ios - 带有渐变的 UIProgressView

Question

有没有办法progressTintColor制作渐变？具体来说，我想让它成为从绿色到红色的渐变色 - 标准温度模式。

添加子图层不起作用，因为它将图层放在视图“后面”：

CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = self.testBar.bounds;
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor greenColor] CGColor], (id)[[UIColor redColor] CGColor], nil];
[self.testBar.layer insertSublayer:gradient atIndex:0];

Answer 1

您可以尝试创建带图案的 UIColor并将其设置为 tint 颜色，但我怀疑它会起作用。

否则，您可能需要继承 UIProgressView 或构建自己的 UIView 子类。进度条并不难画。

Answer 2

我发现了这个，它在我当地的效果很好

https://medium.com/academy-poa/how-to-create-a-uiprogressview-with-gradient-progress-in-swift-2d1fa7d26f24

1.Extent UIImage

    extension UIImage {
    
        public convenience init?(bounds: CGRect, colors: [UIColor], orientation: GradientOrientation = .horizontal) {
            let gradientLayer = CAGradientLayer()
            gradientLayer.frame = bounds
            gradientLayer.colors = colors.map({ $0.cgColor })
            
            if orientation == .horizontal {
                gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.5);
                gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.5);
            }
            
            UIGraphicsBeginImageContext(gradientLayer.bounds.size)
            gradientLayer.render(in: UIGraphicsGetCurrentContext()!)
            let image = UIGraphicsGetImageFromCurrentImageContext()
            UIGraphicsEndImageContext()
            
            guard let cgImage = image?.cgImage else { return nil }
            self.init(cgImage: cgImage)
        }
    }

public enum GradientOrientation {
    case vertical
    case horizontal
}

2. 创建自己的渐变进度条

导入 UIKit

class GradientProgressView: UIProgressView {
    
@IBInspectable var firstColor: UIColor = UIColor.white {
    didSet {
        updateView()
    }
}

@IBInspectable var secondColor: UIColor = UIColor.black {
    didSet {
        updateView()
    }
}

func updateView() {
            
    if let gradientImage = UIImage(bounds: self.bounds, colors: [firstColor, secondColor]) {
        self.progressImage = gradientImage
    }
}

}

3. 在你的课上

   让 progressView = GradientProgressView(progressViewStyle: .bar)

    progressView.firstColor = UIColor(red: 0.949, green: 0.478, blue: 0.329, alpha: 1) //your own color
    progressView.secondColor = UIColor(red: 0.631, green: 0.329, blue: 0.949, alpha: 1) //your own color
    progressView.updateView()