Android：如何生成频率？

Android中是否有一种很好的方法来生成并播放频率（例如1000hz、245hz）？

看看Android.media

您也可以尝试以下代码

public class PlaySound extends Activity {
    // originally from http://marblemice.blogspot.com/2010/04/generate-and-play-tone-in-android.html
    // and modified by Steve Pomeroy <steve@staticfree.info>
    private final int duration = 3; // seconds
    private final int sampleRate = 8000;
    private final int numSamples = duration * sampleRate;
    private final double sample[] = new double[numSamples];
    private final double freqOfTone = 440; // hz

    private final byte generatedSnd[] = new byte[2 * numSamples];

    Handler handler = new Handler();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    @Override
    protected void onResume() {
        super.onResume();

        // Use a new tread as this can take a while
        final Thread thread = new Thread(new Runnable() {
            public void run() {
                genTone();
                handler.post(new Runnable() {

                    public void run() {
                        playSound();
                    }
                });
            }
        });
        thread.start();
    }

    void genTone(){
        // fill out the array
        for (int i = 0; i < numSamples; ++i) {
            sample[i] = Math.sin(2 * Math.PI * i / (sampleRate/freqOfTone));
        }

        // convert to 16 bit pcm sound array
        // assumes the sample buffer is normalised.
        int idx = 0;
        for (final double dVal : sample) {
            // scale to maximum amplitude
            final short val = (short) ((dVal * 32767));
            // in 16 bit wav PCM, first byte is the low order byte
            generatedSnd[idx++] = (byte) (val & 0x00ff);
            generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);

        }
    }

    void playSound(){
        final AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
                sampleRate, AudioFormat.CHANNEL_CONFIGURATION_MONO,
                AudioFormat.ENCODING_PCM_16BIT, numSamples,
                AudioTrack.MODE_STATIC);
        audioTrack.write(generatedSnd, 0, generatedSnd.length);
        audioTrack.play();
    }
}

public class PlaySound扩展活动{
//源于http://marblemice.blogspot.com/2010/04/generate-and-play-tone-in-android.html
//由史蒂夫·波默罗伊修改
私有最终整数持续时间=3；//秒
私人最终int采样器=8000；
私有最终整数样本=持续时间*采样器；
私人最终双样本[]=新双样本[numSamples]；
专用最终双频通=440；//hz
生成的私有最终字节SND[]=新字节[2*个样本]；
Handler=newhandler（）；
@凌驾
创建时的公共void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.main）；
}
@凌驾
受保护的void onResume（）{
super.onResume（）；
//使用新胎面，因为这可能需要一段时间
最终线程线程=新线程（新可运行（）{
公开募捐{
庚酮（）；
handler.post（新的Runnable（）{
公开募捐{
播放声音（）；
}
});
}
});
thread.start（）；
}
void genTone（）{
//填写数组
对于（int i=0；i>>8）；
}
}
void playSound（）{
最终音轨音轨=新音轨（AudioManager.STREAM_MUSIC，
采样器，AudioFormat.CHANNEL\u配置\u单声道，
AudioFormat.ENCODING_PCM_16位，数字样本，
音频跟踪模式（静态）；
audioTrack.write（generatedSnd，0，generatedSnd.length）；
音轨播放（）；
}
}