A view with a shadow

Question

enter image description here

I am looking for the way to write an effect like the image above (from the Groupon app) for a view. Using the code below, I tried to get a shadow going, but it's not working. The effect I am looking for is the view getting darker from top to bottom. Can anybody tell me what I've done wrong, and how to get closer to the effect Groupon gets?

   view.layer.shadowColor           =   [[UIColor blackColor] CGColor];
   view.layer.shadowRadius          =   8.0f;
   view.layer.shadowOpacity         =   0.75f;
    UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:view.bounds cornerRadius:4.0];
   view.layer.shadowPath            =   path.CGPath;

I dont know why I am getting down vote. Just try to learn something new — tranvutuan, Mar 03 '13 at 21:54
Because you haven't even tried to implement it yourself (or as far as we can tell, you haven't). Show us some code before you go asking us to do it all for you. — CodaFi, Mar 03 '13 at 21:58
thanks for that. one more thing I am concerning is that I am not sure `view.layer.shadowpath` is the right tool to achieve what I am looking for. — tranvutuan, Mar 03 '13 at 22:06
What shadow are you talking about? The only shadow I see is on the strikethrough line of $29.99. — jscs, Mar 03 '13 at 22:10
@JoshCaswell I believe he's talking about that "fade-to-black" effect in the background view. — CodaFi, Mar 03 '13 at 22:11
It sounds like you after [setting a gradient](http://stackoverflow.com/a/844801/620197) for the `UIView`'s background, rather than a shadow. The code you posted would create a drop shadow. — Mike D, Mar 03 '13 at 23:50

score 3 · Accepted Answer · answered Mar 03 '13 at 23:50

The effect you're looking for is called a gradient. (In iOS terms, a shadow is a duplicate of some object, blurred, tinted and offset.)

You can use a CAGradientLayer to get the kind of effect you're looking for; try adding one of these as a sublayer of your view.

score 0 · Answer 2 · answered May 20 '13 at 04:02

Just to reiterate Jesse Rusak's solution above, in your UIView's Drawrect you create a gradient from clear to black and add it to your view's sublayer:

- (void)drawRect:(CGRect)rect {
    CGContextRef context = UIGraphicsGetCurrentContext();
    UIColor * darkerColor = [UIColorcolorWithWhite:0.0alpha:0.5];
    CGContextSetFillColorWithColor(context, darkerColor.CGColor);
    CGContextFillRect(context, self.bounds);
    NSArray *colors = [NSArrayarrayWithObjects:
                   ((id)[self.backgroundColorcolorWithAlphaComponent:0.0f].CGColor),
                   ((id) [UIColorcolorWithWhite:0.0alpha:1.0].CGColor), nil];
    gradientLayer = [[CAGradientLayeralloc] init];
    gradientLayer.startPoint = CGPointMake(0.5, 0);
    gradientLayer.endPoint = CGPointMake(0.5,1);
    gradientLayer.frame = self.frame;
    gradientLayer.colors = colors;
    [self.layerinsertSublayer:gradientLayeratIndex:0];
}

A view with a shadow

2 Answers2