Develop Reference

How to prevent phone from going to idle mode

I've developed an application that streams music (via internet connection) using service and having trubles streaming content without phone going idle.
While i was developing my application each time i tried case mentioned below the music was reproducing fine.
Use case : search song, select song from results, play song, screen off -> auto play next song from result list
I'm developing using real device - Huawei Mate 20 Lite - OS v8.01 so while debugging it gotta use USB cabel.
Like i said following the use case above while hooked on USB the auto play while screen off works good. The case it doesn't work good is when the cable is not connected (only mobile data turned on).
What I've figured out is that phone when connected on USB is probably keeping the device awake and it doesn't go to idle mode while when not connected after around 5mins the device probably shuts down processes that cost energy or it shuts down connection to mobile data i'm not sure and there's where i need you guys.
Also I've tested app using HTC U Play - OS v6.0 and the streaming goes smooth without interrupts while screen off and phone wasn't touched for 10+mins.
Also I've tried to acquire wakelock inside oncreate and without releasing it just to see if it helps and it doesn't.
pm = (PowerManager) getApplicationContext().getSystemService(Context.POWER_SERVICE);
wl = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "MyWakeLock");
wl.acquire();

This problem you are facing can be due to the fact that after Andriod 6.0, all apps are getting optimized for optimizing the battery usage.
If you really think, the reason behind the application to go killed is inactivity. Then, probably, its because of battery optimization software itself.
You can enable another permission while installing the app on the device where you can update the list of unoptimized app by adding an entry for your app.
Originally, you will be able to do the manual settings by following below instruction.
. Head for the ‘Settings‘ app and then ‘Battery‘
. On the ‘three dots‘ menu, top right, you’ll find ‘Battery optimisation‘.
. Here you’ll see a list of all applications which shouldn’t be ‘optimised‘ (for which read ‘can be handled by Doze and App Standby’) – by default the list is usually very small, with almost all apps enabled for ‘optimisation’. Which is fine for general users, but if, like me, you want a few applications to live outside of the new battery optimisations, then tap on the ‘Not optimised‘ pick list and choose ‘All apps‘
. As you’d expect, every application on your phone is listed (this may be quite long) – swipe down until you find the application(s) that you particularly want to always keep running. Tap on the application name
. From the two choices, check the box for ‘Don’t optimise‘.

How to enable android bluetooth a2dp sink and play music on android L

we recently work on a audio box which based on Android, as a audio box must act to a reciver with bluetooth(while a2dp sink profile in bluetooth can do this), but we have do many works over weeks on it , but it still not work, so i'd like to ask somebody who know or had similar expirence on it could help.
our works :
1、packages/apps/Bluetooth/res/values/config.xml
<bool name="profile_supported_a2dp_sink">true</bool>
<bool name="profile_supported_hfpclient">true</bool>
2、external/bluetooth/bluedroid/include/bt_target.h
#define BTA_AV_SINK_INCLUDED TRUE
after these bluetooth seems to worked , i can user a phone link to these box and i can play music with a player through bluetooth , and also i can see the data packages in the box by tcpdump, but there is no sound , we also find some other informations :
Android device as a receiver for A2DP profile
but it seems didn't work.
so anybody could help.
thanks a lot

MPVolumeView equivalent for Android

Does anyone know if there is an equivalent to MPVolumeView available in Android?
Basically, it's a a built in component in iOS that can present users with a system volume slider, and / or (what I'm really after in Android) a list of available bluetooth / Airplay audio output options (i.e. bluetooth speakers). The image below shows it in action:
Is there any easy option for listing bluetooth etc. audio routing options in Android, or do you have to write all the scanning, connecting, audio routing code yourself?

From the lack of response, and the endless googling around the subject of connecting to A2DP Bluetooth sinks, that I've been doing lately, the sad answer to this question seems to be no, there is nothing quite like the MPVolumeView in Android.
The nearest thing would be to either write it all yourself, as I feared, or, to simply pop open the system Bluetooth options windows from your app (ensuring you've got BLUETOOTH_ADMIN permissions set up in your manifest first):
Intent intentOpenBluetoothSettings = new Intent();
intentOpenBluetoothSettings.setAction(android.provider.Settings.ACTION_BLUETOOTH_SETTINGS);
startActivity(intentOpenBluetoothSettings);

Route audio to bluetooth A2DP device while ringing [Android]

I am trying to identify how to route a very short audio stream (a notification) to a bluetooth headphone that is already paired with the device, while the device is ringing.
When I play any audio at any time, it is routed to the bluetooth device, no problem.
But if I try to start playing the audio when receiving an android.intent.action.PHONE_STATE, in RINGING state, the audio is not routed as expected.
I can see that the AudioManager's setBluetoothA2dpOn method has became deprecated, but I actually tried it but is seems has no effect.
I have tried the MediaRouter object, but I can see that MediaRouter.getSelectedRoute(MediaRouter.ROUTE_TYPE_LIVE_AUDIO) points to the RouteInfo of the Bluetooth device while the device is ringing, and the AudioManager.isBluetoothA2dpOn is true.
So, can any one tell me why the audio route is like this in the ringing moment? is there any way to force the audio to be routed to the Bluetooth device in such case?
[UPDATED]
I have tried again today and I have discovered something that may be the cause of the problem.
I have created a BroadcaseReceiver to detect the change in the android.intent.action.PHONE_STATE. if an intent is received and the state is currently ringing, check for AudioManager's mode and you will find it is MODE_NORMAL. but few seconds later the phone will start actually ringing and the mode is going to be changed into MODE_RINGTONE. trying to manually set the mode using the method setMode(AudioManager.MODE_NORMAL) is useless then, the state remains MODE_RINGTONE even after setting it to MODE_NORMAL.
Now, I think the cause of the problem is that in the MODE_RINGTONE mode, all the streams are directed to the phone speaker and here there is no way offered by the android system to change the mode.

I think the Media player realease the bluetooth connection when the phone is ringing. You can try to obtain the bluetooth audio connection and see if Media player now play through your obtained connection. You can use my class at my answer Using the Android RecognizerIntent with a bluetooth headset and see if it works. The audio in the class is Sco only.

As stated in the JavaDoc for the StartBluetoothSco method:
Note that the phone application always has the priority on the usage of the SCO connection for telephony. If this method is called while the phone is in call it will be ignored. Similarly, if a call is received or sent while an application is using the SCO connection, the connection will be lost for the application and NOT returned automatically when the call ends.`
I tried to start sco then play a music clip in normal mode, it played to the Bluetooth headset without problems, although I couldnot stop the microphone that caused the input stream plays to the headset. I then tried to call my target phone from another phone while the music is still playing, I found that the stream has got redirected automatically to the phone speaker. After the ringing mode is finished, the stream did not get redirected again to the Bluetooth headset and I think that behavior is normal according to what is stated in the JavaDoc above.
My guessing is that Android tries to protect the ringing and in-call modes as possible in order not to allow any unwanted interference from applications. In other words, when in ringing mode then no sound is going to be played to the headset until the call is accepted, and you cannot even change the AudioManager mode from ringing to another mode, your call for mode setter will be ignored.

I have tried the AudioTrack instead of MediaPlayer, but that makes no difference.
I have then tried the TextToSpeech engine like this:
in the main activity, initialize on create:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textToSpeech=new TextToSpeech(this, this);
textToSpeech.setLanguage(Locale.US);
textToSpeech.addEarcon("[wwww]", "XXXXXXXXXXXXXXXXXXXXXXX", R.raw.a);
}
in the broadcast receiver class when rining starting the Bluetooth utility class and adding the below to the onScoAudioConnected method
textToSpeech.playEarcon("[wwww]", TextToSpeech.QUEUE_FLUSH, null);
This did not work too.

How to capture or reroute navigation voice stream

There is a problem when using Google Navigation on Android with a Bluetooth device. Navigation sends the audio for the turn-by-turn instructions over the A2DP stream. I have a Motorola T605 Bluetooth car kit and it supports HFP and A2DP. I often just listen to the old fashioned car radio though. In this scenario I never hear turn-by-turn directions because my live A2DP stream is being sent to the radio AUX input but I am listening to the radio instead. My app has a feature where it reads out SMS messages to me. I have it set up so you can pick the stream you want to use for this. I prefer using AudioManager.STREAM_VOICE_CALL since it uses a dedicated separate speaker on the T605.
I have looked into a few ways to handle this:
1) Reroute notifications to Bluetooth SCO instead of A2DP. I have not fund a way to do this. I am able to send TTS messages I create over this path and it works great (I have an SMS reader built into my app). I tried activating SCO but the turn-by-turn instructions stream moves to the phone internal speaker instead of the voice call stream like I would prefer.
2) Capture the navigation messages and echo them back over the SCO path. I can't find a way to intercept or capture the navigation stream though. Does Google Navigation use the TTS engine or its own methods to create the voice output? It would be great to just get the directions in a text string since I could easily send that to the TTS engine and route it where I want like I do with SMS strings.
You can see my app source here: http://code.google.com/p/a2dpvolume/
Any thoughts?

Unfortunately I think you're SOOL when it comes to rerouting the navigation messages to BT SCO. I would expect the navigation app to use either the TTS or NOTIFICATION stream type to play the messages, and both of those stream types follow the MEDIA routing strategy (for NOTIFICATIONs that is at least typically true when there's no active voice call).
Although the behavior is up to each vendor to decide, my guess is that you'll find that in most implementations streams that follow the MEDIA routing strategy won't ever be routed to BT SCO, except during an ongoing voice call that is routed to BT SCO.
The best you could do in terms of routing is to force the routing to the loudspeaker, or to "anything but A2DP" (which means wired headset if one is attached, or the loudspeaker otherwise).
Here's how you could do that (I haven't verified that this works on every phone out there):
Class audioSystemClass = Class.forName("android.media.AudioSystem");
Method setForceUse = audioSystemClass.getMethod("setForceUse",
int.class,
int.class);
// 1 == FOR_MEDIA, 10 == FORCE_NO_BT_A2DP (FORCE_SPEAKER would be 1).
setForceUse.invoke(null, 1, 10);