custom backspace button crashes iPhone app

Question

I have a custom keyboard and whenever I touch the backspace button for the first time my app crashes! How can I solve this problem?

My code:

 myText.text = [myText.text substringToIndex:([myText.text length]-1)];

Answer 1

Test if the existing text has at least one character for you to trim out...

if ([myText.text length]>0) myText.text = [myText.text substringToIndex:([myText.text length]-1)];