snapshotViewAfterScreenUpdates on UIScreen gives blank snapshot on device

Question

I'm trying to get an image of the entire screen as the user sees it. The following code should work however it will only work in the simulator. What do I have to do to get this to work on a device running iOS 8.1?

UIView *snapshot = [[UIScreen mainScreen] snapshotViewAfterScreenUpdates:YES];
CGSize outputSize = CGSizeMake([UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height);
UIGraphicsBeginImageContextWithOptions(outputSize, NO, 0);
[snapshot drawViewHierarchyInRect:CGRectMake(0.0, 0.0, outputSize.width, outputSize.height) afterScreenUpdates:YES];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

Happy to try alternative strategies but the key is I want it as the user sees it - keyboards and all.

Cheers

Answer 1

UIGraphicsBeginImageContextWithOptions(CGSizeMake(CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame)), NO, 1.0f);
        [self.view drawViewHierarchyInRect:CGRectMake(0, 0, CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame)) afterScreenUpdates:NO];
        UIImage *snapshotImage = UIGraphicsGetImageFromCurrentImageContext();