[RK3288][Android6.0] 调试笔记 --- Audio分离DTMF tone引起的异常

Platform: Rockchip
OS: Android 6.0
Kernel: 3.10.92

由于Audio原始设计DTMF stream最终转换成MUSIC stream, 现在想把DTMF独立出来单独使用，因此修改
STREAM_VOLUME_ALIAS_DEFAULT数组

    private final int[] STREAM_VOLUME_ALIAS_DEFAULT = new int[] {        AudioSystem.STREAM_VOICE_CALL,      // STREAM_VOICE_CALL        AudioSystem.STREAM_RING,            // STREAM_SYSTEM        AudioSystem.STREAM_RING,            // STREAM_RING        AudioSystem.STREAM_MUSIC,           // STREAM_MUSIC        AudioSystem.STREAM_ALARM,           // STREAM_ALARM        AudioSystem.STREAM_RING,            // STREAM_NOTIFICATION        AudioSystem.STREAM_BLUETOOTH_SCO,   // STREAM_BLUETOOTH_SCO        AudioSystem.STREAM_RING,            // STREAM_SYSTEM_ENFORCED        //把AudioSystem.STREAM_MUSIC替换成AudioSystem.STREAM_DTMF        AudioSystem.STREAM_DTMF,            // STREAM_DTMF        AudioSystem.STREAM_MUSIC            // STREAM_TTS    };

private void updateStreamVolumeAlias(boolean updateVolumes, String caller) {    int dtmfStreamAlias;    switch (mPlatformType) {    case AudioSystem.PLATFORM_VOICE:        mStreamVolumeAlias = STREAM_VOLUME_ALIAS_VOICE;        dtmfStreamAlias = AudioSystem.STREAM_RING;        break;    case AudioSystem.PLATFORM_TELEVISION:        mStreamVolumeAlias = STREAM_VOLUME_ALIAS_TELEVISION;        dtmfStreamAlias = AudioSystem.STREAM_MUSIC;        break;    default:        mStreamVolumeAlias = STREAM_VOLUME_ALIAS_DEFAULT;        dtmfStreamAlias = AudioSystem.STREAM_MUSIC;    }    //不管是什么平台，都设置成AudioSystem.STREAM_DTMF    dtmfStreamAlias = AudioSystem.STREAM_DTMF;    ......｝

修改开机后发生了exception:

01-03 15:34:39.982   553   553 W SystemServer: ***********************************************01-03 15:34:39.983   553   553 E SystemServer: BOOT FAILURE starting Audio Service01-03 15:34:39.983   553   553 E SystemServer: java.lang.ArrayIndexOutOfBoundsException: length=7; index=801-03 15:34:39.983   553   553 E SystemServer:  at com.android.server.audio.AudioService.createStreamStates(AudioService.java:903)01-03 15:34:39.983   553   553 E SystemServer:  at com.android.server.audio.AudioService.<init>(AudioService.java:639)01-03 15:34:39.983   553   553 E SystemServer:  at com.android.server.SystemServer.startOtherServices(SystemServer.java:874)01-03 15:34:39.983   553   553 E SystemServer:  at com.android.server.SystemServer.run(SystemServer.java:279)01-03 15:34:39.983   553   553 E SystemServer:  at com.android.server.SystemServer.main(SystemServer.java:171)01-03 15:34:39.983   553   553 E SystemServer:  at java.lang.reflect.Method.invoke(Native Method)01-03 15:34:39.983   553   553 E SystemServer:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:772)01-03 15:34:39.983   553   553 E SystemServer:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:662)

是createStreamStates()引起：

private void createStreamStates() {    int numStreamTypes = AudioSystem.getNumStreamTypes();    VolumeStreamState[] streams = mStreamStates = new VolumeStreamState[numStreamTypes];    for (int i = 0; i < numStreamTypes; i++) {        //这行数组越界        streams[i] = new VolumeStreamState(System.VOLUME_SETTINGS[mStreamVolumeAlias[i]], i);    }}

VOLUME_SETTINGS：

/** * The mapping of stream type (integer) to its setting. * * @removed  Not used by anything since API 2. */public static final String[] VOLUME_SETTINGS = {    VOLUME_VOICE, VOLUME_SYSTEM, VOLUME_RING, VOLUME_MUSIC,    VOLUME_ALARM, VOLUME_NOTIFICATION, VOLUME_BLUETOOTH_SCO};

而AudioSystem.STREAM_DTMF对应的值是8， 越界了。
看注释，此数组已经被弃用了，估计不维护了，但是在createStreamStates()却引用了这个字符串数组，导致异常产生。

解决方法：

private void createStreamStates() {    int numStreamTypes = AudioSystem.getNumStreamTypes();    VolumeStreamState[] streams = mStreamStates = new VolumeStreamState[numStreamTypes];    for (int i = 0; i < numStreamTypes; i++) {       //判断如果是DTMF，就另外赋值       if (i == 8)          streams[i] = new VolumeStreamState("volume_dtmf", i);       else             streams[i] = new VolumeStreamState(System.VOLUME_SETTINGS[mStreamVolumeAlias[i]], i);        }        checkAllFixedVolumeDevices();        checkAllAliasStreamVolumes();        checkMuteAffectedStreams();     }}