How to Get a soundcloud like waveforms in Android

问题:

I have generated a simple waveform like the picture below with my code.

But I want to give more gap between each line I want it to be like the soundcloud waves like the picutre below.

Here is my code:

public class VisualizerView extends View {
    private static final int LINE_WIDTH = 15; // width of visualizer lines
    private static final int LINE_SCALE = 55; // scales visualizer lines
    private List<Float> amplitudes; // amplitudes for line lengths
    private int width; // width of this View
    private int height; // height of this View
    private Paint linePaint; // specifies line drawing characteristics

    // constructor
    public VisualizerView(Context context, AttributeSet attrs) {
        super(context, attrs); // call superclass constructor
        linePaint = new Paint(); // create Paint for lines
        linePaint.setColor(Color.parseColor("#a4410e")); // set color to green
        linePaint.setStrokeWidth(LINE_WIDTH); // set stroke width
    }

    // called when the dimensions of the View change
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        width = w; // new width of this View
        height = h; // new height of this View
        amplitudes = new ArrayList<Float>(width / LINE_WIDTH);
    }

    // clear all amplitudes to prepare for a new visualization
    public void clear() {
        amplitudes.clear();
    }

    // add the given amplitude to the amplitudes ArrayList
    public void addAmplitude(float amplitude) {
        amplitudes.add(amplitude); // add newest to the amplitudes ArrayList

        // if the power lines completely fill the VisualizerView
        if (amplitudes.size() * LINE_WIDTH >= width) {
            amplitudes.remove(0); // remove oldest power value
        }
    }

    // draw the visualizer with scaled lines representing the amplitudes
    @Override
    public void onDraw(Canvas canvas) {
        int middle = height / 2; // get the middle of the View
        float curX = 0; // start curX at zero

        // for each item in the amplitudes ArrayList
        for (float power : amplitudes) {
            float scaledHeight = power / LINE_SCALE; // scale the power
            curX += LINE_WIDTH; // increase X by LINE_WIDTH

            Log.e("crux",String.valueOf(curX));

            // draw a line representing this item in the amplitudes ArrayList
            canvas.drawLine(curX, middle + scaledHeight / 2, curX, middle
                    - scaledHeight / 2, linePaint);
        }
    }

}

Stuck on it from so many hours please someone get me out of it

回答1:

I tried the random changes in your code and got the desired output you needed

by changing these two lines

private static final int LINE_WIDTH = 2  (from 15 to 2); // width of visualizer lines
curX += LINE_WIDTH+5; // increase X by LINE_WIDTH (adding +5)

---

public class VisualizerView extends View {
    private static final int LINE_WIDTH = 2; // width of visualizer lines
    private static final int LINE_SCALE = 55; // scales visualizer lines
    private List<Float> amplitudes; // amplitudes for line lengths
    private int width; // width of this View
    private int height; // height of this View
    private Paint linePaint; // specifies line drawing characteristics

    // constructor
    public VisualizerView(Context context, AttributeSet attrs) {
        super(context, attrs); // call superclass constructor
        linePaint = new Paint(); // create Paint for lines
        linePaint.setColor(Color.parseColor("#a4410e")); // set color to green
        linePaint.setStrokeWidth(LINE_WIDTH); // set stroke width
    }

    // called when the dimensions of the View change
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        width = w; // new width of this View
        height = h; // new height of this View
        amplitudes = new ArrayList<Float>(width / LINE_WIDTH);
    }

    // clear all amplitudes to prepare for a new visualization
    public void clear() {
        amplitudes.clear();
    }

    // add the given amplitude to the amplitudes ArrayList
    public void addAmplitude(float amplitude) {
        amplitudes.add(amplitude); // add newest to the amplitudes ArrayList

        // if the power lines completely fill the VisualizerView
        if (amplitudes.size() * LINE_WIDTH >= width) {
            amplitudes.remove(0); // remove oldest power value
        }
    }

    // draw the visualizer with scaled lines representing the amplitudes
    @Override
    public void onDraw(Canvas canvas) {
        int middle = height / 2; // get the middle of the View
        float curX = 0; // start curX at zero

        // for each item in the amplitudes ArrayList
        for (float power : amplitudes) {
            float scaledHeight = power / LINE_SCALE; // scale the power
            curX += LINE_WIDTH+5; // increase X by LINE_WIDTH

            Log.e("crux",String.valueOf(curX));

            // draw a line representing this item in the amplitudes ArrayList
            canvas.drawLine(curX, middle + scaledHeight / 2, curX, middle
                    - scaledHeight / 2, linePaint);
        }
    }

}