What's going on with my UIButtons in a xib?

I have a set of UIButtons (defined in a xib) who have labels that need to be updated periodically. In the ViewDidLoad method of the view controller of those buttons' superview, I have an update method that does, for each button:

button.titleLabel.text = @"Relevant Text";
[button setNeedsDisplay];

and when you tap a button, another method runs which pops up a UIAlertView, which in turn calls back a method on the view controller which does much the same thing as the开发者_运维知识库 initial text setting method:

button.titleLabel.text = @"New Text";
[button setNeedsDisplay];

however, this code simply isn't working, the button label's text doesn't get updated in either method, it remains a blank white button. In the xib I don't define any text on the buttons - there's no point, the button text doesn't make sense unless it's set at runtime. Anyway, on a lark, I decided to set the text of one of the buttons to "test test test".

Now, when I tap that particular button, it pops up the UIAlertView but in the background changes the text of the button to "test test test test". And this time, the UIAlertView callback does what I expect it to and sets the text for only that button. When I hit it again, the text goes back to "test test test test" until I dismiss the UIAlertView, which again will run the callback method and set the button text to whatever the method should.

I have no idea what's going on here, or why setting the text initially in the xib has any relation to whether or not I can set that text later programatically. Obviously this isn't the behavior I want, I want to know how to for sure set the text on the buttons.

Edit: SVD's advice about setTitle:ForState: solved my problem, thanks. I'm still curious though as to why the title label set in the .xib shows up, but only when I have a UIAlertView pop up.

You may need to use [setTitle: forState:] to set the button title for normal and highlighted (or selected) state.

(And do make sure the button is connected to the outlet, as jtbandes points out).