100% opacity UILabel over a 50% opacity background (UIView?)

Question

So right now I have a UIView with a UILabel in it. I want the background to have an opacity < 1.0 and the label to have an opacity of 1.0. However since alphas propagate down the view hierarchy, the label ends up with an opacity < 1.0 as well.

Is there anyway to do what I want without making the UILabel a subview of another view??

Answer 1

Just set the background color to be semitransparent:

view.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.5f]; 

Or, in Swift:

view.backgroundColor = UIColor.blackColor().colorWithAlphaComponent(0.5) 

Or, Swift 3:

view.backgroundColor = UIColor.black.withAlphaComponent(0.5) 

Note that, in this particular case, UIColor(white: 0, alpha: 0.5) is more concise, but colorWithAlphaComponent will work in general.

Answer 2

Besides being available in code, you can do this quite easily from iB as well:

1. Within the storyboard, select the view you wish to edit;
2. From the right panel, make sure the Attributes inspector is opened;
3. Click on the right side of the "Background" drop down box and choose "Other ..."; it will open a colour picker dialog;
4. Change the "Opacity" at the bottom to set the background colour opacity.