CODEWITHSUNDEEP
iphoneobjective-cios
minovsky
minovsky

Reputation: 857

controlling when app will refresh when returning from background

This is a rather general question on what actually happens when an app returns from background. I have a user telling me that on opening my app that he has not used for over a day, he will still be shown the same view that he had before he closed the app (by "closed" I mean he just hit the home button to send it to background, NOT hold and then tap the cross button to kill the app completely).

I was on the impression that if an app is restored from the background after a long time, it will be reloaded completely (showing splash screen and everything), as in the cases when I opened facebook or gmail app after I haven't used it for some time.

So my question is, do I have to implement a check somewhere on the period of time passed since my app was sent to background and reset everything when it goes over a certain threshold, or is that supposed to be handled by iOS itself... and of course if a user sent my app to the background and return after 2 minutes I would not want to refresh

Upvotes: 2

Views: 2217

Answers (2)

iDev
iDev

Reputation: 23278

You might have to handle that in your appdelegate methods by setting a timestamp. Since multitasking is enabled in iPhones, it will start from the same screen again. An app can be in background for a long time until user decides to kill the app.

Some of the delegate methods are 

- (void)applicationWillResignActive:(UIApplication *)iApplication;
- (void)applicationDidEnterBackground:(UIApplication *)iApplication;
- (void)applicationWillEnterForeground:(UIApplication *)iApplication;
- (void)applicationDidBecomeActive:(UIApplication *)iApplication;

If you want to disable multitasking you can do that by setting a UIApplicationExistsOnSuspend key in application plist. But that will make the app quit immediately when user presses home button.

Upvotes: 2

rmaddy
rmaddy

Reputation: 318914

The decision on whether your app should refresh after some period of time in the background is completely up to you and the needs of your app. An app could sit in the background for weeks without being killed by the OS. Or it could be killed seconds after going into the background. It all depends on resources being needed for other running apps.

If you want logic in your app that makes it restart after 24 hours, for example, then it is up to you to write code to handle this. Save a timestamp when the app goes into the background. When it returns to the foreground, compare the current time to the saved timestamp. If enough time has passed, you need to update your UI to reflect whatever desired state you want to show the user.

Upvotes: 1

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