Run app for more than 10 minutes in background - ios

I am trying to keep the iOS app in active state for more than 10 mins when it enters in background state.
How can I implement this.

See "Background Execution" section of the iPhoneAppProgrammingGuide. In short, your app must be one of these types:
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
And you must add to the Info.plist as follows:
Add the UIBackgroundModes key to your
Info.plist file and set its value to an array containing one or more of the following strings:
audio—The app plays audible content to the user while in the background. (This content includes streaming audio or video content using AirPlay.)
location—The app keeps users informed of their location, even while it is running in the background.
voip—The app provides the ability for the user to make phone calls using an Internet connection.
newsstand-content—The app is aNewsstand app that downloads and processesmagazine or newspaper
content in the background.
external-accessory—The app works with a hardware accessory that needs to deliver updates on a
regular schedule through the External Accessory framework.
bluetooth-central—The app works with a Bluetooth accessory that needs to deliver updates on a
regular schedule through the CoreBluetooth framework
Note that part of the review process will be checking to make sure that your app does what it says it's doing with regard to background processing.

Here's what I've done using beginBackgroundTaskWithExpirationHandler.
Write a method that starts a background task.
Inside that background task, run a NSTimer with a scheduled (non repeating) time that is under 10 minutes. For the purposes of my situation I was using 5 minutes.
Once the NStimer's selector fires, end the background task and then instantly call the method that you wrote earlier to start off another background task.
If you want to schedule methods to run at specific times, you will have to check for them in the background task.
This solution isn't really ideal and is still power hungry but will do what you want.
Edit: Since iOS7, I suggest you read this excellent post. Note that this article was last updated in 2013 and is probably irrelevant now.

Only certain types of apps are allowed to run in the background. See the "Implementing Long-Running Background Tasks" section of this guide.
If you aren't requesting permissions to do background processing you can use UIApplication's beginBackgroundTaskWithExpirationHandler but you cannot get extra time.

This code makes your iOS app run indefinitely in the background. Copy and paste the below methods into a singleton / manager which handles the tasks you need to perform in the background.
// #interface
// Declare Private property
#property (nonatomic) UIBackgroundTaskIdentifier backgroundTask;
//#end
// ...
// Copy into
//#implementation
- (void)setupBackgrounding {
[[NSNotificationCenter defaultCenter] addObserver: self selector: #selector(appBackgrounding:)
name: UIApplicationDidEnterBackgroundNotification
object: nil];
[[NSNotificationCenter defaultCenter] addObserver: self selector: #selector(appForegrounding:)
name: UIApplicationWillEnterForegroundNotification
object: nil];
}
- (void)appBackgrounding: (NSNotification *)notification {
[self keepAlive];
}
- (void) keepAlive {
self.backgroundTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
[[UIApplication sharedApplication] endBackgroundTask:self.backgroundTask];
self.backgroundTask = UIBackgroundTaskInvalid;
[self keepAlive];
}];
}
- (void)appForegrounding: (NSNotification *)notification {
if (self.backgroundTask != UIBackgroundTaskInvalid) {
[[UIApplication sharedApplication] endBackgroundTask:self.backgroundTask];
self.backgroundTask = UIBackgroundTaskInvalid;
}
}

You can't. Unless your app uses audio, voip or gps. What you can do is notify the user (via local notifications) that the time is almost up and ask him to open/close the app.
Also if you just need to notify the user, you can use push notifications.

https://github.com/yarodevuci/backgroundTask Check my code here I am using audio player that plays blank wav file Works perfectly on IOS 8 Battery usage around 10% in 24 hour period
How to use:
var backgroundTask = BackgroundTask()
backgroundTask.startBackgroundTask() //Starts playing blank audio file. You can run NSTimer() or whatever you need and it will continue executing in the background.
backgroundTask.stopBackgroundTask() //Stops the task
Warning: Apple will reject this if you try to submit it!

If your App type is not one of VOIP/Audio/Location....(check Background Modes),
or you don't want to specify your App as a background App, you can implement beginBackgroundTaskWithName:expirationHandler or beginBackgroundTaskWithExpirationHandler to ask for more time to run your process in background. You can find the detailed description here
Apps moving to the background are expected to put themselves into a quiescent state as quickly as possible so that they can be suspended by the system. If your app is in the middle of a task and needs a little extra time to complete that task, it can call the beginBackgroundTaskWithName:expirationHandler: or beginBackgroundTaskWithExpirationHandler: method of the UIApplication object to request some additional execution time. Calling either of these methods delays the suspension of your app temporarily, giving it a little extra time to finish its work. Upon completion of that work, your app must call the endBackgroundTask: method to let the system know that it is finished and can be suspended.
Each call to the beginBackgroundTaskWithName:expirationHandler: or beginBackgroundTaskWithExpirationHandler: method generates a unique token to associate with the corresponding task. When your app completes a task, it must call the endBackgroundTask: method with the corresponding token to let the system know that the task is complete. Failure to call the endBackgroundTask: method for a background task will result in the termination of your app. If you provided an expiration handler when starting the task, the system calls that handler and gives you one last chance to end the task and avoid termination.

Related

UIApplication. Background execution for a fixed amount of time

So, i want my app to do background execution for only a fixed amount of time, this is in case the user does not manually stop the app, and the app therefore in theory could run in background forever(is that even possible?).
I'm using the code below (just a test app) to test how long exactly a background task can run before ending. I read somewhere that 10 minutes is the longest we can do background execution, and there is no way to get beyond that(?). However, my code will only execute in the background for 3 minutes.
So to sum up my questions:
Is it possible to tell the app to execute in the background for x > 10 minutes?
2.Do i have any other options for something similar? (the actual app i need this implemented in, receives location updates in the background, the user could have the phone in the background for as long as 30 minutes, and suddenly not receiving updates would be bad)
- (void)viewDidLoad {
[super viewDidLoad];
counterTask = [[UIApplication sharedApplication]
beginBackgroundTaskWithExpirationHandler:^{
// do something }];
count=0;
theTimer=[NSTimer scheduledTimerWithTimeInterval:0.1
target:self
selector:#selector(countUp)
userInfo:nil
repeats:YES];
}
- (void)countUp {
if (count==10000) {
[theTimer invalidate];
[[UIApplication sharedApplication] endBackgroundTask:counterTask];
} else {
NSLog(#"asd");
count++;
NSString *currentCount;
currentCount=[[NSString alloc] initWithFormat:#"%d",count];
_theCount.text=currentCount;
long seconds = lroundf([[UIApplication sharedApplication] backgroundTimeRemaining]);
NSLog([NSString stringWithFormat:#"%ld",seconds]);
}
}
I read somewhere that 10 minutes is the longest we can do background execution, and there is no way to get beyond that(?). However, my code will only execute in the background for 3 minutes.
yes you are right before iOS 7 iOS allowed 10 minutes max for apps to execute in background , however since iOS 7 they have reduced this time to 180 seconds.
But if you want to get Location Updates in background than you can add Required Background modes property in your info.Plist file. Using this you will be able to run your app in background for getting location updates Apple will review your request while reviewing your app for app store submission so be sure to use this mode only if you using it for its actual purpose.
Following are various modes for which apple allows background execution you can take a look at it at Apples Doc on background execution
Edit
If you wish to stop getting location Updates after specific time once user goes to backGround you can do this
- (void)applicationDidEnterBackground:(UIApplication *)application {
[self performSelector:#selector(stopGettingLocationUPdates) withObject:nil afterDelay:1800];
}
-(void)stopGettingLocationUPdates{
[self.locationManager stopUpdatingLocation]
}
This will stop updates after 30 mins.
Your code is not running in the background. It is not testing what you want to test.
Apple's docs say:
Executing a Finite-Length Task in the Background Apps that are
transitioning to the background can request an extra amount of time to
finish any important last-minute tasks. To request background
execution time, call the
beginBackgroundTaskWithName:expirationHandler: method of the
UIApplication class.
The actual time you get is not specified and is probably decided ad hoc based on power consumption, memory needs and so on. They may be a maximum.
They go on to say:
Implementing Long-Running Background Tasks For tasks that require more
execution time to implement, you must request specific permissions to
run them in the background without their being suspended. In iOS, only
specific app types are allowed to run in the background:
Apps that play audible content to the user while in the background, such as a music player app
Apps that record audio content while in the background.
Apps that keep users informed of their location at all times, such as a navigation app
Apps that support Voice over Internet Protocol (VoIP)
Apps that need to download and process new content regularly
Apps that receive regular updates from external accessories
Apps that implement these services must declare the services they support and use system frameworks to implement the relevant aspects of
those services. Declaring the services lets the system know which
services you use, but in some cases it is the system frameworks that
actually prevent your application from being suspended.

Execute function every X minutes in background doesn't work

I use this code to execute function every X minutes:
- (void)executeEveryOneMinute
{
[self myFunction];
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(60 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[self executeEveryOneMinute];
});
}
And it works when app is in foreground.
But when app goes background it doesn't work anymore.
When I return app to foreground again it execute function once.
And continue to call function every minute again.
So how to make this to work in background too?
See the Background Execution and Multitasking section of the iOS App Programming Guide: App States and Multitasking for a discussion of the possibilities. You can, for example, keep the app running in the background for a few minutes in order to complete some finite length task. Or you can continue to run the app in the background for a longer period of time if it's performing one of a very particular list of functions (quoting from the aforementioned document):
Apps that play audible content to the user while in the background, such as a music player app
Apps that record audio content while in the background.
Apps that keep users informed of their location at all times, such as a navigation app
Apps that support Voice over Internet Protocol (VoIP)
Apps that need to download and process new content regularly
Apps that receive regular updates from external accessories
Apps that implement these services must declare the services they support and use system frameworks to implement the relevant aspects of those services. Declaring the services lets the system know which services you use, but in some cases it is the system frameworks that actually prevent your application from being suspended.
But, a fundamental design principle in iOS battery/power management is that random apps can not (and should not) continue to run in the background. If you share what precisely you're trying to do (namely, what precisely you're doing inside that executeEveryOneMinute method), though, we can offer counsel on how to achieve the desired effect, if possible.
If you're trying to have an upload continue in the background, in iOS 7 and greater, you should consider using NSURLSession with a background session configuration ([NSURLSessionConfiguration backgroundSessionConfiguration:identifier]; there is a similar method in iOS 8). This will continue to attempt to upload (automatically, without further intervention on your part) not only after your app has left the foreground, but even after the app is terminated (e.g. due to memory pressure or a crash). AFNetworking offers a NSURLSession-based class, AFURLSessionManager, which supports this (though it's not NSOperation-based). This way, you enjoy background uploads, but conforms to Apple guidelines on background operation, notably with less dramatic battery impact than retrying yourself every 60 seconds.
I'd suggest you refer to the latter part of WWDC 2013 video What’s New in Foundation Networking, which demonstrates this process (they're doing a download, but the idea is the same for uploads).
Timer works on Main thread. When application goes into background, its timers become invalid. So, you cant do the same when application goes into background.
You can't do this with help of timer as it will be invalidated in background. You can try check this.
You should use background tasks to achieve what you want
UIApplication* app = [UIApplication sharedApplication];
task = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:task];
task = UIBackgroundTaskInvalid;
}];
// Start the long-running task and return immediately.
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// Do the work associated with the task.
NSLog(#"Started background task timeremaining = %f", [app backgroundTimeRemaining]);
if (connectedToNetwork) {
// do work son...
}
[app endBackgroundTask:task];
task = UIBackgroundTaskInvalid;
});

iOS 7 Background Modes - Not For App Store (No Rules Apply)

For the bounty, I am not interested in GPS or audio background modes as the former uses too much of the battery and the latter prevents any other audio from being used, otherwise facing audio interruption, thus ending background processes. I will need a way to be continuously processing in the background, so background modes that trigger occasionally are also out of the question.
If there is some way to run the application in the background, even by ignoring Apple's rules, I am interested in trying it. If the answer is VOIP, I am unsure where to begin the implementation, as all of my research has come up too high level or as a failure. How will my application be able to run in the background using the VOIP background mode. Without any added code, the application refuses to run in the background.
I know that with iOS 7, background modes have changed again. I would like to be able to run my application (that will never need to be approved on the iOS App Store) in the background. I would also like to be able to stop execution in the background until a specific time in the future.
For example, I would like it to run a process for 15 minutes, schedule the next task and then sleep until that time. For now, I've had to run a silent track in the background for background processing, but I would like to be able to have the application truly sleep during that time - also, playing real music or making a phone call are "handy features" of the iPhone and I don't like losing them.
I know there is also GPS, but that consumes an enormous amount of battery. The other background modes don't seem to give full control of background processing and timing to the application and leave a large portion of the timing and execution duration to the OS.
What I need is to be able to have my application process in the background for minutes at a time and then sleep until a fairly specific interval and continue processing. Is this possible with a better approach than I am currently using?
I've seen that VOIP used to be a possibility, but I'm not sure that it will work, as I don't need the application to run one simple task in the background, but rather to continue whatever was running in the foreground before the application was pushed to the background. Also, individual tasks could take upwards of 1 hour to complete, so they won't be able to transfer when the background task expires. All of my assumptions are based off this thread.
Edit: There seems to be a terrible drop off rate with this method. At random, the recursion will seemingly fail for seemingly no reason (maybe a system timeout on execution?). If I place the recursion before ending the background task, the OS kills my application, but if I put it after, it occasionally seems to stop the background tasks at some point. I have seen it stop in the middle of my "allotted background time", as well.
In short, the below method does seem to run indefinitely, but not infinitely. Is there either a way to make the runtime guaranteed to be infinite or another solution?
It seems that using VOIP was leagues easier than I had first thought.
All that is required to run my application indefinitely (unfortunately sleeping is not an option) is to add voip to the selected Background Modes, either in the plist or in Target's Capabilities. After that, adding and running this code once, in an object that is never deallocated (your AppDelegate works nicely here), will allow for infinite background processing time:
- (void)infiniteBackgroundLoop
{
__block UIApplication *applicationBlockReference = [UIApplication sharedApplication];
__block AppDelegate *appDelegateBlockReference = self;
__block UIBackgroundTaskIdentifier backgroundTask = [applicationBlockReference beginBackgroundTaskWithExpirationHandler:^
{
[applicationBlockReference endBackgroundTask:backgroundTask];
backgroundTask = UIBackgroundTaskInvalid;
[appDelegateBlockReference infiniteBackgroundLoop];
}];
}
In order to allow sleeping indefinitely, add a break to the recursion.
I used background fetch to achieve something similar.
You can use this to keep your app active in the background.
I have the a demo, see if it helps you:
Add these properties to your .h file -
#property (nonatomic, strong) NSTimer *updateTimer;
#property (nonatomic) UIBackgroundTaskIdentifier backgroundTask;
Now suppose you have a action on button --> btnStartClicked then your method would be like :
-(IBAction)btnStartClicked:(UIButton *)sender {
self.updateTimer = [NSTimer scheduledTimerWithTimeInterval:0.5
target:self
selector:#selector(calculateNextNumber)
userInfo:nil
repeats:YES];
self.backgroundTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
NSLog(#"Background handler called. Not running background tasks anymore.");
[[UIApplication sharedApplication] endBackgroundTask:self.backgroundTask];
self.backgroundTask = UIBackgroundTaskInvalid;
}];
}
-(void)calculateNextNumber{
#autoreleasepool {
// this will be executed no matter app is in foreground or background
}
}
and if you need to stop it use this method,
- (IBAction)btnStopClicked:(UIButton *)sender {
[self.updateTimer invalidate];
self.updateTimer = nil;
if (self.backgroundTask != UIBackgroundTaskInvalid)
{
[[UIApplication sharedApplication] endBackgroundTask:self.backgroundTask];
self.backgroundTask = UIBackgroundTaskInvalid;
}
i = 0;
}
We also played with background modes in our app, and I check all solution that found, and can say that there is only one way to stay active in background and is not "VOIP", because "VOIP" gives your app wake-up every 5-6 minutes not infinity run.
In documentation about setKeepAliveTimeout:handler: you can see that this method will call handler block at minimum every 600 second, and block has a maximum of 10 seconds to perform any needed tasks and exit.
To clean this you can add NSLog(#"time remain: %f", [[UIApplication sharedApplication] backgroundTimeRemaining]); to your infiniteBackgroundLoop implementation. Because second and next call beginBackgroundTaskWithExpirationHandler not get same time of background run as first call.
Another working way is Location Manager, yes is bad because use lot of battery but is get you that you want - app newer stop.
The implementation can be easily found there
You could use background fetch and set the regresh rate to a short NSTimeInterval.
In your didFinishLaunchingWithOptions: try to add:
[[UIApplication sharedApplication] setMinimumBackgroundFetch:1];
I haven't tested this, let me know if this could be a starting point.

how much time UIApplication is going to run in the background state

plz help me out how much time UIApplication is going to run in the background state.like when we press home button etc
Limitation is as following:
10 mins for iOS6
3 mins for iOS7
Just in your app delegate implement:
- (void)applicationDidEnterBackground:(UIApplication *)application {
UIApplication *app = [UIApplication sharedApplication];
__block UIBackgroundTaskIdentifier bgTask = 0;
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
}
After 600s (iOS6) or 180 s (iOS7) the expiration handler is called - you have to finish immediately - no chance for any time consuming task or app will crash.
I suggest you to take a look at Background Execution and Multitasking, briefly:
Most apps are moved to the suspended state shortly after entering the
background. Only apps that provide important services to the user are
allowed to continue running for any amount of time
It runs something like 5 seconds.
You can also do a special process to ask more time to end a long task (like upload etc..).
Everything is explained here : https://developer.apple.com/library/ios/documentation/iphone/conceptual/iphoneosprogrammingguide/ManagingYourApplicationsFlow/ManagingYourApplicationsFlow.html
Have a nice reading session :)
The app is in the background and executing code. Most apps enter this state briefly on their way to being suspended. However, an app that requests extra execution time may remain in this state for a period of time. In addition, an app being launched directly into the background enters this state instead of the inactive state. For information about how to execute code while in the background, see “Background Execution and Multitasking.”
Edited:
Support for some types of background execution must be declared in advance by the app that uses them. In Xcode 5 and later, you declare the background modes your app supports from the Capabilities tab of your project settings. Enabling the Background Modes option adds the UIBackgroundModes key to your app’s Info.plist file. Selecting one or more checkboxes adds the corresponding background mode values to that key. Table 3-4 lists the background modes you can specify and the values that Xcode assigns to the UIBackgroundModes key in your app’s Info.plist file.

What is the proper way to handle background tasks in iOS

I have a voip app and it needs to run in the background. To my understanding these are the things I need to do:
Flag the app as voip.
Set the 'application does not run in background' flag to NO.
Set an expiration handler, a piece of code that extends the standard 10 minutes of execution time you get.
More?
I set both flags in the info.plist file and I get my 10 minutes. I tried what is suggested in this post. Here is my code:
//in didFinishLaunchingWithOptions:
expirationHandler = ^{
NSLog(#"ending background task");
[[UIApplication sharedApplication] endBackgroundTask:bgTask];
NSLog(#"restarting background task");
bgTask = UIBackgroundTaskInvalid;
bgTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:expirationHandler];
NSLog(#"finished running background task");
};
//in applicationDidEnterBackground
NSLog(#"entering background mode");
bgTask = UIBackgroundTaskInvalid;
bgTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:expirationHandler];
// Start the long-running task and return immediately.
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// inform others to stop tasks, if you like
[[NSNotificationCenter defaultCenter] postNotificationName:#"MyApplicationEntersBackground" object:self];
//this while loop is just here for testing
inBackground = true;
while (inBackground) {
NSLog(#"stayin alive!!"); //this keeps going forever
sleep(10);
}
});
The situation:
I use a third party library that handles the communication with our webservice. The service is a CommuniGate pro server. I receive presence updates (online/offline) and instant messages from contacts via the library. The library is CommuniGate's ximss library, a protocol they made which is similar to xmpp and is used for xml-based sip requests, as well as IM and presence. When the user logs in to the app, he sees his contacts (CmmuniGate friends list) and he can choose to call one. After a ximss verification message has been sent and the other side accepted the call it logs the start time of the call and starts a facetime call.
The problem:
When the app enters the background by pressing the home button, I start seeing the 'stayin alive' message in the log and every ten minutes I see that it restarts the background task.
When the app enters the background by pressing the power button, the 'staying alive' messages start showing up for ten minutes, after that it restarts the background task and start restarting it about every 50-100 miliseconds.
I would've been fine with this for now, even it eats battery, because I have time to work on updates and our users don't own the ipads, we do. The problem for me now is that the ximss library loses it's connection (it is session-based). I could restart the session in the library, but this means quite a bit of data transfer to fetch the contacts list and some users use 3g.
I can't edit the library's source, nor can I see it, so I don't know if it creates the sockets the right way.
What do I have to do to handle both situations correctly? I don't even understand why there is a difference.
You cannot re-extend background tasks like this; your app is likely to be terminated. If this is working, it's because you have the background voip mode enabled, not because you are restarting the background task.
Once you have set the voip plist entry, iOS will attempt to keep your app alive as long as possible and restart it if it does get terminated. From Implementing a VoIP App:
Including the voip value in the UIBackgroundModes key lets the system
know that it should allow the app to run in the background as needed
to manage its network sockets. An app with this key is also relaunched
in the background immediately after system boot to ensure that the
VoIP services are always available.
In addition to setting this key, if you need to periodically run code to keep your voip connection alive, you can use the setKeepAliveTimeout:handler: method on UIApplication.
See also Tips for Developing a VoIP App:
There are several requirements for implementing a VoIP app:
Add the UIBackgroundModes key to your app’s Info.plist file. Set the value of this key to an array that includes the voip string.
Configure one of the app’s sockets for VoIP usage.
Before moving to the background, call the setKeepAliveTimeout:handler: method to install a handler to be
executed periodically. Your app can use this handler to maintain its
service connection.
Configure your audio session to handle transitions to and from active use.
To ensure a better user experience on iPhone, use the Core Telephony framework to adjust your behavior in relation to cell-based
phone calls; see Core Telephony Framework Reference.
To ensure good performance for your VoIP app, use the System Configuration framework to detect network changes and allow your app
to sleep as much as possible.
Almost all of the documentation you need is on the Apple developer site.

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