NEW: Subscribe to Hacking with Swift+ and accelerate your learning! >>

How to register a cell for UITableViewCell reuse

Swift version: 5.2

Paul Hudson    @twostraws   

Reusing table view cells has been one of the most important performance optimizations in iOS ever since iOS 2.0, but it was only with iOS 6.0 that the API got cleaned up a little with the addition of the register() method.

There are two variants to register, but both take a parameter called forCellReuseIdentifier, which is a string that lets you register different kinds of table view cells. For example, you might have a reuse identifier "DefaultCell", another one called "Heading cell", another one "CellWithTextField", and so on. Re-using different cells this way helps save system resources.

If you want to use register() with a Swift class, you provide a table view cell class as its first parameter. This is useful if your cell is defined entirely in code. As an example, this uses the default UITableViewCell class:

tableView.register(UITableViewCell.self, forCellReuseIdentifier: "DefaultCell")

The other option is to use register() with an Interface Builder nib file, like this:

tableView.register(UINib(nibName: "yourNib", bundle: nil), forCellReuseIdentifier: "CellFromNib")

Regardless of which option you choose, you can dequeue your cells like this:

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "DefaultCell")!
    return cell
}

If there aren't any cells created that can be reused, iOS will automatically create them – this API really is very easy.

Although knowing the above code is definitely useful, if you're using storyboards you will find it easier to create prototype cells and give them a reuse identifier directly inside Interface Builder.

Hacking with Swift is sponsored by NSSpain

SPONSORED Announcing NSSpain 2020: Remote Edition! An online, continuous conference for iOS developers. We’ll start on Thursday and finish on Friday, with talks, activities, and lots of fun for 36 hours, non-stop. Sound good? Join us!

Find out more

Sponsor Hacking with Swift and reach the world's largest Swift community!

Available from iOS 6.0 – see Hacking with Swift tutorial 33

Similar solutions…

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.

BUY OUR BOOKS
Buy Pro Swift Buy Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift (Vapor Edition) Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Advanced iOS Volume Three Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with macOS Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Server-Side Swift (Kitura Edition) Buy Beyond Code

Was this page useful? Let us know!

Average rating: 4.2/5

Link copied to your pasteboard.