Why do all backgrounds disappear on UITableViewCell select?

Question

My current project\'s UITableViewCell behavior is baffling me. I have a fairly straightforward subclass of UITableViewCell. It adds a few extra elements to the base view (vi

Answer 1

When you start dragging a UITableViewCell, it calls setBackgroundColor: on its subviews with a 0-alpha color. I worked around this by subclassing UIView and overriding setBackgroundColor: to ignore requests with 0-alpha colors. It feels hacky, but it's cleaner than any of the other solutions I've come across.

@implementation NonDisappearingView

-(void)setBackgroundColor:(UIColor *)backgroundColor {
    CGFloat alpha = CGColorGetAlpha(backgroundColor.CGColor);
    if (alpha != 0) {
        [super setBackgroundColor:backgroundColor];
    }
}

@end

Then, I add a NonDisappearingView to my cell and add other subviews to it:

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *cellIdentifier = @"cell";    
    UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:cellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier] autorelease];
        UIView *background = [cell viewWithTag:backgroundTag];
        if (background == nil) {
            background = [[NonDisappearingView alloc] initWithFrame:backgroundFrame];
            background.tag = backgroundTag;
            background.backgroundColor = backgroundColor;
            [cell addSubview:background];
        }

        // add other views as subviews of background
        ...
    }
    return cell;
}

Alternatively, you could make cell.contentView an instance of NonDisappearingView.