UIButton - 默认图像高亮颜色是什么

Question

是否有任何方法如何从某种颜色（比如它的[UIColor redColor]）创建这种颜色的默认突出显示颜色（在这种情况下是某种深红色）。

在我的情况下，我有一个UIButton（在UIBarButton内部），我想为UIControlStateHighlighted状态设置titleColor，与UIImage的默认高亮颜色相同。请参阅以下代码：

UIColor *color = [UIColor redColor];
UIColor *highlightedColor = ???;

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];

[button setImage:[[UIImage imageNamed:@"back-arrow"] imageWithOverlayColor:color] forState:UIControlStateNormal];
[button setImage:[[UIImage imageNamed:@"back-arrow"] imageWithOverlayColor:highlightedColor] forState:UIControlStateHighlighted];

[button setTitle:title forState:UIControlStateNormal];
[button setTitleColor:color forState:UIControlStateNormal];
[button setTitleColor:highlightedColor forState:UIControlStateHighlighted];

button.imageEdgeInsets = UIEdgeInsetsMake(0.f, -5.f, 0.f, 0.f);

如果我没有为UIControlStateHighlighted状态设置图像/标题，则只有按下按钮时图像会突出显示：

Answer 1

你需要将两种UIColor合并在一起， 首先，你可以使用tintColor：

UIColor *defualtTintColor = self.navigationController.navigationItem.backBarButtonItem.tintColor;

将redColor和defualtTintColor合并在一起。 这是我的方法，非常优雅，但它确实有效：

UIColor* blend( UIColor* c1, UIColor* c2, float alpha )
{
    alpha = MIN( 1.f, MAX( 0.f, alpha ) );
    float beta = 1.f - alpha;
    CGFloat r1, g1, b1, a1, r2, g2, b2, a2;
    [c1 getRed:&r1 green:&g1 blue:&b1 alpha:&a1];
    [c2 getRed:&r2 green:&g2 blue:&b2 alpha:&a2];
    CGFloat r = r1 * beta + r2 * alpha;
    CGFloat g = g1 * beta + g2 * alpha;
    CGFloat b = b1 * beta + b2 * alpha;
    return [UIColor colorWithRed:r green:g blue:b alpha:1.f];
}

更优雅：

的UIColor + Extensions.h：

@interface UIColor (Extensions)

- (UIColor*)blendWithColor:(UIColor*)color2 alpha:(CGFloat)alpha2;

@end

的UIColor + Extensions.m：

@implementation UIColor (Extensions)

- (UIColor*)blendWithColor:(UIColor*)color2 alpha:(CGFloat)alpha2
{
    alpha2 = MIN( 1.0, MAX( 0.0, alpha2 ) );
    CGFloat beta = 1.0 - alpha2;
    CGFloat r1, g1, b1, a1, r2, g2, b2, a2;
    [self getRed:&r1 green:&g1 blue:&b1 alpha:&a1];
    [color2 getRed:&r2 green:&g2 blue:&b2 alpha:&a2];
    CGFloat red     = r1 * beta + r2 * alpha2;
    CGFloat green   = g1 * beta + g2 * alpha2;
    CGFloat blue    = b1 * beta + b2 * alpha2;
    CGFloat alpha   = a1 * beta + a2 * alpha2;
    return [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
}

@end

然后你可以获得highlightColor：

UIColor *color = [UIColor redColor];
UIColor *defualtTintColor = self.navigationController.navigationItem.backBarButtonItem.tintColor;
UIColor *highlightedColor = [defualtTintColor blendWithColor:color alpha:0.75];

Answer 2

只需为按钮添加highlightImage

即可

@implementation UIButton (YASAddition)

- (void)awakeFromNib {
    [super awakeFromNib];

    UIImage *highlightedImage = [UIImage imageWithColor:[[UIColor colorWithHex:0X1E1E1E] colorWithAlphaComponent:0.2f]];
    [self setBackgroundImage:highlightedImage forState:UIControlStateHighlighted];
}

@end

UIBarButtonItem

相同

alpha是重点