i'm building app for listening to acc stream. I m using this library:
https://code.google.com/p/aacdecoder-android/
Especially this player.
PlayerCallback clb = new PlayerCallback() { ... };
MultiPlayer aacMp3Player = new MultiPlayer( clb );
aacMp3Player.playAsync( "http://..." ); // URL of MP3 or AAC stream
It's playing in AsyncTask, but for some smarphones when you put app to backround playing just stop.
Only in methond onDestroy i'm stopping AsyncTask, not in onPause or oStop.
Anyone have an idea why player stops?
Short answer: Music streaming apps need to have a Service running to avoid being terminated by Android.
On a cheaper device or when memory resources run low, Android will simply terminate processes as soon as they go into the background or when more memory is needed. This likely explains why it only happens on "some smartphones" as you mentioned. You can also go into the Developer Options on your phone and play with the "Don't Keep Activities" and "Background process limit" settings to simulate the same thing.
You can read more about how Android prioritizes processes and activities for termination when they are not the active app in the foreground at this link here. You'll read that Services are at higher priority for being kept around than background processes (e.g. Activities that the user exited from, but still have a running thread).
On my music streaming app, when music starts, I start a service (same process as the Activity) and add my app's Main Activity to the Notification area. When the user stops the music, I stop the service and remove the app from the notification area. You'll likely notice very similar behavior between the NPR App, Spotify, i-heart-radio, and others.
Related
I am developing a video call app, and all of my camera, networking, encoding, decoding and audio are running in my activity.
The main problem is that whenever the user locks their screen or switches apps, the activity is shut down and I lose the call.
I've tried wakelocks, notifications, foreground services, nothing keeps my activity alive past Android 10.
Any suggestions?
It is normal for the activity to disappear when the memory is insufficient. You need to use the foreground service to keep the program. Just like the music player, they all use the foreground service.
I am just clearing up my Android doubts. So lets talk about Services, we use services when we have to perform an operation in the background. Lets say Playing Music in the background? Thats one of the most popular reasons why people use Services.
But i just used Mediaplayer in my Mainactivity and i used .start() method in onCreate of my activity. I then minimized the app, but guess what....music still plays. I open the app again, and the music is still playing. I then remove the app from recent apps, basically destroying it and the music stops. Basically the app performs how it is supposed to. Works PERFECT!
Then why do we use services at all for these kind of tasks?
Is there any scenario this code might create a problem? Or is this creating some memory leak or something?
When "minimized" the App continues to play music due to OS delay which allow an User to re-open the App without delay (due to a closure mistake?) because all remained in memory (even the Music) in the previous state.
But the memory is limited, and the CPU the same, so the OS could kill or freeze (using Doze) a background Activity in any moment without prompt User/Developer.
An Activity could be killed to claim Memory or freezed to save CPU cycles. In this situation only explicitely declared Background Services are allowed to run (however with some limitations and special-behaviours), so if you don't use Service your Music could stop in any moment in the future.
PS: even Background Service could be killed from OS, but this case is very-very rare and only on Extreme Low Memory situations.
It will play as long as Android lets it live. It may stop at any moment, usually after 10-20 minutes.
Consider using Foreground Service to playback music. It will last until user kills it, and also provides notification bar with control over the playback.
I have noticed an issue with my audio streaming app on Android 6.0 devices. Audio streaming is done via HLS over a network connection. Audio playback occurs in a foreground service with an active notification. What I've noticed is that when the app enters doze mode/app standby, the wifi connection is lost and playback pauses. My service is in the foreground and has an active notification which, according to the docs, should qualify my app to not be interrupted. I also acquire and maintain a Wifi Lock. I've read about whitelisting my app, however apps like Spotify don't request any special permissions to avoid this issue. Any thoughts or suggestions?
The recommended solution is to have separate processes, one for audio playback and for the UI. See this long thread for lots of details
Here's the relevant section from Ms Hackborn:
... have your foreground service run in a different process than the activity. From what I can see, this will work fine. I would be interesting in seeing if you get the desired behavior there.
Also this is actually our recommended practice for this situation -- if you have a long-running foreground service, it should be in a separate process from the activity, so it doesn't force all of the memory associated with the activity to be kept around. (This is also why this bug got through, all of our [Google] apps use this pattern.)
I know that a process is an executing instance of an a program running in the foreground or background and that background processes run asynchronously(runs outside the main thread).
Would background music in your application be an example of a background process?(doesn't freeze up your UI in the main thread and it runs in its own thread)
Does process imply then that another program is running the music in the background?
I don't think that you need another process for playing music - you just need another thread. I don't think that you want to play music while your app is not in the foreground. For example if your app is a game which only produces sounds when it is active.
Obviously this is not true if your app is a media player which still plays music while in the background letting user interact with it using notifications which let the user play/pause, skip a song or stop playback.
Please see a question like this one: How to put media controller button on notification bar?
Your android application consist of process, services, threads, message queues. It application developer choice when to use what. As good developer, you should always try to make you application user experience smooth without and any hang. Always perform heavy/time consuming activity with service or async threads, and avoid such activity on main thread as it cause UI hangs.
I read Anndroid document - http://developer.android.com/guide/topics/media/mediaplayer.html
which said ".. you want it to continue playing while the user is interacting with other applications—then you must start a Service and control the MediaPlayer instance from there. "
But I found if I start a local a music file from an activity, then leave that activity, ( for example, press HOME key and interact with another app ), the music continues playing.
So, I don't understand " the "must start a Service" in document. Did I miss something?
This was not a big obstacle for my app at this moment. I am just wondering what's the potential problems could be if I do not use Service.( Services have longer lifespan, so the mediaplayer could be killed earlier, any others ? )
Our development is based on Android 2.2.
Thanks for any help in advance.
Big reason, if you are not using a service, users cannot listen to music outside of your app when the the activity gets paused or terminated. Technically you can make a music app but if your users cant listen to music when another app is in the foreground or the phone is in a different state(locked) it wont make for a very good app. You should take a look at the activity lifecycle for a deeper understanding of the process. Note that this behavior is by design for saving power, memory and cpu cycles.
It helps also not to think of services in the more traditional desktop dev usage. You want this thing to live even when your activity is not up and about.
For more about activity life cycles Managing the Activity Lifecycle
For the How
http://www.androidcompetencycenter.com/2009/01/basics-of-android-part-iii-android-services/
For the why
Why is it important to use Services for background tasks?
Playing the music in the Activity might be fine for now, but when Android is low on resources it might try to kill your Activity. When you add a service to an app, Android will try to keep that process alive as long as possible if it falls under certain criteria (such as playing music). Read over the Process Lifecycle section on Services:
http://developer.android.com/reference/android/app/Service.html#ProcessLifecycle
The activity can get killed by Android or by the user and then the music would stop playing.