Question

I have looked around for ways to detect when the delete key is pressed. I came across Apple’s key handling documentation and also some people trying this with work arounds. I am not sure which method to pursue. What I want to do is very simple:

-(void)deleteKeyWasPressed {

if (myTextField.text.length == 0) {

[previousTextField becomeFirstResponder]; 

}

}

But as far as I know this method does not exist.

What would be the best way of doing this?

Answer 1

iOS has no direct support for detecting the delete key (or any key other than Return). The best you can do is implement the textField:shouldChangeCharactersInRange:replacementString: delegate method. When the user taps the Delete key, the replacement string will be the empty string.

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    if (string.length == 0) {
        // handle Delete (but this also handles the Cut menu as well)
    } else {
        // some other key or text is being pasted.
    }

    return YES;
}