I know that in iOS, background apps can only be running
Finite-length tasks (10 min)
Location updates
VoIP
Audio
Is there a way for my application to avoid being terminated after being 10 min. in the background? I will not be submitting my app to the app store, so everything is allowed (private frameworks, using the gps even if I don't need it) I know apple does not recommend this, but it is just for monitoring purposes. I need it to be running without a limit.
I explored several possibilities including the VoIP , but it only gives me 30 seconds every 10 minutes, which is not enough. I also read this post:
iPhone - Backgrounding to poll for events
in which JackPearse specified a way to "revive" the 10 minute finite-length task using the VoIP 30 second task. But I don't want my task to start and end every 10 minutes, it must run continuosly.
I also tried his UPDATE2, but it's not working for me.
I even tried intercepting the UIEvent with GSEvent.type 2012, which seemed to be the one ending my background task, but no luck. Strangely, my background task is never ended when I have Xcode opened and debugging, but when I don't (test the simulator alone) it ends after 10 minutes.
I have already tried some way(nsrunloop,*performselectoronmainthread*) like that.It's works well in simulator (not in device because apple crashes automatically after sometimes) when the app goes to background.
status is a BOOL variable.
- (void)applicationDidEnterBackground:(UIApplication *)application {
while (!**status**) {
[[NSRunLoop mainRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:60.0]];
[self goBackground];
}
}
I found out how to keep my Application in the background for longer than 10 minutes by continuously playing a song in the background.
On the AppDidFinishLauching:
[[AVAudioSession sharedInstance] setActive:YES error:&error];
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:&error];
NSURL *url = [NSURL fileURLWithPath:...]; //Song URL
AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error];
player.numberOfLoops = -1;
[player play];
In the AppDidEnterBackground you can perform a selector in background, which can last forever. The App will not be interrupted, you can check UIApplication backgroundtimeRemaining and see it never decreases.
Of course, declare the app as a background audio App in the plist.
Related
Apple resources contain a lot of informations but there's one thing which I can't clearly understand reading about audio and notification.
Is it possible to make an app, running in background which produce sound (even if phone is locked and/or silenced) and when it's happend user must solve eg. equation to turn it off?
p.s. For now I mostly use Cordova framework but Obj-C tip will also be nice.
Yes it is posssible.
You can use UILocalNotification for this.
Also apple allows apps that are playing music in background.
Please check these links for the background task feature:
ManagingYourApplicationsFlow
ios multitasking background tasks
How to handle background audio playing while ios device is locked or on another
You can change Local Notifications for NSTimers (keeping them alive in inactive mode with https://github.com/mruegenberg/MMPDeepSleepPreventer) and calculate the time interval for each alarm. That way you can then play an audio even with the screen locked and the sound off pasting this in your - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions:
// Let the sound run with the screen blocked
NSError *setCategoryErr = nil;
NSError *activationErr = nil;
[[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayback error:&setCategoryErr];
[[AVAudioSession sharedInstance] setActive:YES error:&activationErr];
But you will have some problems:
The app must be playing an audio file each 10 seconds so it doesn´t deep sleep and kills all NSTimers.
Apple could reject your app for doing so.
You can´t close the app with the home button, otherwise, it won´t work.
You must open the app every time you need to use the alarm (you can´t schedule and forget).
When the alarm fires, you only have the lock screen of the iPhone and need to unlock it first and then stop the alarm from inside the app.
In Apple they don´t want competitors for their alarm clock app, that's for sure! Almost all the alarm clock apps you see in the App Store use this poor approach.
I got a need to stop (or mute at least) music/sound that is played in iPhone.
Important: I want my app will do that it even if is in background-state!
I'm using:
[[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategorySoloAmbient error:nil]];
[[AVAudioSession sharedInstance] setActive: YES];
The issue is that everything is being stopped, even streaming music from some other app, but only if app is in FOREGROUND. As wrote before, I want it to be working also in BACKGROUND.
I did simple research and realized it's somehow possible, these apps prove:
App Store - Streaming Music Timer or
App Store - Music Sleep Timer
I guess my solution with SoloAmbient can be not so perfect and it may be a wrong way.
Does anybody know how could I stop/sleep/pause/mute global music even if app will be in background state?
These apps I pointed out are doing basically this thing...
You need to enable the audio background mode.
Add the Required Background Modes key to your app's Info.plist and add the App Plays Audio key to it.
See this tutorial for more.
EDIT Also, you probably want the AVAudioSessionCategoryPlayback category, not AVAudioSessionCategorySoloAmbient
I have an App that does the pretty standard operation:
It plays audio (streamed or in filesystem) when the app is in 1) Foreground mode, 2) Screen locked state 3)Background mode.
This was working fine in all iOS prior to iOS5.
I have been using MPMoviePlayerController (Because it can play streamed and local file system audio)
I have the following setup:
info.plist has Background Mode set to "Audio"
I have Audiosession setup as shown at http://developer.apple.com/library/ios/#qa/qa1668/_index.html
NSError *activationError = nil;
AVAudioSession *mySession = [AVAudioSession sharedInstance];
[mySession setCategory: AVAudioSessionCategoryPlayback error: &activationError];
if (activationError) { /* handle the error condition */ }
[mySession setActive: YES error: &activationError];
if (activationError) { /* handle the error condition */ }
I have background timer enabled that gets stopped at the end of audio playback
UIBackgroundTaskIdentifier newId = [[UIApplication sharedApplication]
beginBackgroundTaskWithExpirationHandler:NULL];
I have the Moveplayer's useApplicationAudioSession = NO
I have subscribed to the following events to detect and handle various playback state and to start a new audio file at the end of current file.
MPMoviePlayerLoadStateDidChangeNotification
MPMoviePlayerPlaybackDidFinishNotification
MPMoviePlayerPlaybackStateDidChangeNotification
MPMoviePlayerNowPlayingMovieDidChangeNotification
Problem:
With this the audio starts to play and when the application is put to background state or if the phone is locked, the audio continues to play. But, after when I start another audio file,
I start getting PlaybackDidFinishNotification immediately with the state set to Playback ended (But the file was never played)
The same code plays audio files in foreground mode (After the current audio file ends, the next file is started without any problem)
Is there anything new in iOS5 I should be doing to get this to work? I read through the MPMoviePlayerController class reference and I couldn't see anything specific for iOS5.
Thanks in advance.
Finally figured out the issue. This is solved in this post in apple dev forums (needs login to see). That post was applicable to AVPlayer but also fixes the problem with MPMoviePlayerController as well.
Basically, this is an excerpt from that post:
your app must support remote control events! These are the audio
controller interface prex/nex/play/pause on the left of the multitask
switcher taskbar (not sure about the proper name of the thing). You
to this ensuring your view becomes First Controller and then calling
> [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
in viewDidLoad. Once you do this, your Player will no longer return
NO!!
My situation was different and I'm only answering here (and in the other SO question) to help future searchers on this error message. This does not answer the original question.
My app plays a sound OR a song but when I first coded it could play both. And in testing I always tested with a song. I played the song in the usual way:
self.musicQuery = [MPMediaQuery songsQuery];
[_musicQuery addFilterPredicate:[MPMediaPropertyPredicate predicateWithValue:selectedSongID forProperty:MPMediaItemPropertyPersistentID comparisonType:MPMediaPredicateComparisonEqualTo]];
[_musicQuery setGroupingType:MPMediaGroupingTitle];
[_myPlayer setQueueWithQuery:_musicQuery];
[_myPlayer play];
Weeks passed and I started testing with the sound, played with AVAudioPlayer. My app started freezing for 5 seconds and I'd get the MediaPlayer: Message playbackState timed out message in the Console.
It turns out that passing a query that was empty was causing the freeze and the message. Changing my app's logic to only play a song when there was a song to play fixed it.
I know that you can for example play music in you app and it would be running in background but it looks like it's not working. I've this code when my application starts on iPhone:
pathToAudio = [[NSBundle mainBundle] pathForResource:#"silence" ofType:#"mp3"];
audioURL = [NSURL fileURLWithPath:pathToAudio];
audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:audioURL error:NULL];
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:NULL];
audioPlayer.numberOfLoops = -1;
[audioPlayer play];
Result is that it plays music when I send app to background but other activities doesnt run. For example in my app I'm listening to socket and although music plays in background my app doesnt respond to incomming messages (it normally responds when app is in foreground). What do I do wrong? I've read that you can do other activities when playing music when app is in background but it looks like it doesn't work...
Edit: I have jailbroken iPhone so any unconventional methods are welcome. I know that Apple would reject my app if I was playing silent audio in background and I dont care about it. I just want to know how to make app running in background when playing music or in any other way... Maybe I need to have iPhone 4? I have iPhone 3G.
Nothing, it's only possible to run audio in background (aside with some special cases like geoloc notifs & VoIP), not other stuff.
You'll need to provide a specification for the info.plist file like the UIBackgroundModes.
My app uses NSTimer and it appears that NSTimer doesn't fire when the iPhone goes into the stand-by mode (either by pressing the hardware button or by the idle timer).
When I activate the iPhone again, my app is still in the foreground. What happens to third party apps when the iPhone is the stand-by mode?
Although it's not evident here, I believe the original poster did find an answer to his question by starting a thread (available here) in the iPhone Developer Forums (which I eventually had to find myself because the information wasn't shared here).
In case someone else has the same question and finds the page in the future, here's a helpful response that was posted by someone on the Apple forum called "eskimo1" (which I have edited slightly such that it is easier to read without having the context provided by the entire original thread):
Regarding iPhone app status terminology, "active" does not mean "awake", it means "attached to the GUI". Think of it being analogous to "frontmost" in Mac OS X. When you lock the device your app deactivates but the device may or may not go to sleep
iPhone OS rarely sleeps if the device is connected to main power (i.e., via USB). It can sleep if running on battery, however.
A short time after the screen is locked (20 seconds according to Oliver Drobnik), the device sleeps. This is like closing the lid on your laptop; all activity on the main CPU halts.
This does not happen if the device is playing audio in the right audio session. See DTS Q&A QA1626 "Audio Session - Ensuring audio playback continues when screen is locked" for details.
Note that the idleTimerDisabled property (which can be turned on to prevent the screen from turning off while the app is running) is about locking the screen after user inactivity. It's not directly related to system sleep (it's indirectly related in that the system may sleep shortly after it's locked).
See Application Interruptions in the iPhone OS Programming Guide, especially the applicationWillResignActive and applicationDidBecomeActive events. (The whole guide is certainly worth reading.) When You ignore the events, the timer seems to go on for a while and then stops. Sounds logical, the application could easily drain the battery if kept running. And what exactly happens to the application? I guess it simply does not get any CPU time – it freezes and only thaws when You turn the machine back “on.”
My first advice is do not disable the idle timer, that is just a hack. If you want to keep a timer alive during UI events run the timer on the current run loop using NSCommonModes:
// create timer and add it to the current run loop using common modes
self.timer = [NSTimer timerWithTimeInterval:.1 target:self selector:#selector(handleTimer) userInfo:nil repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes];
I used the information on this post for a small sample that I was building. This is the code that I used when I initiated the playback to prevent the audio from stopping:
AudioSession.Category = AudioSessionCategory.MediaPlayback;
And when the application is done with the playback to reset to the original value:
AudioSession.Category = AudioSessionCategory.SoloAmbientSound;
The full sample is here:
http://github.com/migueldeicaza/monotouch-samples/tree/master/StreamingAudio/
I was faced with this issue recently in an app I am working on that uses several timers and plays some audio prompts and made two relatively simple changes:
In the AppDelegate I implemented the following methods and there mere presence allows the app to continue when the screen is locked
// this receives the notification when the device is locked
- (void)applicationWillResignActive:(UIApplication *)application
{
}
// this receives the notification that the application is about to become active again
- (void)applicationWillBecomeActive:(NSNotification *)aNotification
{
}
references: UIApplicationDelegate Protocol Reference & NSApplication Class Reference in the API doc (accessible via Xcode, just search for applicationWillBecomeActive).
Made the main viewcontroller class an AVAudioPlayerDelegate and used this code from Apple's "AddMusic" sample to make the audio alerts the app played mix nicely into the iPod audio etc...
I just dropped this code into a method that is called during viewDidLoad. If this interests you, you fall into the "who should read this doc" category for this: Audio Session Programming Guide
// Registers this class as the delegate of the audio session.
[[AVAudioSession sharedInstance] setDelegate: self];
// The AmbientSound category allows application audio to mix with Media Player
// audio. The category also indicates that application audio should stop playing
// if the Ring/Siilent switch is set to "silent" or the screen locks.
[[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryAmbient error: nil];
// Activates the audio session.
NSError *activationError = nil;
[[AVAudioSession sharedInstance] setActive: YES error: &activationError];
I believe your application should run normally when suspended. (think Pandora Radio)
Check to see if your timer is being deallocated due to your view being hidden or some other event occurring.