Question

我正在通过向按钮添加线性渐变来创建看上去很漂亮的UI按钮。但是我不确定我需要添加渐变的索引。我目前的代码将渐变放在图像/文本上。

如何将子图层插入文本/图像子图层下的UIButton？对我来说，保持文本和按钮图像可见非常重要！

+(void)addLinearGradientToView:(UIView*)view TopColor:(UIColor*)topColor BottomColor:(UIColor*)bottomColor
{
    for(CALayer* layer in view.layer.sublayers)
    {
        if ([layer isKindOfClass:[CAGradientLayer class]])
        {
            [layer removeFromSuperlayer];
        }
    }
    CAGradientLayer* gradientLayer = [CAGradientLayer layer];

    gradientLayer.startPoint = CGPointMake(0.5, 0);
    gradientLayer.endPoint = CGPointMake(0.5,1);
    gradientLayer.frame = view.bounds;
    gradientLayer.colors = [NSArray arrayWithObjects:(id)[topColor CGColor], (id)[bottomColor CGColor], nil];
    //    [view.layer addSublayer:gradientLayer];
    if(view.layer.sublayers.count>0)
    {
        [view.layer insertSublayer:gradientLayer atIndex:view.layer.sublayers.count-2];
    }else {
        [view.layer addSublayer:gradientLayer];
    }
}

Answer 1

将其添加到自定义按钮的图层：

CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.frame = customButton.layer.bounds;

gradientLayer.colors = [NSArray arrayWithObjects:
                        (id)[UIColor colorWithWhite:1.0f alpha:0.1f].CGColor,
                        (id)[UIColor colorWithWhite:0.4f alpha:0.5f].CGColor,
                        nil];

gradientLayer.locations = [NSArray arrayWithObjects:
                           [NSNumber numberWithFloat:0.0f],
                           [NSNumber numberWithFloat:1.0f],
                           nil];

gradientLayer.cornerRadius = customButton.layer.cornerRadius;
[customButton.layer addSublayer:gradientLayer];

其中customButton是您的自定义UIButton。

Answer 2

对于您要实现的目标，请始终在索引0处插入。

我最近写了关于这类事情的an article，你可能会感兴趣。

Answer 3

以下是实现此目的的代码

CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = <#View Variable Name#>.bounds;
gradient.colors = [NSArray arrayWithObjects:(id)([UIColor colorWithRed:0.337 green:0.596 blue:1.000 alpha:1.000].CGColor),(id)([UIColor colorWithRed:0.757 green:0.459 blue:1.000 alpha:1.000].CGColor),(id)([UIColor colorWithRed:0.310 green:0.835 blue:1.000 alpha:1.000].CGColor),nil];
gradient.startPoint = CGPointMake(0.5,0.0);
gradient.endPoint = CGPointMake(0.5,1.0);
[<#View Variable name#>.layer insertSublayer:gradient atIndex:0];

我使用此工具可以轻松选择颜色并自动输出渐变代码。非常方便我每天都使用它 itunes.apple.com/gb/app/gradient-creator/id1031070259?mt=12

Answer 4

快捷键4

@IBOutlet weak var gButton: UIButton!

override func viewDidLoad() {

    super.viewDidLoad()

    let topGradientColor = UIColor.red
    let bottomGradientColor = UIColor.yellow

    let gradientLayer = CAGradientLayer()

    gradientLayer.frame = gButton.bounds

    gradientLayer.colors = [topGradientColor.cgColor, bottomGradientColor.cgColor]

    //Vertical
    //gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.0)
    //gradientLayer.endPoint = CGPoint(x: 0.0, y: 1.0)

    //Horizontal
    gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.0)
    gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.0)

    gButton.layer.insertSublayer(gradientLayer, at: 0)
}

iPhone iOS如何在按钮的文本或图像下添加线性渐变到UIButton？

4 个答案: