Android 12 修改系统音量默认初始值

本文介绍: (2)步骤二:由于Aud ioServ ice.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.在Aud ioSyste m.Jav a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.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.

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.java

3.系统音量默认初始值在AudioSyste m.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AudioServ ice.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 &amp;&amp;
                defaultCallVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] &amp;&amp;
                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 &amp;&amp;
                defaultMusicVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] &amp;&amp;
                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 &amp;&amp;
                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 &amp;&amp;
                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 &amp;&
                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">