Android AudioManager修改设备默认音量

Android 4.4：

修改AudioManager中的默认音量数组：

frameworks/base/media/java/android/media/AudioManager.java

public static final int[] DEFAULT_STREAM_VOLUME = new int[] {
4, // STREAM_VOICE_CALL
7, // STREAM_SYSTEM
4, // STREAM_RING
8, // STREAM_MUSIC
4, // STREAM_ALARM
4, // STREAM_NOTIFICATION
7, // STREAM_BLUETOOTH_SCO
7, // STREAM_SYSTEM_ENFORCED
11, // STREAM_DTMF
11, // STREAM_TTS
4, // STREAM_FM
4 // STREAM_MATV
};

Android 5.1：

AudioManager中没有4.4中的DEFAULT_STREAM_VOLUME 数组，移动到了AudioService：

frameworks/base/media/java/android/media/AudioService.java

/**
* @hide Default volume index values for audio streams
* M: modify the default stream volume @{
*/
public static int[] DEFAULT_STREAM_VOLUME = new int[] {
4,  // STREAM_VOICE_CALL
15,  // STREAM_SYSTEM
8,  // STREAM_RING
8, // STREAM_MUSIC
8,  // STREAM_ALARM
8,  // STREAM_NOTIFICATION
7,  // STREAM_BLUETOOTH_SCO
15,  // STREAM_SYSTEM_ENFORCED
11, // STREAM_DTMF
11,  // STREAM_TTS
};
/** @ */

附：最大音量

/** @hide Maximum volume index values for audio streams */
/// M: Modify the max stream volume @{
private static final int[] MAX_STREAM_VOLUME = new int[] {
6, // STREAM_VOICE_CALL
15, // STREAM_SYSTEM
15, // STREAM_RING
15, // STREAM_MUSIC
15, // STREAM_ALARM
15, // STREAM_NOTIFICATION
15, // STREAM_BLUETOOTH_SCO
15, // STREAM_SYSTEM_ENFORCED
15, // STREAM_DTMF
15, // STREAM_TTS
};
/// @}