Question

I have an app with a button in the bottom that i’m creating using a UIButton library, GradientButton (found here: http://code.google.com/p/iphonegradientbuttons/).

I can create buttons fine, but i cannot for the world figure out how to change the colour gradient of the created button after i’ve set the color once…

I tried, as an example, to change the gradient in my button’s actionlistener with various tricks, for example (i’m setting it in viewdidload the first time):

- (IBAction)buttonPressed:(id)sender{
    NSLog(@"buttonPressed;changing style");    
    [checkInCheckOutButton useAlertStyle];//build-in method in gradientbutton that sets colour
    [checkInCheckOutButton setNeedsDisplay];//added this when first didn't work.
}

Am i missing something here? If i change any other, built-in component, say a regular button’s text and/or background, all works fine.

If there’s something i’m not getting regarding how objects are repainted in objective c, i’m all ears…

EDIT: after suggestion, i tried to add some code to alter the color arrays of the button. Unfortunately that didn’t work either:

- (IBAction)buttonPressed:(id)sender{

NSLog(@"buttonPressed;changing style");    
self.checkInCheckOutButton.normalGradientColors = [NSArray arrayWithObjects:[UIColor redColor], [UIColor blueColor], nil];
self.checkInCheckOutButton.highlightGradientColors = [NSArray arrayWithObjects:[UIColor greenColor], [UIColor whiteColor], nil];
[self.checkInCheckOutButton setNeedsDisplay];//tried with and without

Answer 1

I found a solution. Add these lines to the begin of every use...Style method:

normalGradient = NULL;
highlightGradient = NULL;

and add [self setNeedsDisplay]; at the end of these methods.

After these changes it works!