When iPhone application go to applicationWillResignActive mode, I need to download the data from specific site continuously(Using Timer) and if any data receive from that site should push the UILocalNotification. But if App has enter into Background, Downloading functions is not calling. Exactly i want as Mail app.
You can't do that unless you're a VoIP app or a GPS app.
For other types of app, the closest you can do is request the 10 minute long task completion mode. That'll give you ten minutes of running whatever you want in the background, after which the system kills your app.
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I need to build an app that can take in a user audio input and process it even if the phone is in sleep mode. For example, if a user says "Hello", then app needs to recognize that and process it even if the phone is in sleep mode. I have read posts that explain how to prevent a phone from going into sleep mode and that would be my second option if the app cannot read the audio input while the phone is in sleep mode.
I'm afraid that's not possible, there are 5 different types of apps that can keep on running on the background, these are (from the Apple documentation):
Apps that play audible content to the user while in the background, such as a music player app
Apps that keep users informed of their location at all times, such as a navigation app
Apps that support Voice over Internet Protocol (VoIP)
Newsstand apps that need to download and process new content
Apps that receive regular updates from external accessories
if your app is not doing any of these, your app will not execute code when it goes onto the background. Also, you should declare that your app is performing one of these functions before sending it to Apple for review.
I want to update my sqlite database in my iPhone app in every 2 hrs from the server.
Is there any way to call web services from the background even the app is not active?
You can't do this. The best you can do is sync when the app starts up. And if its backgrounded, you wait until they bring it to the foreground and can sync if it's been longer than 2 hours since the app was last in the foreground.
Apple won't let you do these battery draining and CPU stealing things. And really, you don't even need to. If your app isn't using the data, then it doesn't need to be up to date.
You can't run your app in background for doing this. You're app is only allows to run in background for doing Audio Playback, VoIP and Task Completion (till 10min after going to background). But you could do the update once in 2hours when the user starts the app? doing something with push notification to inform the user? But you can't just run something every two hours in background.
I have an iphone app that has a 30second process that does some network IO. Basically, while the app is in the background, i want this process to run every hour (actually once a day, but if it fails i want it to re-run in an hours time).
With the background features of ios 4, is this possible? If so, how? What are the limitations that i'll come up against?
Thanks so much!
Take a look at Apple's documentation about running code in the background.
http://developer.apple.com/library/ios/#documentation/iphone/conceptual/iphoneosprogrammingguide/BackgroundExecution/BackgroundExecution.html
There are few different ways of approaching backgrounded tasks. The only apps that can have fully backgrounded processes are "audio", "voip" and "location" apps, and this needs to be declared in the Info.plist.
If your app is not of this type, you'll probably find it difficult to do what you want easily. There are methods which allow you to keep your app alive in the background for a finite period of time (also at that link), but eventually your app will be shut down.
Local Notifications will only prompt the user to open the app - do you really want to have an alert pop-up on the phone every 30 seconds?
I was making some kind of similar research, have a look at this SO answer in case you didn't manage to find it before. Applications like DataMan or Data Usage must have some sort of periodic code execution in the background, so I'm not 100% convinced that what you're asking for is impossible..
I believe that Using Local notifications will help....
check following....
http://developer.apple.com/library/ios/#documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/IPhoneOSClientImp/IPhoneOSClientImp.html#//apple_ref/doc/uid/TP40008194-CH103-SW1
An application can create and schedule a local notification, and the operating system then delivers it at the schedule date and time. If it delivers it when the application is not active in the foreground, it displays an alert, badges the application icon, or plays a sound—whatever is specified in the UILocalNotification object. If the application is running in the foreground, there is no alert, badging, or sound; instead, the application:didReceiveLocalNotification: method is called if the delegate implements it.
The delegate can inspect the properties of the notification and, if the notification includes custom data in its userInfo dictionary, it can access that data and process it accordingly. On the other hand, if the local notification only badges the application icon, and the user in response launches the application, the application:didFinishLaunchingWithOptions: method is invoked, but no UILocalNotification object is included in the options dictionary.
I'm thinking in making an app that send e-mails without showing the native iOS mail app. For that I'd be using sksmtpmessage framework.
I'd like as well to keep sending the e-mail when the app goes in background. According to this thread, it would be doable.
I know that Apple limits a few tasks to be done is the background (Audio, VoIP and location). Then my question is, would Apple reject an app using sksmtpmessage framework to send an e-mail from the background?
Cheers :)
If you're just "completing a task" (i.e. the user loads the app to send some e-mails, then quits before they're all sent), you're fine - that's what the Task Completion multitasking mode is for. If you want to run constantly in the background sending e-mail, then it'll almost certainly be a reject (if they spot it) - this isn't something they envisage being done on the iPhone.
From the app docs : An application can call the beginBackgroundTaskWithExpirationHandler: method to ask the system for extra time to complete some long-running task in the background. If the request is granted, and if the application goes into the background while the task is in progress, the system lets the application run for an additional amount of time instead of suspending it. (The backgroundTimeRemaining property of the UIApplication object contains the amount of time the application has to run.)
You can do preceding in time, because iOS 4 gives you a 10 mins of time for task completion after you exit an app.
I can't seem to find a clear answer to this-- I'm spec'ing out an iPhone app that I'd like to have live in the background and notify the user at certain periods throughout the day. So the user would launch the app in the morning and then continue to use their phone, then every few hours the app would pop open a notification dialog.
Will my app ever be shut down (automatically) by the OS? Or will it just live forever, notifying user when it needs to?
thanks,
Eric
Basically there are three kinds of running in the background on iOS 4:
Running in the background to "finish" stuff (e.g. upload a posting or a picture, finish processing something etc.). You ask the OS to grant you extra time after the user switches to another app, and it will tell you how much time you got. You can't run in the background for an indefinite time.
Running in the background to do specific stuff: VoIP, tracking location (e.g. for GPS navigation), or playing audio. You can only do the stuff that you told the OS you would do in the background.
Local notifications (UILocalNotification). From your description, this is what you're looking for. You're not actually running, you just schedule notifications, and when it's time to notify the user, they'll be notified and can go to your app. If you need to notify the user dynamically (i.e. you don't know ahead at what times they need to be notified and it's not location or VoIP triggered), you might want to look into push notifications.
Apple has a good overview here:
https://developer.apple.com/documentation/uikit/app_and_environment/scenes/preparing_your_ui_to_run_in_the_background/about_the_background_execution_sequence