NativeScript Audio

NativeScript plugin to play and record audio files for Android and iOS.

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Installation

NativeScript 7+:

npm install nativescript-audio

NativeScript Version prior to 7:

tns plugin add nativescript-audio@5.1.1

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Android Native Classes

• Player - android.media.MediaPlayer
• Recorder - android.media.MediaRecorder

iOS Native Classes

• Player - AVAudioPlayer
• Recorder - AVAudioRecorder

Permissions

iOS

You will need to grant permissions on iOS to allow the device to access the microphone if you are using the recording function. If you don't, your app may crash on device and/or your app might be rejected during Apple's review routine. To do this, add this key to your app/App_Resources/iOS/Info.plist file:

<key>NSMicrophoneUsageDescription</key>
<string>Recording Practice Sessions</string>

Android

If you are going to use the recorder capability for Android, you need to add the RECORD_AUDIO permission to your AndroidManifest.xml file located in App_Resources.

    <uses-permission android:name="android.permission.RECORD_AUDIO"/>

Usage

TypeScript Example

import { TNSPlayer } from 'nativescript-audio';

export class YourClass {
  private _player: TNSPlayer;

  constructor() {
    this._player = new TNSPlayer();
    // You can pass a duration hint to control the behavior of other application that may
    // be holding audio focus.
    // For example: new  TNSPlayer(AudioFocusDurationHint.AUDIOFOCUS_GAIN_TRANSIENT);
    // Then when you play a song, the previous owner of the
    // audio focus will stop. When your song stops
    // the previous holder will resume.
    this._player.debug = true; // set true to enable TNSPlayer console logs for debugging.
    this._player
      .initFromFile({
        audioFile: '~/assets/song.mp3', // ~ = app directory
        loop: false,
        completeCallback: this._trackComplete.bind(this),
        errorCallback: this._trackError.bind(this)
      })
      .then(() => {
        this._player.getAudioTrackDuration().then(duration => {
          // iOS: duration is in seconds
          // Android: duration is in milliseconds
          console.log(`song duration:`, duration);
        });
      });
  }

  public togglePlay() {
    if (this._player.isAudioPlaying()) {
      this._player.pause();
    } else {
      this._player.play();
    }
  }

  private _trackComplete(args: any) {
    console.log('reference back to player:', args.player);
    // iOS only: flag indicating if completed succesfully
    console.log('whether song play completed successfully:', args.flag);
  }

  private _trackError(args: any) {
    console.log('reference back to player:', args.player);
    console.log('the error:', args.error);
    // Android only: extra detail on error
    console.log('extra info on the error:', args.extra);
  }

  // This is an example method for watching audio meters and converting the values from Android's arbitrary 
  // value to something close to dB. iOS reports values from -120 to 0, android reports values from 0 to about 37000.
  // The below method converts the values to db as close as I could figure out. You can tweak the .1 value to your discretion.
  // I am basically converting these numbers to something close to a percentage value. My handle Meter UI method
  // converts that value to a value I can use to pulse a circle bigger and smaller, representing your audio level. 
  private _initMeter() {
    this._resetMeter();
    this._meterInterval = this._win.setInterval(() => {
      this.audioMeter = this._recorder.getMeters();
      if (isIOS) {
        this.handleMeterUI(this.audioMeter+200)
      } else {
        let db = (20 * Math.log10(parseInt(this.audioMeter) / .1)); 
        let percentage = db + 85; 
        this.handleMeterUI(percentage)
      }
    }, 150);
  }

  handleMeterUI(percentage) {
    let scale = percentage/100;

    function map_range(value, in_low, in_high, out_low, out_high) {
      return out_low + (out_high - out_low) * (value - in_low) / (in_high - in_low);
    }
    let lerpScale = map_range(scale, 1.2, 1.9, 0.1, 2.1)
    if (scale > 0) {
      this.levelMeterCircleUI.animate({
        scale: {x: lerpScale, y: lerpScale},
        duration: 100
      }).then(() => {}).catch(() => {})
    }
    if (lerpScale > 2.2) {
      this.levelBgColor = 'rgba(255, 0, 0, 1)';
    } else {
      this.levelBgColor = 'rgb(0, 183, 0)';
    }
  }
}

Javascript Example:

const audio = require('nativescript-audio');

const player = new audio.TNSPlayer();
const playerOptions = {
  audioFile: 'http://some/audio/file.mp3',
  loop: false,
  completeCallback: function () {
    console.log('finished playing');
  },
  errorCallback: function (errorObject) {
    console.log(JSON.stringify(errorObject));
  },
  infoCallback: function (args) {
    console.log(JSON.stringify(args));
  }
};

player
  .playFromUrl(playerOptions)
  .then(res => {
    console.log(res);
  })
  .catch(err => {
    console.log('something went wrong...', err);
  });

API

Recorder

TNSRecorder Methods

Method	Description
TNSRecorder.CAN_RECORD(): boolean - static method	Determine if ready to record.
start(options: AudioRecorderOptions): Promise<void>	Start recording to file.
stop(): Promise<void>	Stop recording.
pause(): Promise<void>	Pause recording.
resume(): Promise<void>	Resume recording.
dispose(): Promise<void>	Free up system resources when done with recorder.
getMeters(channel?: number): number	Returns the amplitude of the input.
isRecording(): boolean - iOS Only	Returns true if recorder is actively recording.
requestRecordPermission(): Promise<void>	Android Only Resolves the promise is user grants the permission.
hasRecordPermission(): boolean	Android Only Returns true if RECORD_AUDIO permission has been granted.

TNSRecorder Instance Properties

Property	Description
ios	Get the native AVAudioRecorder class instance.
android	Get the native MediaRecorder class instance.
debug	Set true to enable debugging console logs (default false).

TNSRecorder AudioRecorderOptions

Property	Type	Description
filename	string	Gets or sets the recorded file name.
source	int	Android Only Sets the source for recording. Learn more here https://developer.android.com/reference/android/media/MediaRecorder.AudioSource
maxDuration	int	Gets or set the max duration of the recording session. Input in milliseconds, which is Android's format. Will be converted appropriately for iOS.
metering	boolean	Enables metering. This will allow you to inspect the audio level by calling the record instance's getMeters ,method. This will return dB on iOS, but an arbitrary amplitude number for Android. See the metering example for a way to convert the output to something resembling dB on Android.
format	int or enum	The Audio format to record in. On Android, use these Enums: https://developer.android.com/reference/android/media/AudioFormat#ENCODING_PCM_16BIT On ios, use these format options: https://developer.apple.com/documentation/coreaudiotypes/1572096-audio_format_identifiers
channels	int	Number of channels to record (mono, st)
sampleRate	int	The sample rate to record in. Default: 44100
bitRate	int	Android Only The bitrate to record in. iOS automatically calculates based on iosAudioQuality flag. Default: 128000
encoder	int or enum	Android Only Use https://developer.android.com/reference/android/media/MediaRecorder.AudioEncoder#AAC
iosAudioQuality	string	ios uses AVAudioQuality to determine encoder and bitrate. Accepts Min, Low, Medium, High, Max https://developer.apple.com/documentation/avfaudio/avaudioquality
errorCallback	function	Gets or sets the callback when an error occurs with the media recorder. Returns An object containing the native values for the error callback.
infoCallback	function	Gets or sets the callback to be invoked to communicate some info and/or warning about the media or its playback. Returns An object containing the native values for the info callback.

Player

TNSPlayer Methods

Method	Description
initFromFile(options: AudioPlayerOptions): Promise	Initialize player instance with a file without auto-playing.
playFromFile(options: AudioPlayerOptions): Promise	Auto-play from a file.
initFromUrl(options: AudioPlayerOptions): Promise	Initialize player instance from a url without auto-playing.
playFromUrl(options: AudioPlayerOptions): Promise	Auto-play from a url.
pause(): Promise<boolean>	Pause playback.
resume(): void	Resume playback.
seekTo(time:number): Promise<boolean>	Seek to position of track (in seconds).
dispose(): Promise<boolean>	Free up resources when done playing audio.
isAudioPlaying(): boolean	Determine if player is playing.
getAudioTrackDuration(): Promise<string>	Duration of media file assigned to the player.
playAtTime(time: number): void - iOS Only	Play audio track at specific time of duration.
changePlayerSpeed(speed: number): void - On Android Only API 23+	Change the playback speed of the media player.

TNSPlayer Instance Properties

Property	Description
ios	Get the native ios AVAudioPlayer instance.
android	Get the native android MediaPlayer instance.
debug: boolean	Set true to enable debugging console logs (default false).
currentTime: number	Get the current time in the media file's duration.
volume: number	Get/Set the player volume. Value range from 0 to 1.

License

MIT

Demo App

• fork/clone the repository
• cd into the src directory
• execute npm run demo.android or npm run demo.ios (scripts are located in the scripts of the package.json in the src directory if you are curious)