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In my iPhone app I want to logout the user if nothing happens till about 2 minutes (e.g. the user puts down the phone). Does anybody has such issue? What is the best way to implement this feature? I think I save the date of last event to NSUserDefaults, then on the next event first I check the current date. If the difference is larger than 2 minutes go to login screen, else refresh the stored date. But how can I get the touch event generally?

Thanks, madik

madik
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2 Answers2

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There's a method in UIApplicationDelegate for that:

- (void)applicationWillResignActive:(UIApplication *)application
{
/*
 Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
 Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
 */
}

Note that it also will be called when the app is going to background state. That will help you store the data whenever the app is going to inactive state. If you want to check if a certain amount of time has passed, you will have to use a NSTimer and store the last touch event. I think it cannot be done because you can't intercept all the touch events (Maybe it's over an object managed by the system. The status bar is an example). I guess is better to let the system to manage all the activity/inactivity stuff and store your data when necessary.

EDIT: I didn't understand what you mean the first time. Check this accepted answer, it accomplish what you need. Basically you have to subclass UIApplication and override sendEvent method.

Community
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Youssef
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  • I think you doesn't understand my question. I know this delegate method, but I don't want to wait till it triggered. Imagine that the user set the auto-lock to 1 hour, but I wan t to logout her/him after 2 minutes inactivity. Or imagine that, the auto-lock is 1 minute. After one minute, the phones lock and it triggers this method. But if the user unlocks the phone and and doesn't elapse two minutes after the last touch, I don't want to show the login screen. My question is how to detect tap events? I know the UIGestureRecognizer delegate, but this is the best way for it? – madik Sep 23 '11 at 14:49
  • Ok, I get it now. I'm updating my answer to show you a couple of solutions I found. – Youssef Sep 23 '11 at 14:57
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'NSTimer'

When you say "how can I get the touch event generally?", if you mean how can you tell if the user is idle or not, you'll have to set up some system to gather all touch events at a higher level in your app. You could update the last touch time you mentioned in NSUserDefaults but that may be inefficient during the run of the app, so you could just post the touch event to your main app delegate and have it save the time of last touch. Which would also be where you could set up the 2 minute timer.

Something like:

- (void) someAppDelegateMethodThatYouCallForAnyUserEvent
{
    [self.idleTimer invalidate];
    self.lastEvent = [NSDate now];
    self.idleTimer = [NSTimer scheduledTimerWithTimeInterval:120 target:self selector:@selector(logoutAndGotoLogin) userInfo:nil repeats:NO];
...
}

You'll also have to do some cleanup in your app delegate methods when the app goes to background etc if you support that behavior.

EricLeaf
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