Develop Reference

Android: Possible maximum number of audiosessions or effect engines for audio? (EQ, REV...)

for awhile now, I am working on a media playing app. In this app, I also programmed a little 5 Band EQ using mainly this code:
try
{
AppPreferencesClass ap = new AppPreferencesClass(ctx);
if (Activity_Player.eq != null)
{
Activity_Player.eq.Dispose();
}
Activity_Player.eq = new Android.Media.Audiofx.Equalizer(0, Activity_Player.mediaPlayerSessionId);
Activity_Player.eq.SetEnabled(true);
await Task.Run(() =>
{
if (Activity_Player.EqActive)
{
if (ap.getAwesomeSound())
{
Activity_Player.eq.SetBandLevel(0, Convert.ToInt16(Activity_Equalizer.awesomesound0));
Activity_Player.eq.SetBandLevel(1, Convert.ToInt16(Activity_Equalizer.awesomesound1));
Activity_Player.eq.SetBandLevel(2, Convert.ToInt16(Activity_Equalizer.awesomesound2));
Activity_Player.eq.SetBandLevel(3, Convert.ToInt16(Activity_Equalizer.awesomesound3));
Activity_Player.eq.SetBandLevel(4, Convert.ToInt16(Activity_Equalizer.awesomesound4));
}
else
{
Activity_Player.eq.SetBandLevel(0, Convert.ToInt16(ap.getEQ0()));
Activity_Player.eq.SetBandLevel(1, Convert.ToInt16(ap.getEQ1()));
Activity_Player.eq.SetBandLevel(2, Convert.ToInt16(ap.getEQ2()));
Activity_Player.eq.SetBandLevel(3, Convert.ToInt16(ap.getEQ3()));
Activity_Player.eq.SetBandLevel(4, Convert.ToInt16(ap.getEQ4()));
}
}
});
}
catch
{
}
For many days, this worked just fine but out of NO WHERE, the catch block sometimes gets activated. But only occasionally.On other times, try works fine but there are just no more changes to the audio being played. This is odd enough, since I never changed anything on this code after it starting working.
I then tried another phone (Samsung S4) on my code and the eq worked just perfectly.
So this got me googleing and I think I might have heard that there can only be as many audiosession IDs after you just would run out. I tested and the audio session ID used here is somewhere at 74,000.
So this could be an issue I thought but this would easialy be tested because I already had this very app running in the google play store just an older version of it. I am 100 percent positive, that in this version the EQ worked on my phone. Otherwise I would have not uploaded that version.
Anyway, I downloaded my old app from the play store and here we go:
It doesnt work anymore. The EQ in the old version also has simply NO effect on the audio. While ofcourse on my other phones this old version works perfectly.
Before I am going to reset my own personal phone I wanted to ask you guys if this could be infact the case.
Another thing is, that I am using many static variables in order to get the EQ to work right. Actually, the variable EQ itself is static. Do maybe static variables sort of leave a "trace" behind and maybe I have set the eq up just "too" many times? Although I am disposing of the object before intialising it again (see in my code).
Summing up:
1.) Can there maybe be a maxmium number of EQ or AudioSessionIDs and I have passed those?
2.) Can creating static variables over and over again in my code cause a memory leak so big, even deinstalling the app doesnt do anything?
Thank you!
This is the error log:
11-20 12:16:43.736 E/AudioEffect(16990): set(): AudioFlinger could not create effect, status: -38
11-20 12:16:43.736 E/AudioEffects-JNI(16990): Error setting AudioEffect
11-20 12:16:43.737 E/AudioEffect-JAVA(16990): Error code -19 when initializing AudioEffect.
Thread started: #311-20 12:16:43.745 V/MediaPlayerNative(16990): unrecognized message: (6, 0, 0)

After 2 days of googeling and trying evetything out, here is the issue:
NOT CALLING RELEASE() will have you eventually have to REBOOT your phone. It wont allow too many instances of an EQ to be set.
Solution:
if (eq != null)
{
eq.Release();
}

Viewing logcat in tablet

Is there a way to view the log on a tablet running 4.4? I've downloaded several apps like aLogCat and none of them show what my app writes out with S.o.p or Log.d. I have an intermittent bug that gives the Unfortunately appname has stopped message.Is there any way to view the log after this event without having to connect to a PC and use the adb program?
What other ways are there to get debug output? Would trapping the System.out and System.err classes get the stack trace?
Thanks,
Norm

You're focussing on tring to read out logcat, but there are better solutions for reading crash logs. My personal preference is Crashlytics, which automatically logs fatal exceptions and provides mechanisms for logging other messages.
The way all these crash reporters work, is by defining a UncaughtExceptionHandler:
Thread.setDefaultUncaughtExceptionHandler(
new MyUncaughtExceptionHandler(this));
If you prefer to use your own solution, you may want to look into using this. See this related question for more details.

Is there a way to view the log on a tablet running 4.4?
No, sorry. An app can only see its own log messages, not those from other apps. Hence, a third-party log viewer cannot see your app's messages.
Is there any way to view the log after this event without having to connect to a PC and use the adb program?
Use any standard crash management library, like ACRA, or services like Crashlytics, BugSense, etc.

The AIDE Application (Android Integrated Development Environment) allows one to develop android Apps directly on android device.
One particular feature is to read the logcat.
You can get it here https://play.google.com/store/apps/details?id=com.aide.ui

Here's the code I've put in the program. It seems to work:
// Define inner class to handle exceptions
class MyExceptionHandler implements Thread.UncaughtExceptionHandler {
public void uncaughtException(Thread t, Throwable e){
java.util.Date dt = new java.util.Date();
String fn = LogFilePathPfx + "exception_" + sdf.format(dt) + ".txt";
try{
PrintStream ps = new PrintStream( fn );
e.printStackTrace(ps);
ps.close();
System.out.println("wrote trace to " + fn);
e.printStackTrace(); // capture here also???
SaveStdOutput.stop(); // close here vs calling flush() in class
}catch(Exception x){
x.printStackTrace();
}
lastUEH.uncaughtException(t, e); // call last one Gives: "Unfortunately ... stopped" message
return; //???? what to do here
}
}
lastUEH = Thread.getDefaultUncaughtExceptionHandler(); // save previous one
Thread.setDefaultUncaughtExceptionHandler(new MyExceptionHandler());

How to programmatically answer a call in Android 4.0.3?

So as the subject states I need to be able to answer a phone call programmatically in Android 4.0.3 on an HTC OneX. I have read several places that the MODIFY_PHONE_STATE permission has been revoked by Google so to do this task you need a work around.
I have looked into two avenues so far:
(1) Following Guy's post here and using a BroadcastReceiver
(2) Using the following code to try and hit a key event through a shell command.
final Runtime r = Runtime.getRuntime();
try {
Process process = r.exec("input keyevent 5");
InputStream stream = process.getErrorStream();
log.v("Process Error Stream: " +stream.toString());
log.v("Sending shell command to Answer Call");
} catch (Exception e) {
log.v("Stack Trace: " + e.getStackTrace().toString());
e.printStackTrace();
}
I use this because keyevent 5 is KeyEvent.CALL according to Google and it works in adb using
adb shell input keyevent 5
My question is, what am I doing wrong? Because logically both of these methods makes sense but neither are working or even generating runtime errors of any kind.
Cheers

After days of research, I found that using both a broadcast receiver route and a runtime.exec() route it is simply not possible to answer a phone call in Android 4.0.3 using the Android API.
For those of you still wondering, I did find some useful information...You CAN answer a call through adb using the command adb shell input keyevent 5 5 is the key code for the call button and in Android it is the KEYEVENT_CALL

This works from Android 2.2 to 4.0 and now after adding the try catch to the last line it works for 4.1.2 and 4.2 Frankly speaking dont know how it works but it works for me.
Log.d(tag, "InSecond Method Ans Call");
// froyo and beyond trigger on buttonUp instead of buttonDown
Intent buttonUp = new Intent(Intent.ACTION_MEDIA_BUTTON);
buttonUp.putExtra(Intent.EXTRA_KEY_EVENT, new KeyEvent(
KeyEvent.ACTION_UP, KeyEvent.KEYCODE_HEADSETHOOK));
sendOrderedBroadcast(buttonUp, "android.permission.CALL_PRIVILEGED");
Intent headSetUnPluggedintent = new Intent(Intent.ACTION_HEADSET_PLUG);
headSetUnPluggedintent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
headSetUnPluggedintent.putExtra("state", 0);
headSetUnPluggedintent.putExtra("name", "Headset");
try {
sendOrderedBroadcast(headSetUnPluggedintent, null);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
This is working for me in Android 4.1.2 as well as i have tested on 4.2
This still gives an exception which is handled.

Here are several useful links, check them:
Answer automatically to Incoming Call
How to auto answer call programmatically
Auto answer

How to prevent name caching and detect bluetooth name changes on discovery

I'm writing an Android app which receives information from a Bluetooth device. Our client has suggested that the Bluetooth device (which they produce) will change its name depending on certain conditions - for the simplest example its name will sometimes be "xxx-ON" and sometimes "xxx-OFF". My app is just supposed to seek this BT transmitter (I use BluetoothAdapter.startDiscovery() ) and do different things depending on the name it finds. I am NOT pairing with the Bluetooth device (though I suppose it might be possible, the app is supposed to eventually work with multiple Android devices and multiple BT transmitters so I'm not sure it would be a good idea).
My code works fine to detect BT devices and find their names. Also, if the device goes off, I can detect the next time I seek, that it is not there. But it seems that if it is there and it changes name, I pick up the old name - presumably it is cached somewhere. Even if the bluetooth device goes off, and we notice that, the next time I detect it, I still see the old name.
I found this issue in Google Code: here but it was unclear to me even how to use the workaround given ("try to connect"). Has anyone done this and had any luck? Can you share code?
Is there a simple way to just delete the cached names and search again so I always find the newest names? Even a non-simple way would be good (I am writing for a rooted device).
Thanks

I would suggest 'fetchUuidsWithSdp()'. It's significance is that, unlike the similar getUuids() method, fetchUuidsWithSdp causes the device to update cached information about the remote device. And I believe this includes the remote name as well as the SPD.
Note that both the methods I mentioned are hidden prior to 4.0.3, so your code would look l ike this:
public static void startServiceDiscovery( BluetoothDevice device ) {
// Need to use reflection prior to API 15
Class cl = null;
try {
cl = Class.forName("android.bluetooth.BluetoothDevice");
} catch( ClassNotFoundException exc ) {
Log.e(CTAG, "android.bluetooth.BluetoothDevice not found." );
}
if (null != cl) {
Class[] param = {};
Method method = null;
try {
method = cl.getMethod("fetchUuidsWithSdp", param);
} catch( NoSuchMethodException exc ) {
Log.e(CTAG, "fetchUuidsWithSdp not found." );
}
if (null != method) {
Object[] args = {};
try {
method.invoke(device, args);
} catch (Exception exc) {
Log.e(CTAG, "Failed to invoke fetchUuidsWithSdp method." );
}
}
}
}
You'll then need to listen for the BluetoothDevice.ACTION_NAME_CHANGED intent, and extract BluetoothDevice.EXTRA_NAME from it.
Let me know if that helps.

How to programatically hide Caller ID on Android

on Android phones, under Call -> Additional settings -> Caller ID
it is possible to hide your caller ID. I want to do that programatically from my code, but was not able to find a way to do that.
I searched through
android.provider
android.telephony
for 2.1 release and was not able to find it.
Has anybody successfully solved this issue?
Thanks in advance. Best regards.

Here I will describe two approaches I tried.
1.) It is possible to display Additional Call Settings screen from your application. Although it looks like it is part of the Settings application, that is not true. This Activity is part of the Native Phone Application, and it may be approached with the following intent:
Intent additionalCallSettingsIntent = new Intent("android.intent.action.MAIN");
ComponentName distantActivity = new ComponentName("com.android.phone", "com.android.phone.GsmUmtsAdditionalCallOptions");
additionalCallSettingsIntent.setComponent(distantActivity);
startActivity(additionalCallSettingsIntent);
Then user has to manually press on the CallerID preference and gets radio button with 3 options.
This was not actually what I wanted to achieve when I asked this question. I wanted to avoid step where user has to select any further options.
2.) When approach described under 1.) is executed in the Native Phone Application, function setOutgoingCallerIdDisplay() from com.android.internal.telephony.Phone has been used.
This was the basis for the next approach: use Java Reflection on this class and try to invoke the function with appropriate parameters:
try
{
Class <?> phoneFactoryClass = Class.forName("com.android.internal.telephony.PhoneFactory");
try
{
Method getDefaultPhoneMethod = phoneFactoryClass.getDeclaredMethod("getDefaultPhone");
Method makeDefaultPhoneMethod = phoneFactoryClass.getMethod("makeDefaultPhone" , Context.class);
try
{
makeDefaultPhoneMethod.invoke(null, this);
Object defaultPhone = getDefaultPhoneMethod.invoke(null);
Class <?> phoneInterface = Class.forName("com.android.internal.telephony.Phone");
Method getPhoneServiceMethod = phoneInterface.getMethod("setOutgoingCallerIdDisplay", int.class, Message.class);
getPhoneServiceMethod.invoke(defaultPhone, 1, null);
}
catch (InvocationTargetException ex)
{
ex.printStackTrace();
}
catch (IllegalAccessException ex)
{
ex.printStackTrace();
}
}
catch (NoSuchMethodException ex)
{
ex.printStackTrace();
}
}
catch (ClassNotFoundException ex)
{
ex.printStackTrace();
}
Firstly I tried just to use getDefaultPhone(), but I get RuntimeException
"PhoneFactory.getDefaultPhone must be called from Looper thread"
Obviously, issue lies in the fact that I tried to call this method from the Message Loop that was not the Native Phone App one.
Tried to avoid this by making own default phone, but this was a security violation:
ERROR/AndroidRuntime(2338): java.lang.SecurityException: Permission Denial: not allowed to send broadcast android.provider.Telephony.SPN_STRINGS_UPDATED from pid=2338, uid=10048
The only way to overcome (both of) this would be to sign your app with the same key as the core systems app, as described under
Run secure API calls as root, android

I'm not sure if this is a global feature, but Australian phones can hide their number by prefixing the caller's number with #31# or 1831. This may not be the perfect solution, but a prefix like this could possibly work for your requirements during coding.