Dequeuing Cells the Easy Way

2019-04-10T14:22:49+00:00

How many times have you done something like this:

let cell = tableView.dequeueReusableCell(withIdentifier: "EventCell",
    for: indexPath) as! EventCell

The typo-prone string identifier, the forced cast… surely we can do better with Swift?

Let’s add a couple of useful extensions to UITableView and its descendants:

extension NSObject {
    class var className: String {
        return NSStringFromClass(self).components(separatedBy: ".").last!
    }
}

extension UITableView {
    func dequeueCell<T>(for indexPath: IndexPath) -> T where T: UITableViewCell {
        return dequeueReusableCell(withIdentifier: T.className, for: indexPath) as! T
    }
    func dequeueCell<T>() -> T? where T: UITableViewCell {
        return dequeueReusableCell(withIdentifier: T.className) as? T
    }
}

This makes the assumption that the cell’s reuse identifier is identical to its class name.

Now, thanks to Swift’s type inference, all we need to do to get a cell of the correct type is:

let cell: EventCell = tableView.dequeueReusableCell(for: indexPath)

My First Post

2019-04-08T13:51:49+00:00

You’ll find this post in your _posts directory. Go ahead and edit it and re-build the site to see your changes. You can rebuild the site in many different ways, but the most common way is to run jekyll serve, which launches a web server and auto-regenerates your site when a file is updated.

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  puts "Hi, #{name}"
end
print_hi('Tom')
#=> prints 'Hi, Tom' to STDOUT.

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markiv’s blog

Dequeuing Cells the Easy Way

My First Post