Adding a subview larger than cellHeight to a UITableViewCell?

Question

I'm trying to add a subview to a UITableViewCell and the design that I'm working from demands that this particular subview (an image) needs to be larger than the actual UITableViewCell and thus partly overlap its siblings.

So I've set up my table cell, generated my image and added it to the cell's contentView:

// rowHeight for the UITableView is 45.0f

UIImage *image = [self createCellThumbnail: someImage];
UIImageView *thumbView = [[UIImageView alloc] initWithFrame: CGRectMake(150, -5, 55,55)];
thumbView.transform = CGAffineTransformMakeRotation(0.1f);
thumbView.image = image;

cell.clipsToBounds = NO;
cell.contentView.clipsToBounds = NO;

[cell.contentView addSubview: thumbView];

While the image will 'overflow' into the cell below it, the top of the image is always clipped, as demonstrated here: http://imgur.com/WDsAx .

Does anyone know if what I'm trying to do is possible with the current approach?

Or should I just figure out a way to draw these images onto the UITableView after all the cells are drawn (it's a non-scrollable tableview, so that would work and be fairly easy).

Update:

Have also tried adding the following, to no avail:

cell.opaque = NO;
cell.contentView.opaque = NO;

cell.clearsContextBeforeDrawing = NO;
cell.contentView.clearsContextBeforeDrawing = NO;

cell.clipsToBounds = NO;    
cell.contentView.clipsToBounds = NO;

Answer 1

I actually had the opposite just yesterday, I had created a custom table cell and for some reason I got an overflow which I didn't want to have. My solution was to add the following code to my view controller class:

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{  
    return 175;
}

When it matched the height of the table cell there was no overlap; when it was too small there was overlap. Mind you though that I got very quicky behavious so I'm not sure it's a very good idea to do this.

Answer 2

I seems that the tableView renders it's cell from bottom to top, so the cells above one cell overlap that one cell. To avoid this, you'd have to set the backgroundColor of all cells to +[UIColor clearColor] so that you won't see those overlap problems.

But setting the backgroundColor to clear in -tableView:cellForRowAtIndexPath: does not make any sense. UIKit does a lot of stuff with the cell before it's drawn, so does it reset the backgroundColor property of the cell.

What we need to do is setting the backgroundColor in a later state. Luckily there is this -[UITableViewDelegate tableView:willDisplayCell:forRowAtIndexPath:] which we can implement like this:

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
    cell.backgroundColor = [UIColor clearColor];
}

Now we're setting the backgroundColor just before the cell is drawn an this turns out to be working.