android - ven - Mostrar forma de onda de audio

programa para captar ondas de sonido

Question

Estoy haciendo una aplicación de música en Android. En esta lista de música que viene del lado del servidor. ¿No sé cómo mostrar la forma de onda del audio en Android? Como en el sitio web de soundcloud. He adjuntado la imagen a continuación.

Answer 1

Tal vez, puede implementar esta función sin bibliotecas, por supuesto, si solo desea la visualización de muestras de audio. Por ejemplo:

public class PlayerVisualizerView extends View {

    /**
     * constant value for Height of the bar
     */
    public static final int VISUALIZER_HEIGHT = 28;

    /**
     * bytes array converted from file.
     */
    private byte[] bytes;

    /**
     * Percentage of audio sample scale
     * Should updated dynamically while audioPlayer is played
     */
    private float denseness;

    /**
     * Canvas painting for sample scale, filling played part of audio sample
     */
    private Paint playedStatePainting = new Paint();
    /**
     * Canvas painting for sample scale, filling not played part of audio sample
     */
    private Paint notPlayedStatePainting = new Paint();

    private int width;
    private int height;

    public PlayerVisualizerView(Context context) {
        super(context);
        init();
    }

    public PlayerVisualizerView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    private void init() {
        bytes = null;

        playedStatePainting.setStrokeWidth(1f);
        playedStatePainting.setAntiAlias(true);
        playedStatePainting.setColor(ContextCompat.getColor(getContext(), R.color.gray));
        notPlayedStatePainting.setStrokeWidth(1f);
        notPlayedStatePainting.setAntiAlias(true);
        notPlayedStatePainting.setColor(ContextCompat.getColor(getContext(), R.color.colorAccent));
    }

    /**
     * update and redraw Visualizer view
     */
    public void updateVisualizer(byte[] bytes) {
        this.bytes = bytes;
        invalidate();
    }

    /**
     * Update player percent. 0 - file not played, 1 - full played
     *
     * @param percent
     */
    public void updatePlayerPercent(float percent) {
        denseness = (int) Math.ceil(width * percent);
        if (denseness < 0) {
            denseness = 0;
        } else if (denseness > width) {
            denseness = width;
        }
        invalidate();
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
        width = getMeasuredWidth();
        height = getMeasuredHeight();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if (bytes == null || width == 0) {
            return;
        }
        float totalBarsCount = width / dp(3);
        if (totalBarsCount <= 0.1f) {
            return;
        }
        byte value;
        int samplesCount = (bytes.length * 8 / 5);
        float samplesPerBar = samplesCount / totalBarsCount;
        float barCounter = 0;
        int nextBarNum = 0;

        int y = (height - dp(VISUALIZER_HEIGHT)) / 2;
        int barNum = 0;
        int lastBarNum;
        int drawBarCount;

        for (int a = 0; a < samplesCount; a++) {
            if (a != nextBarNum) {
                continue;
            }
            drawBarCount = 0;
            lastBarNum = nextBarNum;
            while (lastBarNum == nextBarNum) {
                barCounter += samplesPerBar;
                nextBarNum = (int) barCounter;
                drawBarCount++;
            }

            int bitPointer = a * 5;
            int byteNum = bitPointer / Byte.SIZE;
            int byteBitOffset = bitPointer - byteNum * Byte.SIZE;
            int currentByteCount = Byte.SIZE - byteBitOffset;
            int nextByteRest = 5 - currentByteCount;
            value = (byte) ((bytes[byteNum] >> byteBitOffset) & ((2 << (Math.min(5, currentByteCount) - 1)) - 1));
            if (nextByteRest > 0) {
                value <<= nextByteRest;
                value |= bytes[byteNum + 1] & ((2 << (nextByteRest - 1)) - 1);
            }

            for (int b = 0; b < drawBarCount; b++) {
                int x = barNum * dp(3);
                float left = x;
                float top = y + dp(VISUALIZER_HEIGHT - Math.max(1, VISUALIZER_HEIGHT * value / 31.0f));
                float right = x + dp(2);
                float bottom = y + dp(VISUALIZER_HEIGHT);
                if (x < denseness && x + dp(2) < denseness) {
                    canvas.drawRect(left, top, right, bottom, notPlayedStatePainting);
                } else {
                    canvas.drawRect(left, top, right, bottom, playedStatePainting);
                    if (x < denseness) {
                        canvas.drawRect(left, top, right, bottom, notPlayedStatePainting);
                    }
                }
                barNum++;
            }
        }
    }

    public int dp(float value) {
        if (value == 0) {
            return 0;
        }
        return (int) Math.ceil(getContext().getResources().getDisplayMetrics().density * value);
    }
}

Lo sentimos, codifique con una pequeña cantidad de comentarios, pero está funcionando el visualizador. Puedes adjuntarlo a cualquier jugador que quieras.

Cómo puede usarlo: agregue esta vista en su diseño xml, luego debe actualizar el estado del visualizador con métodos

public void updateVisualizer(byte[] bytes) {
    playerVisualizerView.updateVisualizer(bytes);
}

public void updatePlayerProgress(float percent) {
    playerVisualizerView.updatePlayerPercent(percent);
}

En updateVisualizer usted pasa la matriz de bytes con su muestra de audio, y en updatePlayerProgress pasa un porcentaje dinámico, mientras se reproduce la muestra de audio.

para convertir archivos a bytes puede usar este método auxiliar

public static byte[] fileToBytes(File file) {
    int size = (int) file.length();
    byte[] bytes = new byte[size];
    try {
        BufferedInputStream buf = new BufferedInputStream(new FileInputStream(file));
        buf.read(bytes, 0, bytes.length);
        buf.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return bytes;
}

y por ejemplo (muy pronto), cómo se ve con la biblioteca Mosby:

public class AudioRecorderPresenter extends MvpBasePresenter<AudioRecorderView> {

public void onStopRecord() {
        // stopped and released MediaPlayer
        // ...
        // some preparation and saved audio file in audioFileName variable.

        getView().updateVisualizer(FileUtils.fileToBytes(new File(audioFileName)));
        }
    }
}