This is a passcode view controller that you're free to use in your own iPhone apps. I developed it for "mappiness":http://www.mappiness.org.uk/.

See it in action by "downloading the free app":http://itunes.apple.com/gb/app/mappiness/id385082965?mt=8 -- and signing up -- or by checking out this "short screencast":http://blog.mackerron.com/2011/10/passcode-view-controller/.

Appearance and behaviour is modelled very closely on the Apple original (in Settings > General > Passcode Lock), but there are a couple of optional, tasteful enhancements:

An incorrect passcode causes the entry screen to shake/shiver a little, just like the Mac OS X log-in dialogue does.

You can set an increasing delay period after several incorrect passcode attempts, to slow down anyone who's just guessing.

h2. Screenshot

!http://blog.mackerron.com/wp-content/uploads/2011/10/photo.png(PasscodeViewController screenshot)!

h2. Example usage

The controller can be used as follows.

h3. .h

<pre><code> #import "PasscodeViewController.h" typedef enum { PasscodeChallengeReasonProtectedAction, PasscodeChallengeReasonTurnOffPasscode } PasscodeChallengeReason; @interface MyController : SomeViewController <UIActionSheetDelegate, PasscodeViewControllerDelegate> { PasscodeChallengeReason challengeReason; } @end </pre></code>

h3. .m

<pre><code> // PasscodeProtectedCellController delegate - (void)doProtectedAction { challengeReason = PasscodeChallengeReasonProtectedAction; [PasscodeViewController challengeWithDelegate:self parentViewController:self]; } - (void)showPasscodeOptions { BOOL locked = !! [PasscodeViewController passcode]; UIActionSheet *as; NSString *sheetTitle = @"Control access to (protected action)"; NSString *cancelLabel = @"Cancel"; if (locked) as = [[UIActionSheet alloc] initWithTitle:sheetTitle delegate:self cancelButtonTitle:cancelLabel destructiveButtonTitle:nil otherButtonTitles:@"Change Passcode", @"Turn Passcode off", nil]; else as = [[UIActionSheet alloc] initWithTitle:sheetTitle delegate:self cancelButtonTitle:cancelLabel destructiveButtonTitle:nil otherButtonTitles:@"Turn Passcode on", nil]; [as showInView:self.view]; // might alternatively be self.tableView [as release]; } // UIActionSheetDelegate - (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex { if (buttonIndex == 0) // i.e. 'Turn Passcode on' or 'Change Passcode' [PasscodeViewController setWithDelegate:self parentViewController:self]; else { // must be 'Turn Passcode off' challengeReason = PasscodeChallengeReasonTurnOffPasscode; [PasscodeViewController challengeWithDelegate:self parentViewController:self]; } } // PasscodeViewController delegate - (void)passcodeChallengeSucceeded { if (challengeReason == PasscodeChallengeReasonProtectedAction) { // do the passcode-protected action } else { // by elimination, we know that challengeReason == PasscodeChallengeReasonTurnOffPasscode // so turn the passcode off... [PasscodeViewController clear]; // ...and now do any necessary display changes to indicate that a passcode is no longer set } } - (void)passcodeSetSucceeded { // do any necessary display changes to indicate that a passcode is set } </pre></code>

h3. Notes

• All public-facing methods are class methods. These deal with allocating an instance, and instances release themselves when finished.
• If a challenge is requested when no passcode is set, no prompt is shown and the @passcodeChallengeSucceeded@ delegate method is called immediately.
• Automatic Reference Counting (ARC) is not used.

h2. Suggested enhancements

These things are all currently missing:

• Support for iPad
• Support for localisation (using a @.strings@ file)
• Localisations
• More/better documentation!
• Consistent use of Title Case (I hate title case. But I Want To Do What Apple Would Do. This is probably the leading cause of mental anguish when I do iOS development.)

h2. Licence

This software is released under the "MIT licence":http://www.opensource.org/licenses/mit-license.php.