Ios7 透明UIToolBar与非透明UIBarButtonim

我有一个透明的UIToolbar，通过设置半透明为true并更改背景alpha。如何使工具栏按钮不透明？我尝试添加如下非透明图像：

CGRect rect = CGRectMake(0, 0, ([AppDelegate isInIPad])?768:320, 20);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [[UIColor redColor] CGColor]);
CGContextFillRect(context, rect);

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

[self.filterButton setBackgroundImage:image forToolbarPosition:UIBarPositionAny barMetrics:UIBarMetricsDefault];

试试这个：

[yourToolbar setBackgroundImage:[UIImage new] forToolbarPosition:UIToolbarPositionAny barMetrics:UIBarMetricsDefault];    
[yourToolbar setBackgroundColor:[UIColor clearColor]];    
[yourToolbar setShadowImage:[UIImage new] forToolbarPosition:UIToolbarPositionAny];