Question

I’m trying to implement a UIScrollView in each cell of `UITableView’. I wrote my code based on Apple’s custom Scrollview project: https://developer.apple.com/library/ios/#samplecode/Scrolling/Listings/ReadMe_txt.html

Each table cell’s UIScrollView scrolls through a set of labels, which are initialized in the cellForRowAtIndexPath method. Each label’s text is set after initialization to equal a string from an array.

Everything works correctly until I scroll down to the 4th table cell. The UIScrollView in this cell has the same exact labels as the first cell. The same first 3 set of labels or the first 3 scrollViews keep repeating after the first 3 cells. The strange part is, when I log the label.text after it is set, the output shows the correct label.text of what should be displaying in the respective cell.

- (void)layoutScrollLabels: (float)arrayCount
{
UIView *view = nil;
NSArray *subviews = [cell.popularLinkScrollView subviews];

// reposition all image subviews in a horizontal serial fashion
CGFloat curXLoc = 0;
for (view in subviews)
{
    if ([view isKindOfClass:[UILabel class]] && view.tag >= 0)
    {
        CGRect frame = view.frame;
        frame.origin = CGPointMake(curXLoc, 0);
        view.frame = frame;

        curXLoc += (kScrollObjWidth);
    }
}

[cell.popularLinkScrollView setContentSize:CGSizeMake((arrayCount * kScrollObjWidth),     [cell.popularLinkScrollView bounds].size.height)];

}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Custom Cell";

cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
    cell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}

NSDictionary *dictionary = [parseDataArray objectAtIndex:indexPath.row];
NSArray *popularLinkTitleArray = [dictionary objectForKey:@"popularLinkTitleArray"];

cell.popularLinkScrollView.clipsToBounds = YES;

kScrollObjHeight = cell.popularLinkScrollView.frame.size.height;
kScrollObjWidth = cell.popularLinkScrollView.frame.size.width;

NSUInteger i;
for (i = 0; i < popularLinkTitleArray.count; i++)
{
    NSString *string = [NSString stringWithFormat:@"%@", [popularLinkTitleArray objectAtIndex: i]];
    UILabel *label = [[UILabel alloc] init];
    label.text = [NSString stringWithFormat:@"%@", string];
    label.backgroundColor = [UIColor clearColor];
    label.numberOfLines = 5;
    NSLog(@"%@", label.text);

    // setup each frame to a default height and width, it will be properly placed when we call "updateScrollList"
    CGRect rect = label.frame;
    rect.size.height = kScrollObjHeight;
    rect.size.width = kScrollObjWidth;
    label.frame = rect;
    label.tag = i;  // tag our images for later use when we place them in serial fashion
    [cell.popularLinkScrollView addSubview:label];
}

[self layoutScrollLabels:popularLinkTitleArray.count];
}
return cell;
}

Answer 1

You should not add label as a subview to popularLinkScrollView in cellForRowAtIndexPath. If the count of labels is required to be dynamic, try this code before your for loop in cellForRowAtIndexPath.

for (UIView* subView in cell.popularLinkScrollView.subviews)
    [subView removeFromSuperview];