState:(UIControlState)state;

或者看看showsTouchWhenHighlighted是否足够。

你可以通过简单地使用UIButton上的setBackgroundImage方法,并使用这个UIImage(color:)初始化项来使用一张图像,像这样轻松地更改高亮显示/选中的按钮背景颜色:

btn.setBackgroundImage(UIImage(color: .black), for: .highlighted)

注意:

如果你为圆角边框使用cornerRadius属性,你必须将clipsToBounds设置为true,这样所选的背景颜色将保留圆角半径值。

UIButton扩展与Swift 3+语法:

extension UIButton {
    func setBackgroundColor(color: UIColor, forState: UIControlState) {
        UIGraphicsBeginImageContext(CGSize(width: 1, height: 1))
        UIGraphicsGetCurrentContext()!.setFillColor(color.cgColor)
        UIGraphicsGetCurrentContext()!.fill(CGRect(x: 0, y: 0, width: 1, height: 1))
        let colorImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        self.setBackgroundImage(colorImage, for: forState)
    }}

像这样使用它:

YourButton.setBackgroundColor(color: UIColor.white, forState: .highlighted)

最初的回答: https://stackoverflow.com/a/30604658/3659227

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)
    }
}

解决方案Swift 3+没有子类化。

extension UIButton {
  func setBackgroundColor(_ color: UIColor, for state: UIControlState) {
    let rect = CGRect(x: 0, y: 0, width: 1, height: 1)
    UIGraphicsBeginImageContext(rect.size)
    color.setFill()
    UIRectFill(rect)
    let colorImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    setBackgroundImage(colorImage, for: state)
  }
}

有了这个扩展,它很容易管理不同状态的颜色,它会自动褪色你的正常颜色,如果高亮的颜色是不提供的。

button.setBackgroundColor(.red, for: .normal)