+(UIImage *)imageWithBgColor:(UIColor *)color {
CGRect rect = CGRectMake(0.0f, 0.0f, 1, 1.0f);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [color CGColor]);
CGContextFillRect(context, rect);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
代码使用
```[self.navigationController.navigationBar setBackgroundImage:[self imageWithBgColor:[UIColor colorWithRed:243.0 / 255.0 green:82.0 / 255.0 blue:15.0 / 255.0 alpha:(self.scrollView.contentOffset.x)/150+APP.navAlpha]] forBarMetrics:UIBarMetricsDefault];```
