UIBezierPath *shadowPath = [UIBezierPath
bezierPathWithRect:_backView.bounds];
_backView.layer.masksToBounds =
NO;
_backView.layer.shadowColor = [UIColor
blackColor].CGColor;
_backView.layer.shadowOffset =
CGSizeMake(3.0f,
3.0f);
_backView.layer.shadowOpacity =
0.5f;
_backView.layer.shadowRadius=10;
_backView.layer.shadowPath = shadowPath.CGPath;