iOS 通过设置颜色去除UISearchBar的灰色背景

实现效果前：

实现效果后：

实现代码如下：

@property (weak, nonatomic) IBOutlet UISearchBar *searchbar;
通过UIImage* searchBarBg;调用下面的代码
UIImage* searchBarBg = [self GetImageWithColor:[UIColor clearColor] andHeight:32.0f];
[self.searchbar setBackgroundImage:searchBarBg];

#pragma mark 实现搜索条背景透明化
- (UIImage*) GetImageWithColor:(UIColor*)color andHeight:(CGFloat)height{
    CGRect r= CGRectMake(0.0f, 0.0f, 1.0f, height);
    UIGraphicsBeginImageContext(r.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetFillColorWithColor(context, [color CGColor]);
    CGContextFillRect(context, r);
    UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return img;
}

通过这些便实现了去除UISearchBar的灰色背景