Question

I am trying to add a bunch of UIButton to a horizontal UIScrollView using the following code, however I am not seeing anything and all I see is just a white UIScrollBar. Why is this? I am pretty sure that I messed up something as before it was just working just fine.

self.category = [[NSArray alloc]initWithObjects:@"ALL", @"FOOD",@"NIGHT LIFE",@"ARTS & ENTERTAINMENT",@"SPORT", @"SHOP", @"COLLEGE & UNIVERSITY", @"TRAVEL SPOT", nil];
self.scrollView.delegate = self;
    self.scrollView.scrollEnabled = YES;
    self.scrollView.autoresizingMask = YES;

    int xOffset = 0;

    for(int index=0; index < [self.category count]; index++)
    {
        UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
        [button.titleLabel setTextAlignment:UITextAlignmentCenter];
        [button setBackgroundImage:[UIImage imageNamed:@"CategoryTab.png"] forState:UIControlStateNormal];
        [button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
        [button setTag:index];
        [button addTarget:self action:@selector(pressed:) forControlEvents:UIControlEventTouchUpInside];
        [button setTitle:[self.category objectAtIndex:index] forState:UIControlStateNormal];
        [button setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
        [button.titleLabel setFont:[UIFont fontWithName:@"bebas" size:15.0]];
        CGSize maximumLabelSize = CGSizeMake(300,9999);
        CGSize expectedLabelSize = [[self.category objectAtIndex:index] sizeWithFont:[UIFont fontWithName:@"ArialMT" size:15.0]                     
                                      constrainedToSize:maximumLabelSize 
                                          lineBreakMode:UILineBreakModeWordWrap];
        [button setFrame: CGRectMake(xOffset, 0, expectedLabelSize.width + 30, 38)];
        [self.scrollView addSubview:button];
        xOffset += expectedLabelSize.width + 30;
        [button release];
    }
     self.scrollView.contentSize = CGSizeMake(xOffset, 38);

Answer 1

A few possible causes :

• The UIButton is released once too often. It’s created autoreleased, then added to the scrollview, then released, which effectively means it will be dealloc’d when the autorelease pool ends. I’m surprised this does not crash, actually. Are you using Automatic Reference Counting?
• is self.scrollview correctly initialized? If it’s nil, it will simply fail silently.
• is the “bebas” font really loaded and available? Custom font loading isn’t that trivial on iOS.

Also :

• You’re not using the actual button font to measure the label size. (“bebas” vs “ArialMT”)
• you probably have a leak on line 1. That NSArray would better be autoreleased ( using[NSArray arrayWithObjects:...]).
• autoresizingMask is not a BOOL value, it’s an OR combination of flags.