Using TonePlayer for Audio Playback (for System Applications Only)

TonePlayer⁹⁺ provides APIs for playing and managing Dual Tone Multi Frequency (DTMF) tones, such as dial tones, ringback tones, supervisory tones, and proprietary tones. The main task of the TonePlayer is to generate sine waves of different frequencies by using the built-in algorithm based on the ToneType and add the sine waves to create a sound. The sound can then be played by using the AudioRenderer, and the playback task can also be managed by using the AudioRenderer. The full process includes loading the DTMF tone configuration, starting DTMF tone playing, stopping the playback, and releasing the resources associated with the TonePlayer object. For details about the APIs, see the TonePlayer API Reference.

Supported Tone Types

The table below lists the supported ToneTypes. You can call load() with audio.ToneType.*type* as a parameter to load the tone resource of the specified type.

How to Develop

To implement audio playback with the TonePlayer, perform the following steps:

1. Create a TonePlayer instance.

   import audio from '@ohos.multimedia.audio';
   let audioRendererInfo: audio.AudioRendererInfo = {
     usage : audio.StreamUsage.STREAM_USAGE_DTMF,
     rendererFlags : 0
   };
   async function createTonePlayer() {
     let tonePlayerPromise = await audio.createTonePlayer(audioRendererInfo);
   }

1. Load the DTMF tone configuration of the specified type.

   async function load() {
       await tonePlayerPromise.load(audio.ToneType.TONE_TYPE_DIAL_0);
   }

1. Start DTMF tone playing.

   async function start() {
       await tonePlayerPromise.start();
   }

1. Stop the tone that is being played.

   async function stop() {
       await tonePlayerPromise.stop();
   }

1. Release the resources associated with the TonePlayer instance.

   async function release() {
       await tonePlayerPromise.release();
   }

If the APIs are not called in the preceding sequence, the error code 6800301 NAPI_ERR_SYSTEM is returned.

Sample Code

Refer to the following code to play the DTMF tone when the dial key on the keyboard is pressed.

To prevent the UI thread from being blocked, most TonePlayer calls are asynchronous. Each API provides the callback and promise functions. The following examples use the promise functions. For more information, see TonePlayer.

import audio from '@ohos.multimedia.audio';
import { BusinessError } from '@ohos.base';


let timerPro : number;
// Promise mode.
async function testTonePlayerPromise(type: audio.ToneType) {
  console.info('testTonePlayerPromise start');
  if (timerPro) clearTimeout(timerPro);
  let tonePlayerPromise: audio.TonePlayer;
  let audioRendererInfo: audio.AudioRendererInfo = {
    usage : audio.StreamUsage.STREAM_USAGE_DTMF,
    rendererFlags : 0
  };
  timerPro = setTimeout(async () => {
    try {
      console.info('testTonePlayerPromise: createTonePlayer');
      // Create a DTMF player.     
      tonePlayerPromise = await audio.createTonePlayer(audioRendererInfo);
      console.info('testTonePlayerPromise: createTonePlayer-success');
      console.info(`testTonePlayerPromise: load type: ${type}`);
      // Load the tone configuration of the specified type.
      await tonePlayerPromise.load(type);
      console.info('testTonePlayerPromise: load-success');
      console.info(`testTonePlayerPromise: start type: ${type}`);
      // Start DTMF tone playing.
      await tonePlayerPromise.start();
      console.info('testTonePlayerPromise: start-success');
      console.info(`testTonePlayerPromise: stop type: ${type}`);
      setTimeout(async()=>{
        // Stop the tone that is being played.
        await tonePlayerPromise.stop();
        console.info('testTonePlayerPromise: stop-success');
        console.info(`testTonePlayerPromise: release type: ${type}`);
        // Release the resources associated with the TonePlayer instance.
        await tonePlayerPromise.release();
        console.info('testTonePlayerPromise: release-success');
      }, 30)
    } catch(err) {
      let error = err as BusinessError;
      console.error(`testTonePlayerPromise err : ${error}`);
    }
  }, 200)
};

async function testTonePlayer() {
   testTonePlayerPromise(audio.ToneType.TONE_TYPE_DIAL_0);
}

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