I have been looking at the "find my iPhone" app and it seems like it is using iCloud and no push notification to receive a alertView about a notification. By having some mechanism in the background running and alerting the user once it receives a notification.
What I am wondering is that is this app a special exception Apple made for this app, and all other apps have to do push notification? Or can I make an app that runs in the background just like the "find my iPhone" app and communicate via iCloud.
Thank you in advance.
Apple uses iCloud for Find My iPhone, yes, but I believe their reason for this is tying it to your iCloud account so that if your phone is stolen, you can log in your account at icloud.com to attempt to track it. The Find My iPhone app itself works by pinging the GPS location, saving that location, and syncing it with iCloud. For general developer use however, there's no direct API for communicating via iCloud, nor is it likely there will be. iCloud's main purpose is synchronization and backup, and since Apple already has the Push Notification service in place it wouldn't make sense at this point to put that in iCloud. What functionality are you wanting that Apple's Push doesn't allow?
When your app is in the foreground you have the capability of receiving data from an external source a number of different ways. However when your app is terminated either by the user or the system memory watchdog, Push Notifications are the only real route. So at this stage, integrating the APNS is your best solution. There's a few great services that make APNS integration relatively painless, such as Urban Airship.
