Ios – UITableView with static cells without cellForRowAtIndexPath. How to set clear background

As I understand it, you want to:

1. Design a cell in IB which can be used in multiple storyboard scenes.
2. Configure unique storyboard segues from that cell, depending on the scene the cell is in.

Unfortunately, there is currently no way to do this. To understand why your previous attempts didn't work, you need to understand more about how storyboards and prototype table view cells work. (If you don't care about why these other attempts didn't work, feel free to leave now. I've got no magical workarounds for you, other than suggesting that you file a bug.)

A storyboard is, in essence, not much more than a collection of .xib files. When you load up a table view controller that has some prototype cells out of a storyboard, here's what happens:

• Each prototype cell is actually its own embedded mini-nib. So when the table view controller is loading up, it runs through each of the prototype cell's nibs and calls -[UITableView registerNib:forCellReuseIdentifier:].
• The table view asks the controller for the cells.
• You probably call -[UITableView dequeueReusableCellWithIdentifier:]

• When you request a cell with a given reuse identifier, it checks whether it has a nib registered. If it does, it instantiates an instance of that cell. This is composed of the following steps:

  1. Look at the class of the cell, as defined in the cell's nib. Call [[CellClass alloc] initWithCoder:].
  2. The -initWithCoder: method goes through and adds subviews and sets properties that were defined in the nib. (IBOutlets probably get hooked up here as well, though I haven't tested that; it may happen in -awakeFromNib)

• You configure your cell however you want.

The important thing to note here is there is a distinction between the class of the cell and the visual appearance of the cell. You could create two separate prototype cells of the same class, but with their subviews laid out completely differently. In fact, if you use the default UITableViewCell styles, this is exactly what's happening. The "Default" style and the "Subtitle" style, for example, are both represented by the same UITableViewCell class.

This is important: The class of the cell does not have a one-to-one correlation with a particular view hierarchy. The view hierarchy is determined entirely by what's in the prototype cell that was registered with this particular controller.

Note, as well, that the cell's reuse identifier was not registered in some global cell dispensary. The reuse identifier is only used within the context of a single UITableView instance.

Given this information, let's look at what happened in your above attempts.

In Controller #1, added a prototype cell, set the class to my UITableViewCell subclass, set the reuse id, added the labels and wired them to the class's outlets. In Controller #2, added an empty prototype cell, set it to the same class and reuse id as before. When it runs, the labels never appear when the cells are shown in Controller #2. Works fine in Controller #1.

This is expected. While both cells had the same class, the view hierarchy that was passed to the cell in Controller #2 was entirely devoid of subviews. So you got an empty cell, which is exactly what you put in the prototype.

Designed each cell type in a different NIB and wired up to the appropriate cell class. In storyboard, added an empty prototype cell and set its class and reuse id to refer to my cell class. In controllers' viewDidLoad methods, registered those NIB files for the reuse id. When shown, cells in both controllers were empty like the prototype.

Again, this is expected. The reuse identifier is not shared between storyboard scenes or nibs, so the fact that all of these distinct cells had the same reuse identifier was meaningless. The cell you get back from the tableview will have an appearance that matches the prototype cell in that scene of the storyboard.

This solution was close, though. As you noted, you could just programmatically call -[UITableView registerNib:forCellReuseIdentifier:], passing the UINib containing the cell, and you'd get back that same cell. (This isn't because the prototype was "overriding" the nib; you simply hadn't registered the nib with the tableview, so it was still looking at the nib embedded in the storyboard.) Unfortunately, there's a flaw with this approach — there's no way to hook up storyboard segues to a cell in a standalone nib.

Kept prototypes in both controllers empty and set class and reuse id to my cell class. Constructed the cells' UI entirely in code. Cells work perfectly in all controllers.

Naturally. Hopefully, this is unsurprising.

So, that's why it didn't work. You can design your cells in standalone nibs and use them in multiple storyboard scenes; you just can't currently hook up storyboard segues to those cells. Hopefully, though, you've learned something in the process of reading this.

As Apple DOC said (UITableViewCell Class Reference):

... In iOS 7, cells have a white background by default; in earlier versions of iOS, cells inherit the background color of the enclosing table view. If you want to change the background color of a cell, do so in the tableView:willDisplayCell:forRowAtIndexPath: method of your table view delegate.

So for my case that to show cells with transparent background, just need to implement the delegate method in the table view controller like below:

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

Just Note: As @null said, "...there seems to be a bug in interface builder...", I'm not totally sure whether it does have the bug, but seems so cause his comment got several up votes. So there might something wrong if you use IB. :)