How to Password protect iOS app file?

Question

I have an app where people could enter sensitive personal information. Is there a reasonable method to protect this from - even family access?

Answer 1

At the very first launch of your App, ask a user to create a password, save it somewhere, then on each launch after the first, bring up a modal view controller with a UITextField and set the secureTextEntry property to YES (myPasswordTextField.secureTextEntry = YES;) and do not dismiss the modal view until the password matches one that has been previously set.

Apple Modal View Controllers Example
UITextField Docs
UITextInputTraits Docs