Detect backspace Event in UITextField

Question

I am searching for solutions on how to capture a backspace event, most Stack Overflow answers are in Objective-C but I need on Swift language.

First I have set deleg

Answer 1

I prefer subclassing UITextField and overriding deleteBackward() because that is much more reliable than the hack of using shouldChangeCharactersInRange:

class MyTextField: UITextField {
    override public func deleteBackward() {
        if text == "" {
             // do something when backspace is tapped/entered in an empty text field
        }
        // do something for every backspace
        super.deleteBackward()
    }
}

The shouldChangeCharactersInRange hack combined with an invisible character that is placed in the text field has several disadvantages:

• with a keyboard attached, one can place the cursor before the invisible character and the backspace isn't detected anymore,
• the user can even select that invisible character (using Shift Arrow on a keyboard or even by tapping on the caret) and will be confused about that weird character,
• the autocomplete bar offers weird choices as long as there's only this invisible character,
• Asian language keyboards that have candidate options based on the text field's text will be confused,
• the placeholder isn't shown anymore,
• the clear button is displayed even when it shouldn't for clearButtonMode = .whileEditing.

Of course, overriding deleteBackward() is a bit inconvenient due to the need of subclassing. But the better UX makes it worth the effort!

And if subclassing is a no-go, e.g. when using UISearchBar with its embedded UITextField, method swizzling should be fine, too.