IOS background work

Question

I have an iPhone application like facebook for iPhone. My application must connect my server and read all message every two hours regularly. I have a thread to read all message but when the application is terminated the thread cannot work. Can the thread run undependently from main delegate or how can I find solution for this problem?

Answer 1

You cannot have your app do stuff in the background. There is an API to finish tasks like uploading a photo but even that will be killed after around 10 minutes.

But the Apple Push Notification Service seems like the most appropriate solution for your problem. Your server notifies the device that there is something new happening and you fetch the actual messages when the user opens the app.

edit: As of iOS 7 Apple implemented a feature where you can schedule running tasks to fetch data in the background. Those tasks are not guaranteed to run at any specific times. See the release notes for iOS 7 and the linked methods below:

Apps that regularly update their content by contacting a server can register with the system and be launched periodically to retrieve that content in the background. To register, include the UIBackgroundModes key with the fetch value in your app’s Info.plist file. Then, when your app is launched, call the setMinimumBackgroundFetchInterval: method to determine how often it receives update messages. Finally, you must also implement the application:performFetchWithCompletionHandler: method in your app delegate.