iPhone之为UIView设置阴影(CALayer的shadowColor，shadowOffset，shadowOpacity，shadowRadius,shadowPath属性)

效果图：

以下代码实现：

第一个图片的代码

//加阴影--任海丽编辑    _imageView.layer.shadowColor = [UIColor blackColor].CGColor;//shadowColor阴影颜色    _imageView.layer.shadowOffset = CGSizeMake(4,4);//shadowOffset阴影偏移,x向右偏移4，y向下偏移4，默认(0, -3),这个跟shadowRadius配合使用    _imageView.layer.shadowOpacity = 0.8;//阴影透明度，默认0    _imageView.layer.shadowRadius = 4;//阴影半径，默认3

第二个图片的代码

    _imageView1.layer.shadowColor = [UIColor yellowColor].CGColor;//shadowColor阴影颜色    _imageView1.layer.shadowOffset = CGSizeMake(0,0);//shadowOffset阴影偏移，默认(0, -3),这个跟shadowRadius配合使用    _imageView1.layer.shadowOpacity = 1;//阴影透明度，默认0    _imageView1.layer.shadowRadius = 3;//阴影半径，默认3        //路径阴影    UIBezierPath *path = [UIBezierPath bezierPath];    float width = _imageView1.bounds.size.width;    float height = _imageView1.bounds.size.height;    float x = _imageView1.bounds.origin.x;    float y = _imageView1.bounds.origin.y;    float addWH = 10;        CGPoint topLeft      = _imageView1.bounds.origin;    CGPoint topMiddle = CGPointMake(x+(width/2),y-addWH);    CGPoint topRight     = CGPointMake(x+width,y);        CGPoint rightMiddle = CGPointMake(x+width+addWH,y+(height/2));        CGPoint bottomRight  = CGPointMake(x+width,y+height);    CGPoint bottomMiddle = CGPointMake(x+(width/2),y+height+addWH);    CGPoint bottomLeft   = CGPointMake(x,y+height);            CGPoint leftMiddle = CGPointMake(x-addWH,y+(height/2));        [path moveToPoint:topLeft];    //添加四个二元曲线    [path addQuadCurveToPoint:topRight                 controlPoint:topMiddle];    [path addQuadCurveToPoint:bottomRight                 controlPoint:rightMiddle];    [path addQuadCurveToPoint:bottomLeft                 controlPoint:bottomMiddle];    [path addQuadCurveToPoint:topLeft                 controlPoint:leftMiddle];    //设置阴影路径     _imageView1.layer.shadowPath = path.CGPath;

ok！