音量概念

音量层级

系统音量：范围0-15（特殊类型是1-15，例如闹钟，通话）。所有应用都可以查询系统音量，仅允许也有system权限的应用修改系统音量。

音量类型

enum AudioVolumeType {
/**
* Audio streams for voice calls.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @since 8
/
/*
* Audio streams for voice calls.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @crossplatform
* @since 12
/
VOICE_CALL = 0,
/*
* Audio streams for ringtones.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @since 7
/
/*
* Audio streams for ringtones.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @crossplatform
* @since 12
/
RINGTONE = 2,
/*
* Audio streams for media purpose.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @since 7
/
/*
* Audio streams for media purpose.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @crossplatform
* @since 12
/
MEDIA = 3,
/*
* Audio volume for alarm purpose.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @since 10
/
/*
* Audio volume for alarm purpose.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @crossplatform
* @since 12
/
ALARM = 4,
/*
* Audio volume for accessibility purpose.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @since 10
/
/*
* Audio volume for accessibility purpose.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @crossplatform
* @since 12
/
ACCESSIBILITY = 5,
/*
* Audio stream for voice assistant.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @since 8
/
VOICE_ASSISTANT = 9,
/*
* Audio volume for ultrasonic.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @systemapi
* @since 10
/
ULTRASONIC = 10,
/*
* Audio stream for all common.
* @syscap SystemCapability.Multimedia.Audio.Volume
* @systemapi
* @since 9
*/
ALL = 100,
}

设置音量：setvolume