1.需求:Android 系统出厂默认的音量值过小,需要把音量默认初始值改成音量的最大值.
2.涉及核心代码:
frameworks/base/media/java/android/media/AudioSystem.java
frameworks/base/services/core/java/com/android/server/audio/AudioService.java3.系统音量默认初始值在AudioSystem.java中定义,代码如下:
/** @hide */
public static int[] DEFAULT_STREAM_VOLUME = new int[] {
4, // STREAM_VOICE_CALL
7, // STREAM_SYSTEM
5, // STREAM_RING
5, // STREAM_MUSIC
6, // STREAM_ALARM
5, // STREAM_NOTIFICATION
7, // STREAM_BLUETOOTH_SCO
7, // STREAM_SYSTEM_ENFORCED
5, // STREAM_DTMF
5, // STREAM_TTS
5, // STREAM_ACCESSIBILITY
5, // STREAM_ASSISTANT
};3.系统音量最大值和最小值定义在AudioService.java 中,代码如下:
/** Maximum volume index values for audio streams */
protected static int[] MAX_STREAM_VOLUME = new int[] {
5, // STREAM_VOICE_CALL
7, // STREAM_SYSTEM
7, // STREAM_RING
15, // STREAM_MUSIC
7, // STREAM_ALARM
7, // STREAM_NOTIFICATION
15, // STREAM_BLUETOOTH_SCO
7, // STREAM_SYSTEM_ENFORCED
15, // STREAM_DTMF
15, // STREAM_TTS
15, // STREAM_ACCESSIBILITY
15 // STREAM_ASSISTANT
};
/** Minimum volume index values for audio streams */
protected static int[] MIN_STREAM_VOLUME = new int[] {
1, // STREAM_VOICE_CALL
0, // STREAM_SYSTEM
0, // STREAM_RING
0, // STREAM_MUSIC
1, // STREAM_ALARM
0, // STREAM_NOTIFICATION
0, // STREAM_BLUETOOTH_SCO
0, // STREAM_SYSTEM_ENFORCED
0, // STREAM_DTMF
0, // STREAM_TTS
1, // STREAM_ACCESSIBILITY
0 // STREAM_ASSISTANT
};------------------------------------------------------------修改方案一---------------------------------------------
在AudioSystem.Java中,修改把默认的音量值改成需要的值,如:把设置里音量中的"媒体音量","通话音量","铃声和通知音量","闹钟音量" 改成最大值.
(1)第一步:对照AudioService.java中的MAX_STREAM_VOLUME数组中的值做相应的修改.
/** @hide */
public static int[] DEFAULT_STREAM_VOLUME = new int[] {
5, // STREAM_VOICE_CALL
7, // STREAM_SYSTEM
7, // STREAM_RING
15, // STREAM_MUSIC
7, // STREAM_ALARM
7, // STREAM_NOTIFICATION
15, // STREAM_BLUETOOTH_SCO
7, // STREAM_SYSTEM_ENFORCED
15, // STREAM_DTMF
15, // STREAM_TTS
15, // STREAM_ACCESSIBILITY
15, // STREAM_ASSISTANT
};
(2)步骤二:由于AudioService.java在构造函数中,会覆盖最大值和默认初始值,所以需要把构造函数中从配置文件中取值的代码注释掉,才能让步骤一中修改的数组的值起作用,最后清楚系统数据后便会生效.
/** @hide */
public AudioService(Context context) {
this(context, AudioSystemAdapter.getDefaultAdapter(),
SystemServerAdapter.getDefaultAdapter(context));
}
public AudioService(Context context, AudioSystemAdapter audioSystem,
SystemServerAdapter systemServer) {
sLifecycleLogger.log(new AudioEventLogger.StringEvent("AudioService()"));
mContext = context;
mContentResolver = context.getContentResolver();
mAppOps = (AppOpsManager)context.getSystemService(Context.APP_OPS_SERVICE);
mAudioSystem = audioSystem;
mSystemServer = systemServer;
mPlatformType = AudioSystem.getPlatformType(context);
mIsSingleVolume = AudioSystem.isSingleVolume(context);
mUserManagerInternal = LocalServices.getService(UserManagerInternal.class);
mActivityManagerInternal = LocalServices.getService(ActivityManagerInternal.class);
mSensorPrivacyManagerInternal =
LocalServices.getService(SensorPrivacyManagerInternal.class);
PowerManager pm = (PowerManager)context.getSystemService(Context.POWER_SERVICE);
mAudioEventWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "handleAudioEvent");
mSfxHelper = new SoundEffectsHelper(mContext);
mVibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
mHasVibrator = mVibrator == null ? false : mVibrator.hasVibrator();
mSupportsMicPrivacyToggle = context.getSystemService(SensorPrivacyManager.class)
.supportsSensorToggle(SensorPrivacyManager.Sensors.MICROPHONE);
mUseVolumeGroupAliases = mContext.getResources().getBoolean(
com.android.internal.R.bool.config_handleVolumeAliasesUsingVolumeGroups);
// Initialize volume
// Priority 1 - Android Property
// Priority 2 - Audio Policy Service
// Priority 3 - Default Value
if (AudioProductStrategy.getAudioProductStrategies().size() > 0) {
int numStreamTypes = AudioSystem.getNumStreamTypes();
for (int streamType = numStreamTypes - 1; streamType >= 0; streamType--) {
AudioAttributes attr =
AudioProductStrategy.getAudioAttributesForStrategyWithLegacyStreamType(
streamType);
int maxVolume = AudioSystem.getMaxVolumeIndexForAttributes(attr);
if (maxVolume != -1) {
MAX_STREAM_VOLUME[streamType] = maxVolume;
}
int minVolume = AudioSystem.getMinVolumeIndexForAttributes(attr);
if (minVolume != -1) {
MIN_STREAM_VOLUME[streamType] = minVolume;
}
}
if (mUseVolumeGroupAliases) {
// Set all default to uninitialized.
for (int stream = 0; stream < AudioSystem.DEFAULT_STREAM_VOLUME.length; stream++) {
AudioSystem.DEFAULT_STREAM_VOLUME[stream] = UNSET_INDEX;
}
}
}
/*注释开始
int maxCallVolume = SystemProperties.getInt("ro.config.vc_call_vol_steps", -1);
if (maxCallVolume != -1) {
MAX_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] = maxCallVolume;
}
int defaultCallVolume = SystemProperties.getInt("ro.config.vc_call_vol_default", -1);
if (defaultCallVolume != -1 &&
defaultCallVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] &&
defaultCallVolume >= MIN_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL]) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] = defaultCallVolume;
} else {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] =
(MAX_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] * 3) / 4;
}
int maxMusicVolume = SystemProperties.getInt("ro.config.media_vol_steps", -1);
if (maxMusicVolume != -1) {
MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] = maxMusicVolume;
}
int defaultMusicVolume = SystemProperties.getInt("ro.config.media_vol_default", -1);
if (defaultMusicVolume != -1 &&
defaultMusicVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] &&
defaultMusicVolume >= MIN_STREAM_VOLUME[AudioSystem.STREAM_MUSIC]) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] = defaultMusicVolume;
} else {
if (isPlatformTelevision()) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] =
MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] / 4;
} else {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] =
MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] / 3;
}
}
int maxAlarmVolume = SystemProperties.getInt("ro.config.alarm_vol_steps", -1);
if (maxAlarmVolume != -1) {
MAX_STREAM_VOLUME[AudioSystem.STREAM_ALARM] = maxAlarmVolume;
}
int defaultAlarmVolume = SystemProperties.getInt("ro.config.alarm_vol_default", -1);
if (defaultAlarmVolume != -1 &&
defaultAlarmVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_ALARM]) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_ALARM] = defaultAlarmVolume;
} else {
// Default is 6 out of 7 (default maximum), so scale accordingly.
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_ALARM] =
6 * MAX_STREAM_VOLUME[AudioSystem.STREAM_ALARM] / 7;
}
int maxSystemVolume = SystemProperties.getInt("ro.config.system_vol_steps", -1);
if (maxSystemVolume != -1) {
MAX_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM] = maxSystemVolume;
}
int defaultSystemVolume = SystemProperties.getInt("ro.config.system_vol_default", -1);
if (defaultSystemVolume != -1 &&
defaultSystemVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM]) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM] = defaultSystemVolume;
} else {
// Default is to use maximum.
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM] =
MAX_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM];
}
注释结束*/
createAudioSystemThread();
AudioSystem.setErrorCallback(mAudioSystemCallback);
updateAudioHalPids();
boolean cameraSoundForced = readCameraSoundForced();
mCameraSoundForced = new Boolean(cameraSoundForced);
sendMsg(mAudioHandler,
MSG_SET_FORCE_USE,
SENDMSG_QUEUE,
AudioSystem.FOR_SYSTEM,
cameraSoundForced ?
AudioSystem.FORCE_SYSTEM_ENFORCED : AudioSystem.FORCE_NONE,
new String("AudioService ctor"),
0);
mSafeMediaVolumeState = Settings.Global.getInt(mContentResolver,
Settings.Global.AUDIO_SAFE_VOLUME_STATE,
SAFE_MEDIA_VOLUME_NOT_CONFIGURED);
// The default safe volume index read here will be replaced by the actual value when
// the mcc is read by onConfigureSafeVolume()
mSafeMediaVolumeIndex = mContext.getResources().getInteger(
com.android.internal.R.integer.config_safe_media_volume_index) * 10;
mUseFixedVolume = mContext.getResources().getBoolean(
com.android.internal.R.bool.config_useFixedVolume);
mDeviceBroker = new AudioDeviceBroker(mContext, this);
mRecordMonitor = new RecordingActivityMonitor(mContext);
mRecordMonitor.registerRecordingCallback(mVoiceRecordingActivityMonitor, true);
// must be called before readPersistedSettings() which needs a valid mStreamVolumeAlias[]
// array initialized by updateStreamVolumeAlias()
updateStreamVolumeAlias(false /*updateVolumes*/, TAG);
readPersistedSettings();
readUserRestrictions();
mPlaybackMonitor =
new PlaybackActivityMonitor(context, MAX_STREAM_VOLUME[AudioSystem.STREAM_ALARM]);
mPlaybackMonitor.registerPlaybackCallback(mVoicePlaybackActivityMonitor, true);
mMediaFocusControl = new MediaFocusControl(mContext, mPlaybackMonitor);
readAndSetLowRamDevice();
mIsCallScreeningModeSupported = AudioSystem.isCallScreeningModeSupported();
if (mSystemServer.isPrivileged()) {
LocalServices.addService(AudioManagerInternal.class, new AudioServiceInternal());
mUserManagerInternal.addUserRestrictionsListener(mUserRestrictionsListener);
mRecordMonitor.initMonitor();
}
mMonitorRotation = SystemProperties.getBoolean("ro.audio.monitorRotation", false);
// done with service initialization, continue additional work in our Handler thread
queueMsgUnderWakeLock(mAudioHandler, MSG_INIT_STREAMS_VOLUMES,
0 /* arg1 */, 0 /* arg2 */, null /* obj */, 0 /* delay */);
}--------------------------------------修改方案二---------------------------------------------
由于AudioService.java构造函数中会从配置文件中对音量默认值和音量最大值再次赋值,
int maxCallVolume = SystemProperties.getInt("ro.config.vc_call_vol_steps", -1);
if (maxCallVolume != -1) {
MAX_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] = maxCallVolume;
}
//从系统属性"ro.config.vc_call_vol_default"中获取默认电话音量
int defaultCallVolume = SystemProperties.getInt("ro.config.vc_call_vol_default", -1);
if (defaultCallVolume != -1 &&
defaultCallVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] &&
defaultCallVolume >= MIN_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL]) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] = defaultCallVolume;
} else {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] =
(MAX_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] * 3) / 4;
}
int maxMusicVolume = SystemProperties.getInt("ro.config.media_vol_steps", -1);
if (maxMusicVolume != -1) {
MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] = maxMusicVolume;
}
//从系统属性"ro.config.media_vol_default"中获取默认媒体音量
int defaultMusicVolume = SystemProperties.getInt("ro.config.media_vol_default", -1);
if (defaultMusicVolume != -1 &&
defaultMusicVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] &&
defaultMusicVolume >= MIN_STREAM_VOLUME[AudioSystem.STREAM_MUSIC]) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] = defaultMusicVolume;
} else {
if (isPlatformTelevision()) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] =
MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] / 4;
} else {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] =
MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] / 3;
}
}
int maxAlarmVolume = SystemProperties.getInt("ro.config.alarm_vol_steps", -1);
if (maxAlarmVolume != -1) {
MAX_STREAM_VOLUME[AudioSystem.STREAM_ALARM] = maxAlarmVolume;
}
//从系统属性"ro.config.alarm_vol_default"中获取默认闹钟和通知音量
int defaultAlarmVolume = SystemProperties.getInt("ro.config.alarm_vol_default", -1);
if (defaultAlarmVolume != -1 &&
defaultAlarmVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_ALARM]) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_ALARM] = defaultAlarmVolume;
} else {
// Default is 6 out of 7 (default maximum), so scale accordingly.
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_ALARM] =
6 * MAX_STREAM_VOLUME[AudioSystem.STREAM_ALARM] / 7;
}
int maxSystemVolume = SystemProperties.getInt("ro.config.system_vol_steps", -1);
if (maxSystemVolume != -1) {
MAX_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM] = maxSystemVolume;
}
//从系统属性"ro.config.system_vol_default"中获取默认系统音量
int defaultSystemVolume = SystemProperties.getInt("ro.config.system_vol_default", -1);
if (defaultSystemVolume != -1 &&
defaultSystemVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM]) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM] = defaultSystemVolume;
} else {
// Default is to use maximum.
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM] =
MAX_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM];
}所以可以在配置文件中添加对应的属性,并赋值,这样就不需要修改代码.默认Android 源码中并没有给这些属性配值,所以直接添加上去就可以了.其中,配置文件在设备的 /system/build.prop .
<property name="ro.config.vc_call_vol_default" value="5">
<property name="ro.config.media_vol_default" value="15">
<property name="ro.config.alarm_vol_default" value="7">
<property name="ro.config.system_vol_default" value="7">