网上搜了有关于iOS根据scrollview滑动值实现导航栏颜色渐变效果但没有搜出相关结果，所以参照了安卓的实现，希望本篇对大家的开发有所帮助。
详细代码：iOS 根据Banner滑动 改变顶部视图颜色 - 简书
代码：
```Objective-C
+ (NSArray*)getRGBWithColor:(NSString*)color {
// 从六位数值中找到RGB对应的位数并转换
NSRange range;
range.location=0;
range.length=2;
//R、G、B
NSString*rString = [colorsubstringWithRange:range];
range.location=2;
NSString*gString = [colorsubstringWithRange:range];
range.location=4;
NSString*bString = [colorsubstringWithRange:range];
// Scan values
unsignedintr, g, b;
[[NSScanner scannerWithString:rString] scanHexInt:&r];
[[NSScanner scannerWithString:gString] scanHexInt:&g];
[[NSScanner scannerWithString:bString] scanHexInt:&b];
return@[@(r),@(g),@(b)];
}
+ (NSArray*)getRGBWithFromColor:(NSString*)fromColor toColor:(NSString*)toColor shade:(CGFloat)mShade {
NSArray*fromeRgb = [SPUtils getRGBWithColor:fromColor];
NSArray*toRgb = [SPUtils getRGBWithColor:toColor];
intfromR = [fromeRgb[0]intValue];
intfromG = [fromeRgb[1]intValue];
intfromB = [fromeRgb[2]intValue];
inttoR = [toRgb[0]intValue];
inttoG = [toRgb[1]intValue];
inttoB = [toRgb[2]intValue];
intdiffR = toR - fromR;
intdiffG = toG - fromG;
intdiffB = toB - fromB;
intred = fromR + (int) ((diffR * mShade));
intgreen = fromG + (int) ((diffG * mShade));
intblue = fromB + (int) ((diffB * mShade));
return@[@(red /255.0f),@(green /255.0f),@(blue /255.0f)];
}
```
mShade是你的scrollview的滑动值，+ (NSArray*)getRGBWithFromColor:(NSString*)fromColor toColor:(NSString*)toColor shade:(CGFloat)mShade; 方法得到的是NSNumber类型，需要转成CGFloat类型
CGFloat red = [rgb[0] floatValue];
CGFloat green = [rgb[1] floatValue];
CGFloat blue = [rgb[2] floatValue];
UIColor *bgColor = [UIColor colorWithRed:red green:green blue:blue alpha:1.0f];
