public class WaveView extends View { private Paint mPaint; private final Path mPath; //波长 private int wavelength = 500; private int originY=800; private int dx,dy; public WaveView(Context context, @Nullable AttributeSet attrs) { super(context, attrs); mPaint = new Paint(); mPath = new Path(); mPaint.setColor(Color.GREEN); mPaint.setStrokeWidth(5); mPaint.setStyle(Paint.Style.FILL_AND_STROKE);// startanimation(); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); //重置path mPath.reset();// 改变y的起始坐标 if(dy<originY+150){ dy+=10; } int halfWaveLength = wavelength / 2; mPath.moveTo(-wavelength + dx, originY-dy); //屏幕多宽，画多少 for (int i = -wavelength; i <= getWidth() + wavelength; i += wavelength) { /** * 相对绘制二阶贝塞尔曲线（相对于自己的起始点--也即是上一个曲线的终点 ） * float dx1 相对于上一个曲线的终点 的距离 * float dy1 * float dx2 * float dy2 */ mPath.rQuadTo(halfWaveLength / 2, -150, halfWaveLength, 0); mPath.rQuadTo(halfWaveLength / 2, 150, halfWaveLength, 0); } //颜色填充 //画一个封闭的空间 mPath.lineTo(getWidth(), getHeight()); mPath.lineTo(0, getHeight()); mPath.close(); canvas.drawPath(mPath, mPaint);// //设置起始点坐标// path.moveTo(100,400);// //二阶贝塞尔曲线1// path.quadTo(250,200,400,400);// //二阶贝塞尔曲线2// path.quadTo(550,600,700,400);// //关闭路径（将起点和终点闭合）// path.close();// path.moveTo(100,700);// path.cubicTo(50,500,550,500,700,700); } public void startanimation() { ValueAnimator animator = ValueAnimator.ofInt(0, wavelength); animator.setDuration(1000); animator.setInterpolator(new LinearInterpolator()); //无限循环 animator.setRepeatCount(ValueAnimator.INFINITE); animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { dx = (int) animation.getAnimatedValue(); postInvalidate(); } }); animator.start(); }} 
