CODEWITHSUNDEEP
iosswiftbackground-process
Sultan Ali
Sultan Ali

Reputation: 2589

Running an application in background with playing some audios and accelerometer

I am stuck a point from days. Basically, i am developing an application which play some audios to guide user (user can not control these audios no play/pause) and with paying audios it also using accelerometer to get data and calculate some results from this data with regular interval. Means i am playing some audios and then start accelerometer about 4 times alternatively
Every thing is working as expected but when application enters into background application is kept alive for some time and the OS terminate/kill application.
Basically this whole flow take about 6 to 7 minutes at-least meaning that my application needed to alive in background mode at-least 7 minutes. I have seen stackOverFlow questions but not success.
What i am using when user start

self.backgroundTaskID = UIApplication.shared.beginBackgroundTask (withName: "Finish Network Tasks") {
            // End the task if time expires.
            UIApplication.shared.endBackgroundTask(self.backgroundTaskID!)
            self.backgroundTaskID = UIBackgroundTaskIdentifier.invalid
            
        }
        
        self.startForFirsPhase()

When first phase over I start second phase and third phase after end of previous

and code to play audios is blow

func play(name: String, volumeLevel: Float? = 1) {
    //        print("NameForAudio: ", name)
        guard let path = Bundle.main.path(forResource: name, ofType: nil) else {
            print("can not find path")
            return
        }
        let url = URL(fileURLWithPath: path)
        do {
            try AVAudioSession.sharedInstance().setCategory(.playback)
            try AVAudioSession.sharedInstance().setActive(true, options: .notifyOthersOnDeactivation)
            self.audioPlayer = try AVAudioPlayer(contentsOf: url)
            self.audioPlayer.volume = volumeLevel ?? 1
            self.audioPlayer!.play()
        } catch {
            print("some thing went wrong Name: \(error)")
        }
}

all the audios are liked with the accelerometer I play some audio after one an other using DispatchQueue.main.asyncAfter(deadline: .now() + durationOfPreviousAudio)

What i am trying to do is. I play some audios one after another then start accelerometer to get some motion sensor data for 1 minute and then i again want to play some audio after that which do not play without UIApplication.shared.beginBackgroundTask.

Upvotes: 2

Views: 233

Answers (2)

matt
matt

Reputation: 535925

this whole flow take about 6 to 7 minutes at-least meaning that my application needed to alive in background mode at-least 7 minutes

You can’t do it. There is no iOS feature that permits an app to stay active in the background for 7 minutes to read the accelerometer. You need to change your spec to accommodate reality.

Upvotes: 1

Rob Napier
Rob Napier

Reputation: 299595

You don't need (and should not use) beginBackgroundTask for this. That is an hint to the system that you're beginning a short-lived task that, should the app go into the background before the task is ended, would benefit by getting a little extra time to complete. This is used for things like saving data to the file system or finishing a network operation.

"Background Process" is a completely different tool, used for long-running utility processes such as optimizing databases or running learning algorithms. You should not use that for this.

If you're playing background audio, then you must use the background audio mode. See the linked docs on how to configure this, and how to control background audio. (You have likely already checked the correct configuration box in Xcode, but you also need to make sure you've configured and activated an AVAudioSession that matches your use case. You likely want .playback and may want .mixWithOthers.) It generally needs to continuously play. You cannot easily start audio at an arbitrary time in the future, for example.

You likely will also benefit from enabling background location events.

There is no general-purpose "run in the background" tool in iOS. There are several specialized tools for solving specific problems, and you need to use ones that match your use case. Background operations are complex in iOS, and you'll want to read the documentation on each tool you use to see how to configure it and what it does and doesn't allow.

Upvotes: 1

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