How to detect delete key on an UITextField in iOS 8?

Question

I have subclassed UITextField and implemented the UIKeyInput protocol's deleteBackward method to detect backspace being pressed. This works fine on iOS 7 but not on iOS 8.

deleteBackward is not called on the UITextField anymore when I press the backspace key.

I've checked the documentation and the release notes and nothing points to the reason why this could happen. Any pointers?

Answer 1

You must look an example for MBContactPicker on github. Deletion of contacts at MBContactPicker via Backspace button on iOS8 tested by me. And it works greatly! You can use its as example.

Author of MBContactPicker use next method: When UITextField must become empty (or before call becomeFirstResponder when it is empty), he save single whitespace symbol there. And then when you press Backspace button (when focus was set to end of text of your UITextField), method

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string

will work. Inside it you must use check like this:

NSString *resultString = [textField.text stringByReplacingCharactersInRange:range withString:string];
BOOL isPressedBackspaceAfterSingleSpaceSymbol = [string isEqualToString:@""] && [resultString isEqualToString:@""] && range.location == 0 && range.length == 1;
if (isPressedBackspaceAfterSingleSpaceSymbol) {
    //  your actions for deleteBackward actions
}

So, you must always control that UITextField contains single whitespace.

This is not hack. So, user willn't noticed about some behaviour was changed