Question

Using the notification center, as described in How can I get a textDidChange (like for a UISearchBar) method for a UITextField?, allows you to get a notification when text in an iOS UITextField changes. I didn’t see a similar notification for selection changes. What’s the best way to detect and respond to changes in the selection for a UITextField?

Answer 1

Wire up a method using target/action to the UIControlEventEditingChanged control event on your instance of UITextField. This can be done in the interface builder or in code by adding a target/action pair to the text field and then implementing the specified method.

[self.textField addTarget:self action:@selector(textFieldTextChanged:) forControlEvents:UIControlEventEditingChanged];

UITextField also declares a UITextFieldDelegate protocol with methods that you can implement in your class to be notified of changes to an instance of UITextField. I recommend that you become comfortable with delegation as it is a common pattern in the Cocoa framework.

UITextFieldDelegate Class Reference