Android中有如下几种音频流：

• AudioManager.STREAM_MUSIC  /** The audio stream for music playback */
• AudioManager.STREAM_RING /** The audio stream for the phone ring */
• AudioManager.STREAM_ALARM  /** The audio stream for alarms */
• AudioManager.STREAM_NOTIFICATION /** The audio stream for notifications */
• AudioManager.STREAM_SYSTEM  /** The audio stream for system sounds */
• AudioManager.STREAM_VOICECALL /** The audio stream for phone calls */