波浪效果的实现

package com.loaderman.customviewdemo;

import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.LinearInterpolator;


public class AnimWaveView extends View {
    private Paint mPaint;
    private Path mPath;
    private int mItemWaveLength = 1200;
    private int dx;

    public AnimWaveView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mPath = new Path();
        mPaint = new Paint();
        mPaint.setColor(Color.GREEN);
        mPaint.setStyle(Paint.Style.FILL);

        ValueAnimator animator = ValueAnimator.ofInt(0, mItemWaveLength);
        animator.setDuration(3000);
        animator.setRepeatCount(ValueAnimator.INFINITE);
        animator.setInterpolator(new LinearInterpolator());
        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            public void onAnimationUpdate(ValueAnimator animation) {
                dx = (Integer) animation.getAnimatedValue();
                postInvalidate();
            }
        });
        animator.start();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawColor(Color.WHITE);
        mPath.reset();
        int originY = 300;
        int halfWaveLen = mItemWaveLength / 2;
        mPath.moveTo(-mItemWaveLength + dx, originY);
        for (int i = -mItemWaveLength; i <= getWidth() + mItemWaveLength; i += mItemWaveLength) {
            mPath.rQuadTo(halfWaveLen / 2, -100, halfWaveLen, 0);
            mPath.rQuadTo(halfWaveLen / 2, 100, halfWaveLen, 0);
        }
        mPath.lineTo(getWidth(), getHeight());
        mPath.lineTo(0, getHeight());
        mPath.close();

        canvas.drawPath(mPath, mPaint);
    }

}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <com.loaderman.customviewdemo.AnimWaveView
        android:layout_width="match_parent"

        android:layout_height="300dp" />


</LinearLayout>

效果