Failed to obtain a cell from its DataSource

Using Swift 3 I encountered this error when I forgot to add the UITableViewDataSource and UITableViewDelegate protocols to the ViewController declaration.

class DataViewController: UIViewController, UITableViewDataSource, UITableViewDelegate

Adding them fixed the problem.

Swift 3.0

You just need to add UITableViewDelegate and UITableViewDataSource

import UIKit

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource

Below image is just for your reference.

Your error suggests that cellForRowAtIndexPath is returning nil for some reason, and I'm guessing it's because you are failing to dequeue a reusable cell. If you want to confirm this, just set a breakpoint after your current dequeue call: I expect you'll find cell is set to nil.

If you're using modern Xcode templates where you get a prototype cell made for you, you should probably be using this instead:

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];

If you aren't using an Xcode template, use that line of code anyway then register your own re-use identifier like this:

[self.tableView registerClass:[UITableViewCell self] forCellReuseIdentifier:@"Cell"];

All being well that should resolve the problem. I wrote this up in more detail for Swift users.