Cocoa Touch - Keyboard Capturing

Question

How can I tell what keys the user pressed into a textView?

And before you ask since it sounds similar to a keylogger, I'm making a typing app and I need to know if what they entered of the correct matching key to what they were prompted.

Thanks!

Answer 1

You should set the delegate of the UITextView to one of your classes. (in IB or programmatically, does not matter)

In your delegate, you can put the following function, or something similar:

-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range
                  replacementText:(NSString *)text
{
    if ( [text length] == 0 ) return YES; // always allow deletion of characters

    NSString *new = [textView.text stringByReplacingCharactersInRange:range
                                                           withString:text];

    if ( [new length] > 100 ) // PUT IN YOUR MAGIC CONDITION HERE
    {
        return NO; // don't allow the edit to happen
    }

    return YES; // by default, allow the edit to happen
}

this will only limit input to 100 chars, but you can make it as complicated as you see fit.

edit ps, you asked "what key the user pressed", but since we also have copy&paste and auto-correction, this may give a text which is longer than 1 char!