This question might be duplicate of many others but I am still asking because I really need to get any solution of it.
For iOS versions prior to 6, for devices other than those having an A7 chip.
I have an application which interacts with the Accelerometer. I am also running it in background by playing a sound file and turning the Audio services ON for background task.
Now If any third application plays music, it takes control of shared Audio Session of device which causes my background thread to call completion handler assuming that background task has been completed.
Now my application is interruptible by iOS and iOS can kill it if it remains in background for a long time after which I couldn't interact with accelerometer.
Is there any way/trick/hack to keep my application running all the time until unless I kill it by my own.
Again, this is a duplicate question but I really wanted to share my problem with you people to help me in this sense.
Apple is very clear on this:
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
Collecting accelerometer data is not listed. Therefore, what you are trying to do is not possible. "Ways, tricks, hacks" tend to get discovered quickly and offending apps removed from the App Store.
Related
I have a VPN-Client app that asks the user to pause the connection for 5, 30, and 120 Minutes. The user probably leaves the application to do some work outside of my app in this period, therefore I need to Reconnect the app even if is in the background.
I tested these ways:
UIApplication.shared.beginBackgroundTask: It only leaves the app unsuspended for 30 seconds.
DispatchQueue.global(qos: .background).asyncAfter: It waits to app enter the foreground to toggle.
Thread.sleep in Background Thread: This waits to launch as DispatchQueue
Local Notification: Unfortunately it does not support silent mode as APNS.
My problem with possible ways:
Using APNS and Scheduled Push Notification` to send a silent message: This way probably works, but I prefer to handle it without a server.
Using Background Fetch from Capabilities in Background Modes: I searched a lot about this, and I think it was used for background app refresh and cycling tasks that should be run every day, hour, etc. Therefore, my case can't be used, or it's not efficient at all.
Using Background processing from Capabilities in Background Modes: I searched a lot about this too, I didn't quite catch that it can be used once, or this should be used in a cyclic way as Background Fetch. and my task to reconnect is not that heavy and long to use this strict feature that many times apple mentioned using alternative ways if possible.
Apple only allows a very limited set of app types to run in the background:
Music streaming apps, turn-by-turn navigation apps, VoIP apps, and maybe one or 2 more. (I haven't looked at this in detail for a couple of years so my info is a little stale.)
They do support various tasks like background downloading that the system performs on your app's behalf, but you want your app to re-launch after the designated period and start running again. (Even if the user just locks their phone while your app is paused, the app won't get any CPU time and may be terminated without warning.)
In short, I suspect you are out of luck.
It seems like a VPN app is another class of app that should get "always running in the background" status.
If you are a licensed Apple developer I suggest using one of your pre-paid support tickets to ask about OS support for what you are trying to do, but I have a feeling the answer is going to be "no dice."
I'm new to iOS development and I'm using Swift in my current project.
I'm trying to achieve something similar I did in Android. I'm trying to run a background service when the app is closed/minimised that will get executed every 2 seconds to keep the user informed that the app is still running in the background and checking for status with the server.
How can I achieve that? I've tried using the "background fetch" method but it doesn't get executed every 2 seconds.
The background service will run no longer than 5 minutes if it matters.
No you can't do that. What you can do is, call a service in applicationDidEnterBackground that lets your server know that your app is in background or killed(You will get very less time for this to get executed, approx. 3-5 sec.).
An Android app like the one you described will likely drain the device’s battery prematurely. This is the simple reason why Apple has restricted background execution to a clearly defined set of tasks:
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
This list is taken from Apple’s official description of background tasks: Background Execution.
What is iOS' alternative to Android AlarmManager class?
So far the closest thing that I found is NSTimer. But that works only when your application is up, once it goes to the background it won't work, and I need to run some function in the background and from my business logic to decide if I want to do something or not. For example if some condition is satisfied to display local notification.
The only workaround I found is to use remote pushing notifications (silent notifications) just to wake up app, and from there you can implement your business logic.
IMPORTANT NOTE
From what I have found on few places is that people are complaining about using silent notifications to do this because your application might be rejected on app store.
There is none.
As already stated in the comments, the documenation is quite clear on that:
Always try to avoid doing any background work unless doing so improves the overall user experience. An app might move to the background because the user launched a different app or because the user locked the device and is not using it right now. In both situations, the user is signaling that your app does not need to be doing any meaningful work right now.
with the following exceptions:
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
There is no exact equivalent. Please read this: https://developer.apple.com/library/ios/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/BackgroundExecution/BackgroundExecution.html
The relevant part:
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.
If the function you are trying to call does one of the above, the documentation explains how to use background tasks or other methods to accomplish that.
I want my iOS apps to run continuously in background 24/7
I tried many options like background location updated with background task expiration handler, but later after some times it seems that the application gets suspended in background and user is brought back to the root view controller.
Any help will be appreciated.
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
Ap ps 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.
You should read this page of Apple Programming Guide : Background Execution
It is not allowed to run background tasks 24/7. But you can use many different ways.
You simply can't. Apple don't give any mean for an app to ensure background execution. iOS will give you processing time whenever it feel like it, and you cannot control that.
I was trying to run some services in the background so I struck the control in the background by using a while(1) loop in the background delegate for some time.
On the emulator it is working fine but on transfering it to my iPad, the app is crashing after going into the background.
Does the while(1) loop not work for on the device?
On emulator it is working fine but on transfering it to the Ipad device , the app is getting crashed after going in to the background.
If I interpret correctly this that you are writing, what I think is that your app gets killed on iOS devices simply because you are not allowed, except in a few spare cases, to run a thread in your app when the app is "in background" (i.e., after the user has "quit" it by clicking on the home button).
So, if I am right in my reading what is happening, either your app is in a specific class of
apps (see later), or the only thing you can do is "registering" a background thread to run for a limited amount of time after the app goes in the background.
Excerpt from Background Execution and Multitasking
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.
As much as possible, you are encouraged to avoid executing in the background and let your app be suspended. If you find you need to perform background tasks, here are some guidelines for when that is appropriate:
You need to implement at least one of several specific user services.
You need to perform a single finite-length task.
You might be especially interested in the "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 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