Adding the "Clear" Button to an iPhone UITextField
This button is a built-in overlay that is provided by the UITextField class, but as of the iOS 2.2 SDK, there isn't any way to set it via Interface Builder. You have to enable it programmatically.
Add this line of code somewhere (viewDidLoad, for example):
Objective-C
myUITextField.clearButtonMode = UITextFieldViewModeWhileEditing;Swift 5.0
myUITextField.clearButtonMode = .whileEditing
You can also set this directly from Interface Builder under the Attributes Inspector.
Taken from XCode 5.1
Swift 4+:
textField.clearButtonMode = UITextField.ViewMode.whileEditingor even shorter:
textField.clearButtonMode = .whileEditing