UITabBarItem image created in code doesn’t appear - uiview

Question

I create the following View in code, the idea is to use it as an image in UITableViewCell and UITabBarItem:
- (void)drawRect:(CGRect)rect
{
// Fill the background with white
CGContextRef context = UIGraphicsGetCurrentContext();
UIColor * whiteColor = [UIColor colorWithRed:1.0
green:1.0
blue:1.0
alpha:1.0];
CGContextSetFillColorWithColor(context, whiteColor.CGColor);
CGContextFillRect(context, self.bounds);
//// Color Declarations
UIColor* fillColor = [UIColor colorWithRed: 1.0
green: 1.0
blue: 1.0
alpha: 1.0];
UIColor* strokeColor = [UIColor colorWithRed: 0.0
green: 0.0
blue: 0.0
alpha: 1.0];
//// Big Oval Drawing
CGRect bigOvalRect = CGRectMake(rect.origin.x+2,
rect.origin.y+5,
42.0,
42.0);
UIBezierPath* bigOvalPath = [UIBezierPath bezierPath];
[bigOvalPath addArcWithCenter: CGPointMake(CGRectGetMidX(bigOvalRect), CGRectGetMidY(bigOvalRect))
radius: CGRectGetWidth(bigOvalRect) / 2
startAngle: 40 * M_PI/180
endAngle: 320 * M_PI/180
clockwise: YES];
[fillColor setFill];
[bigOvalPath fill];
[strokeColor setStroke];
bigOvalPath.lineWidth = 1;
[bigOvalPath stroke];
}
To create an UIImage from this UIView I am using this code:
#import <QuartzCore/QuartzCore.h>
+ (UIImage *) imageWithView:(UIView *)view
{
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, 0.0);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage * img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}
Everything works as expected when I use it in my UITableViewCells but when I set it as the image of my UITabBarItem I only see a blue rectangle (iOS7):
MyIcon *icon = [[MyIcon alloc] initWithFrame:CGRectMake(0.0, 0.0, 50.0, 50.0)];
UIImage *tabImage =[self imageWithView:icon];
self.navigationController.tabBarItem.image = tabImage;
I guess it is something related with the alpha of the image but how can I fix it?

Answer 1

It wasn't a problem related to the size of the view but to its alpha.
I fixed it by setting the backgroundColor (was whiteColor) and the fillColor to:
[UIColor clearColor]
and by setting the view as opaque in the initWithFrame: method:
[self setOpaque = NO];