uninitialized AudioTrack exception when I try to generate tone on 22nd time

Question

I have a requirement that I need to display a dial pad like screen and I have to generate 1khz tone (not DTMF tone) whenever user presses on a dial pad buttons.

I have used the code from the below link to generate 1 khz tone:

Playing an arbitrary tone with Android

When I started dialing buttons on my dialpad screen till 21 presses it is successfully generating tone but after 22nd attempt I am getting Application Not Responding (ANR) error and I need to close the app.

Below is my code:

 final float duration = 0.3f; // seconds
final int sampleRate = 4000;
final int numSamples = (int)duration * sampleRate + 100;
final double sample[] = new double[numSamples];
final double freqOfTone = 1000; // hz
final byte generatedSnd[] = new byte[2 * numSamples];

final Handler handler = new Handler();


      public void onClick(View v) {
    // TODO Auto-generated method stub

    int id = v.getId();

    playSound();
    }


   private void playSound()
{

    final Thread thread = new Thread(new Runnable() {
        public void run() {
            genTone();
            handler.post(new Runnable() {

                public void run() {
                    playSound1();
                }
            });
        }
    });
    thread.start();


}

 void playSound1(){
     final AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
             sampleRate, AudioFormat.CHANNEL_CONFIGURATION_MONO,
             AudioFormat.ENCODING_PCM_16BIT, numSamples,
             AudioTrack.MODE_STATIC);
         audioTrack.write(generatedSnd, 0, generatedSnd.length);


         audioTrack.play();
 }

void genTone(){
    // fill out the array
    for (int i = 0; i < numSamples; ++i) {
        sample[i] = Math.sin(2 * Math.PI * i / (sampleRate/freqOfTone));
    }

    // convert to 16 bit pcm sound array
    // assumes the sample buffer is normalised.
    int idx = 0;
    for (final double dVal : sample) {
        // scale to maximum amplitude
        final short val = (short) ((dVal * 32767));
        // in 16 bit wav PCM, first byte is the low order byte
        generatedSnd[idx++] = (byte) (val & 0x00ff);
        generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);

    }
}

onClick() method will be called each time when I press buttons on the dialpad.

with the above code I am getting this output in Logcat:

05.500 E/AudioFlinger(   85): no more track names available

09-21 05:20:05.500 E/AudioTrack(  133): AudioFlinger could not create track, status: -12

09-21 05:20:05.503 E/SoundPool(  133): Error creating AudioTrack

09-21 05:20:05.535 E/AudioFlinger(   85): no more track names available

09-21 05:20:05.535 E/AudioTrack( 6080): AudioFlinger could not create track, status: -12

09-21 05:20:05.535 E/AudioTrack-JNI( 6080): Error initializing AudioTrack

09-21 05:20:05.535 E/AudioTrack-Java( 6080): [ android.media.AudioTrack ] Error code -20 when initializing AudioTrack.

09-21 05:20:05.535 D/AndroidRuntime( 6080): Shutting down VM

09-21 05:20:05.535 W/dalvikvm( 6080): threadid=1: thread exiting with uncaught exception (group=0x40015578)

09-21 05:20:05.539 E/AndroidRuntime( 6080): FATAL EXCEPTION: main

09-21 05:20:05.539 E/AndroidRuntime( 6080): java.lang.IllegalStateException: play() called on uninitialized AudioTrack.

09-21 05:20:05.539 E/AndroidRuntime( 6080):     at android.media.AudioTrack.play(AudioTrack.java:824)

09-21 05:20:05.539 E/AndroidRuntime( 6080):     at com.android.dial.DialPadScreen.playSound1(DialPadScreen.java:274)

09-21 05:20:05.539 E/AndroidRuntime( 6080):     at com.android.dial.DialPadScreen$1$1.run(DialPadScreen.java:248)

09-21 05:20:05.539 E/AndroidRuntime( 6080):     at android.os.Handler.handleCallback(Handler.java:587)

09-21 05:20:05.539 E/AndroidRuntime( 6080):     at android.os.Handler.dispatchMessage(Handler.java:92)

09-21 05:20:05.539 E/AndroidRuntime( 6080):     at android.os.Looper.loop(Looper.java:123)

09-21 05:20:05.539 E/AndroidRuntime( 6080):     at android.app.ActivityThread.main(ActivityThread.java:3687)

09-21 05:20:05.539 E/AndroidRuntime( 6080):     at java.lang.reflect.Method.invokeNative(Native Method)

09-21 05:20:05.539 E/AndroidRuntime( 6080):     at java.lang.reflect.Method.invoke(Method.java:507)

09-21 05:20:05.539 E/AndroidRuntime( 6080):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)

09-21 05:20:05.539 E/AndroidRuntime( 6080):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)

09-21 05:20:05.539 E/AndroidRuntime( 6080):     at dalvik.system.NativeStart.main(Native Method)

09-21 05:20:05.542 E/        (  133): Dumpstate > /data/log/dumpstate_app_error

09-21 05:20:05.542 W/ActivityManager(  133):   Force finishing activity com.android.dial/.DialPadScreen

I am printing the state of the "audioTrack" till 21th time I am getting value 1 (STATE_INITIALIZED) after that I am getting value '0' (STATE_UNINITIALIZED). Dont know why state is getting changed.

Please help me what are the changes I need to do prevent this froce close issue in my app. or Please suggest if there's any alternative to do this.

Answer 1

About the number of 21 successfully generated tones and next fails, I think you have to free the previously created instances invoking audioTrack.release() method.

In order to avoid the IllegalStateException:
After created an instance of AudioTrack you have to test if it is well initialized.
Using MODE_STATIC mode, if it does not correctly initialize, the state will be: STATE_UNINITIALIZED, instead, if correctly initialized: STATE_NO_STATIC_DATA, when you invoke write method the state will be changed to STATE_INITIALIZED.
Using MODE_STREAM mode, if it does not correctly initialize, the state will be: STATE_UNINITIALIZED, instead, if correctly initialized: STATE_INITIALIZED.
Reading on source of AudioTrack I seen that. I think this is very strange because the object returned by constructor is not usable because it is not possible to initialize after construction.