Audio control - Android

In Android apps, you should always be able to control audio. When using MediaPlayer, you should implement buttons to call the start, pause and stop methods.

It is a best practice to play audio through the correct channel. Android has introduced AudioAttributes as a replacement of the STREAM types defined in AudioManager.

AudioAttributes defines the following content types:

• CONTENT_TYPE_MOVIE: used for soundtracks, typically in movies
• CONTENT_TYPE_MUSIC: used for music
• CONTENT_TYPE_SONIFICATION: used for accompanying sounds, such as beeps
• CONTENT_TYPE_SPEECH: used for speech
• CONTENT_TYPE_UNKNOWN: used when the content type is unknown, or other than the available options

AudioAttributes defines the following usages:

• USAGE_ALARM: used for alarms
• USAGE_ASSISTANCE_ACCESSIBILITY: used for accessibility, e.g. for screen reader users
• USAGE_ASSISTANCE_NAVIGATION_GUIDANCE: used for navigation directions, e.g. while driving
• USAGE_ASSISTANCE_SONIFICATION: used for user interface sounds
• USAGE_ASSISTANT: used for user queries, audio instructions or help utterances.
• USAGE_GAME: used for audio inside games
• USAGE_MEDIA: used for audio in media, such as movies
• USAGE_NOTIFICATION: used for notification sounds
• USAGE_NOTIFICATION_EVENT: used to attract the user's attention, such as a reminder or low battery warning.
• USAGE_NOTIFICATION_RINGTONE: used for telephony ringtones
• USAGE_UNKNOWN: used when the usage is unknown, or not defined
• USAGE_VOICE_COMMUNICATION: used for voice communication, such as telephony or VoIP
• USAGE_VOICE_COMMUNICATION_SIGNALLING: used for in-call signalling, such as with a "busy" beep, or DTMF tones.

AudioManager defines the following legacy channels:

• STREAM_ACCESSIBILITY: channel for accessibility, such as assistive technologies
• STREAM_ALARM: channel for alarms
• STREAM_DMTF: channel for dual-tone multi-frequency signaling, such as phone dialing tones
• STREAM_MUSIC: channel for music
• STREAM_NOTIFICATION: channel for notifications
• STREAM_RING: channel for incoming phone calls
• STREAM_SYSTEM: channel for system sounds
• STREAM_VOICE_CALL: channel for voice calls

// Set audio attributes
val player = MediaPlayer()
player.setAudioAttributes(
    AudioAttributes.Builder()
        .setUsage(AudioAttributes.USAGE_ASSISTANCE_ACCESSIBILITY)
        .setContentType(AudioAttributes.CONTENT_TYPE_SPEECH)
        .setLegacyStreamType(AudioManager.STREAM_ACCESSIBILITY)
        .build()
)

// Provide media controls
button.setOnClickListener {
    if (player.isPlaying()) {
        player.pause()
    } else {
        player.start()
    }
}