AudioManagerCompat

public static final int AUDIOFOCUS_GAIN = 1

Used to indicate a gain of audio focus, or a request of audio focus, of unknown duration.

public static final int AUDIOFOCUS_GAIN_TRANSIENT = 2

Used to indicate a temporary gain or request of audio focus, anticipated to last a short amount of time. Examples of temporary changes are the playback of driving directions, or an event notification.

public static final int AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE = 4

Used to indicate a temporary request of audio focus, anticipated to last a short amount of time, during which no other applications, or system components, should play anything. Examples of exclusive and transient audio focus requests are voice memo recording and speech recognition, during which the system shouldn't play any notifications, and media playback should have paused.

public static final int AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK = 3

Used to indicate a temporary request of audio focus, anticipated to last a short amount of time, and where it is acceptable for other audio applications to keep playing after having lowered their output level (also referred to as "ducking"). Examples of temporary changes are the playback of driving directions where playback of music in the background is acceptable.

public static int abandonAudioFocusRequest(
    @NonNull AudioManager audioManager,
    @NonNull AudioFocusRequestCompat focusRequest
)

Abandon audio focus. Causes the previous focus owner, if any, to receive focus.

public static @IntRange(from = 0) int getStreamMaxVolume(@NonNull AudioManager audioManager, int streamType)

Returns the maximum volume index for a particular stream.

public static @IntRange(from = 0) int getStreamMinVolume(@NonNull AudioManager audioManager, int streamType)

Returns the minimum volume index for a particular stream.

public static boolean isVolumeFixed(@NonNull AudioManager audioManager)

Indicates if the device implements a fixed volume policy.

Some devices may not have volume control and may operate at a fixed volume, and may not enable muting or changing the volume of audio streams. This method will return true on such devices.

Compatibility: It returns false on API level below 21 even if the device has fixed volume.

public static int requestAudioFocus(
    @NonNull AudioManager audioManager,
    @NonNull AudioFocusRequestCompat focusRequest
)

Requests audio focus. See the AudioFocusRequestCompat for information about the options available to configure your request, and notification of focus gain and loss.