网站上有几个类似的问题，但我正在寻找一些具体且略有不同的问题。

我按照此处给出的指示进行操作:http://www.cimgf.com/2010/01/28/fun-with-uibuttons-and-core-animation-layers/继承 UIButton 以创建一个通用类，我可以在其上指定渐变颜色，而不是尝试使用静态图像。

我遇到了一个问题，按钮层上的 setMasksToBounds 要么允许 a) 投影显示，但也允许渐变层显示超出圆角 或者 B) 渐变图层裁剪到圆角，但不允许投影显示

我对这个问题的解决方案似乎很笨拙(虽然它有效)我想看看是否有人知道更好和/或更清洁的方法来完成同样的事情。这是我的代码:

CSGradientButton.h

#import <UIKit/UIKit.h>
@interface CSGradientButton : UIButton {
    UIColor *_highColor;
    UIColor *_lowColor;
    CAGradientLayer *gradientLayer;
    CALayer *wrapperLayer;
    CGColorRef _borderColor;
}

@property (nonatomic, retain) UIColor *_highColor;
@property (nonatomic, retain) UIColor *_lowColor;
@property (nonatomic) CGColorRef _borderColor;
@property (nonatomic, retain) CALayer *wrapperLayer;
@property (nonatomic, retain) CAGradientLayer *gradientLayer;

- (void)setHighColor:(UIColor*)color;
- (void)setLowColor:(UIColor*)color;
- (void)setBorderColor:(CGColorRef)color;
- (void)setCornerRadius:(float)radius;

@end

CSGradient.m(无论如何都是有趣的部分)

#import "CSGradientButton.h" 

@implementation CSGradientButton

...

- (void)awakeFromNib
{
    // Initialize the gradient wrapper layer
    wrapperLayer = [[CALayer alloc] init];
    // Set its bounds to be the same of its parent
    [wrapperLayer setBounds:[self bounds]];
    // Center the layer inside the parent layer
    [wrapperLayer setPosition:
     CGPointMake([self bounds].size.width/2,
                 [self bounds].size.height/2)];

    // Initialize the gradient layer
    gradientLayer = [[CAGradientLayer alloc] init];
    // Set its bounds to be the same of its parent
    [gradientLayer setBounds:[self bounds]];
    // Center the layer inside the parent layer
    [gradientLayer setPosition: CGPointMake([self bounds].size.width/2,
             [self bounds].size.height/2)];

    // Insert the layer at position zero to make sure the 
    // text of the button is not obscured
    [wrapperLayer insertSublayer:gradientLayer atIndex:0];
    [[self layer] insertSublayer:wrapperLayer atIndex:0];

    // Set the layer's corner radius
    [[self layer] setCornerRadius:0.0f];
    [wrapperLayer setCornerRadius:0.0f];
    // Turn on masking
    [wrapperLayer setMasksToBounds:YES];
    // Display a border around the button 
    // with a 1.0 pixel width
    [[self layer] setBorderWidth:1.0f];

}

- (void)drawRect:(CGRect)rect
{
    if (_highColor && _lowColor)
    {
        // Set the colors for the gradient to the 
        // two colors specified for high and low
        [gradientLayer setColors:
         [NSArray arrayWithObjects:
          (id)[_highColor CGColor], 
          (id)[_lowColor CGColor], nil]];
    }

    [super drawRect:rect];
}

- (void)setCornerRadius:(float)radius
{
    [[self layer] setCornerRadius:radius];
    // and get the wrapper for the gradient layer too
    [wrapperLayer setCornerRadius:radius];
}

- (void)setHighColor:(UIColor*)color
{
    // Set the high color and repaint
    [self set_highColor:color];
    [[self layer] setNeedsDisplay];
}

- (void)setLowColor:(UIColor*)color
{
    // Set the low color and repaint
    [self set_lowColor:color];
    [[self layer] setNeedsDisplay];
}

- (void)setBorderColor:(CGColorRef)color
{
    [[self layer] setBorderColor:color];
    [[self layer] setNeedsDisplay];
}


@end

如您所见，我添加了一个“包装”层，渐变层可以安全地遮盖到该层，而按钮 View 的顶层 CALayer 可以在添加阴影时安全地设置 masksToBounds = NO。我添加了一个 setCornerRadius: 方法来允许顶层和“包装器”进行调整。

因此，与其做类似[[myCustomButton layer] setCornerRadius:3.0f]; 的事情，不如说[myCustomButton setCornerRadius:3.0f]; 如你所见，它可能不像我希望的那样干净。

有没有更好的办法？

最佳答案

这是我发现具有圆角、渐变和投影的按钮的方式。这个例子有一个特定的渐变，但显然可以用其他渐变替换。

@implementation CustomButton

- (id)initWithFrame:(CGRect)frame
{
    if((self = [super initWithFrame:frame])){
        [self setupView];
    }

    return self;
}

- (void)awakeFromNib {
    [self setupView];
}

# pragma mark - main

- (void)setupView
{
    self.layer.cornerRadius = 10;
    self.layer.borderWidth = 1.0;
    self.layer.borderColor = [UIColor colorWithRed:167.0/255.0 green:140.0/255.0 blue:98.0/255.0 alpha:0.25].CGColor;
    self.layer.shadowColor = [UIColor blackColor].CGColor;
    self.layer.shadowRadius = 1;
    [self clearHighlightView];

    CAGradientLayer *gradient = [CAGradientLayer layer];
    gradient.frame = self.layer.bounds;
    gradient.cornerRadius = 10;
    gradient.colors = [NSArray arrayWithObjects:
                         (id)[UIColor colorWithWhite:1.0f alpha:1.0f].CGColor,
                         (id)[UIColor colorWithWhite:1.0f alpha:0.0f].CGColor,
                         (id)[UIColor colorWithWhite:0.0f alpha:0.0f].CGColor,
                         (id)[UIColor colorWithWhite:0.0f alpha:0.4f].CGColor,
                         nil];
    float height = gradient.frame.size.height;
    gradient.locations = [NSArray arrayWithObjects:
                            [NSNumber numberWithFloat:0.0f],
                            [NSNumber numberWithFloat:0.2*30/height],
                            [NSNumber numberWithFloat:1.0-0.1*30/height],
                            [NSNumber numberWithFloat:1.0f],
                            nil];
    [self.layer addSublayer:gradient];}

- (void)highlightView 
{
    self.layer.shadowOffset = CGSizeMake(1.0f, 1.0f);
    self.layer.shadowOpacity = 0.25;
}

- (void)clearHighlightView {
    self.layer.shadowOffset = CGSizeMake(2.0f, 2.0f);
    self.layer.shadowOpacity = 0.5;
}

- (void)setHighlighted:(BOOL)highlighted
{
    if (highlighted) {
        [self highlightView];
    } else {
        [self clearHighlightView];
    }
    [super setHighlighted:highlighted];
}


@end

关于ios - 带有渐变、圆角、边框和阴影的 UIButton，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/5971073/