Placeholders

Placeholders gives you the ability to define multiple placeholders for UITextField, and also animate their change in the way you like. The result looks like that:

You can read more about the library on Medium.

Usage

1. Define a `Placeholder` object in your view controller:

let placeholders = Placeholders(placeholders: ["First", "Second", "Third"])

If you want to loop placeholders (make the set infinite):

let placeholders = Placeholders(placeholders: ["First", "Second", "Third"], options: .infinite)

If you also want to show them in a random order:

let placeholders = Placeholders(placeholders: ["First", "Second", "Third"], options: [.infinite, .shuffle])

2. In your `viewWillAppear` method, call `.start`:

placeholders.start(interval: 3.0,
                   fireInitial: true,
                   textField: textField,
                   animation: .pushTransition(.fromBottom))

That's it!

Advanced

While being easy-to-use, Placeholders can be highly customized. At it's core, Placeholders object doesn't know anything about UITextField. You can easily use it for other purposes if you wish:

let placeholders = Placeholders(placeholders: ["A", "B", "C"], options: .infinite)
placeholders.start(interval: 2.0, fireInitial: true, action: { next in
    print(next)
})

Actually, the UITextField convenience is just a wrapper around this method.

But if you just want to make a custom animation as, for example, .pushTransition, you can extend UITextField.PlaceholderChange. Here is how you can implement your own custom fade animation:

extension UITextField.PlaceholderChange {
    
    static var fade: UITextField.PlaceholderChange<Placeholder> {
        return UITextField.PlaceholderChange { (placeholder, textField) in
            let transition = CATransition()
            transition.duration = 0.35
            transition.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
            transition.type = kCATransitionFade
            textField.subviews.first(where: { NSStringFromClass(type(of: $0)) == "UITextFieldLabel" })?.layer.add(transition, forKey: nil)
            placeholder.set(on: textField)
        }
    }
    
}

This generic Placeholder type and placeholder.set(on: textField) syntax exists in order to support NSAttributedString as a placeholder.

You can also use convenience .caTransition static function to make your life a bit easier:

extension UITextField.PlaceholderChange {
    
    static var fade: UITextField.PlaceholderChange<Placeholder> {
        return .caTransition {
            let transition = CATransition()
            transition.duration = 0.35
            transition.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
            transition.type = kCATransitionFade
            return transition
        }
    }
    
}

And now you can simply write:

placeholders.start(interval: 3.0,
                   fireInitial: true,
                   textField: textField,
                   animation: .fade)

Neat!

Installation

Placeholders is available through Carthage. To install, just write into your Cartfile:

github "dreymonde/Placeholders" ~> 0.1.0

We also encourage you to write your very own implementation that fits your needs best. Our source code is there to help.

tysonkerridge/Placeholders