iOS开发点滴－添加阴影效果

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;