How are functions in table view controllers called? - ios

Question

I am a new to iOS development using Swift.
I am trying to understand how functions are called in a view controller that controls a table view.
In the examples I am looking at, the view controller runs three functions, all called 'table view', and each function does something unique such as returning how many rows are in a section, or using reusable cells.
But I just can't see when or how these functions are called.
Are they called when the user navigates to the view? If so, how? And how come these different functions all have the same name (i.e. func tableView ())?
Here is some sample code:
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return dwarves.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell = tableView.dequeueReusableCellWithIdentifier(simpleTableIdentifier)
as? UITableViewCell
if (cell == nil) {
cell = UITableViewCell(style: UITableViewCellStyle.Subtitle, reuseIdentifier: simpleTableIdentifier)
}
cell!.textLabel.text = dwarves[indexPath.row]
cell!.textLabel.font = UIFont .boldSystemFontOfSize(15)
return cell!
}

Answer 1

I just can't see when or how these functions are called.
A UITableView calls these methods on its delegate or dataSource to get information about what it should display, and communicate when certain actions occur. For a UITableViewController, the controller itself is both the delegate and the data source. So you won't see these methods get called unless you set a breakpoint within them.
Are they called when the user navigates to the view? If so, how?
When the user navigates to the view, the default implementation of UITableViewController sets the table view's delegate and data source properties to self. The table view itself calls these methods lazily when it needs information to create, size, layout, and display table cells appropriately.
And how come these different functions all have the same name? I.e func tableView ()
They don't. In both Swift and Objective-C, argument names are part of the method name. For example, this method:
func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
return 80
}
is named tableView(_:heightForRowAtIndexPath:).