iOS开发渐变色与十六进制颜色转UIColor的封装

.h中

@interface UIColor (Transform)

//十六进制颜色转UIColor

+ (UIColor *)colorWithHexString:(NSString*)stringToConvert;

/** 渐变色 */
+ (CAGradientLayer *)setGradualChangingColor:(UIView *)view fromColor:(NSString *)fromHexColorStr toColor:(NSString *)toHexColorStr;

@end

.m中

+ (UIColor *)colorWithHexString:(NSString*)stringToConvert{
    if([stringToConvert hasPrefix:@"#"])
    {
        stringToConvert = [stringToConvert substringFromIndex:1];
    }
    NSScanner*scanner = [NSScanner scannerWithString:stringToConvert];
    unsigned hexNum;
    if(![scanner scanHexInt:&hexNum])
    {
        return nil;
    }
    
    return [self colorWithRGBHex:hexNum];
}

+ (UIColor *)colorWithRGBHex:(UInt32)hex{
    int r = (hex >>16) &0xFF;
    int g = (hex >>8) &0xFF;
    int b = (hex) &0xFF;
    return[UIColor colorWithRed:r /255.0f
                          green:g /255.0f
                           blue:b /255.0f
                          alpha:1.0f];
}

/** 渐变色 */
+ (CAGradientLayer *)setGradualChangingColor:(UIView *)view fromColor:(NSString *)fromHexColorStr toColor:(NSString *)toHexColorStr{
    //    CAGradientLayer类对其绘制渐变背景颜色、填充层的形状(包括圆角)
    CAGradientLayer *gradientLayer = [CAGradientLayer layer];
    gradientLayer.frame = view.bounds;
    //  创建渐变色数组，需要转换为CGColor颜色
    gradientLayer.colors = @[(__bridge id)[UIColor colorWithHexString:fromHexColorStr].CGColor,(__bridge id)[UIColor colorWithHexString:toHexColorStr].CGColor];
    //  设置渐变颜色方向，左上点为(0,0), 右下点为(1,1)
    gradientLayer.startPoint = CGPointMake(0, 0);
    gradientLayer.endPoint = CGPointMake(0, 1);
    //  设置颜色变化点，取值范围 0.0~1.0
    gradientLayer.locations = @[@0,@1];
    
    return gradientLayer;
}