修改 Android 5.x 系统默认音量大小

修改系统默认音量需要改两处地方：

1. frameworks\base\media\java\android\media\AudioManager.java

 1 /**  @hide Default volume index values for audio streams */
 2     public static final int[] DEFAULT_STREAM_VOLUME = new int[] {
 3         4,  // STREAM_VOICE_CALL
 4         7,  // STREAM_SYSTEM
 5         5,  // STREAM_RING
 6         8,//11, // STREAM_MUSIC
 7         6,  // STREAM_ALARM
 8         5,  // STREAM_NOTIFICATION
 9         7,  // STREAM_BLUETOOTH_SCO
10         7,  // STREAM_SYSTEM_ENFORCED
11         11, // STREAM_DTMF
12         11,  // STREAM_TTS
13         4   // STREAM_INCALL_MUSIC
14     };

此处的音量值用来生成settings.db数据库字段的值。settings.db数据库在Android 5.x中的路径为/data/data/com.android.providers.settings/database/目录下。

2. frameworks\base\media\java\android\media\AudioService.java

 1 /** @hide Maximum volume index values for audio streams */
 2     private static int[] MAX_STREAM_VOLUME = new int[] {
 3         15,  // STREAM_VOICE_CALL
 4         7,  // STREAM_SYSTEM
 5         7,  // STREAM_RING
 6         15, // STREAM_MUSIC
 7         7,  // STREAM_ALARM
 8         7,  // STREAM_NOTIFICATION
 9         15, // STREAM_BLUETOOTH_SCO
10         7,  // STREAM_SYSTEM_ENFORCED
11         15, // STREAM_DTMF
12         15  // STREAM_TTS
13     };
14
15     private static int[] DEFAULT_STREAM_VOLUME = new int[] {
16         15,  // STREAM_VOICE_CALL
17         7,  // STREAM_SYSTEM
18         5,  // STREAM_RING
19         8,//11, // STREAM_MUSIC
20         6,  // STREAM_ALARM
21         5,  // STREAM_NOTIFICATION
22         7,  // STREAM_BLUETOOTH_SCO
23         7,  // STREAM_SYSTEM_ENFORCED
24         11, // STREAM_DTMF
25         11  // STREAM_TTS
26     };

MAX_STREAM_VOLUME 数组为系统最大音量值。

DEFAULT_STREAM_VOLUME 数组为系统默认音量值。