Question

I want to mimic what seem to be the standard UI for using the UISearchBar, and right now I trying to make the rest of the view gray, when I begin searching, and I tried doing that by just setting the background color of the view to gray, but I am using sections in my UITableView, and they are not turning gray. Anybody have any reasons why that is?

Answer 1

The reason you’re not seeing the section headers fade to gray is because they are drawn on top of the gray background, and are opaque; in other words, their alpha is 1.

If you’re looking for a suggestion to get the effect you want, my first reflex would be to add an overlay UIView as a subview of the area you want to be “grayed out”, and change its background color when certain events occur. Something like this:

// You have to choose what view is the one that needs to be grayed out.
// I'll call the view you want to gray out "viewToBeGrayed"

UIView *grayOverlay = [[UIView alloc] initWithFrame:viewToBeGrayed.frame];

// Initially, the overlay should be clear
[grayOverlay setBackgroundColor:[UIColor clearColor]];

[viewToBeGrayed addSubview:grayOverlay];

Then, when you want to “gray out” viewToBeGrayed, just change the background color of grayOverlay to some translucent gray value:

[grayOverlay setBackgroundColor:[UIColor colorWithWhite:0.5 alpha:0.5]];

Finally, when you want to get rid of the “grayed out” effect, just set the view back to clear:

[grayOverlay setBackgroundColor:[UIColor clearColor]];

That should be a good place to start. Comment if you need any additional help.