CALayer *subLayer = [CALayer layer];

CGRect fixframe = view1.frame;

subLayer.frame = fixframe;

subLayer.cornerRadius = 8;

subLayer.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.8].CGColor;

subLayer.masksToBounds = NO;

subLayer.shadowColor =? [UIColor blackColor].CGColor;//shadowColor陰影顏色

subLayer.shadowOffset = CGSizeMake(3,2);//shadowOffset陰影偏移,x向右偏移3，y向下偏移2，默認(0, -3),這個跟shadowRadius配合使用

subLayer.shadowOpacity = 0.8;//陰影透明度，默認0

subLayer.shadowRadius = 4;//陰影半徑，默認3

[self.view.layerinsertSublayer:subLayerbelow:view1.layer];