思路参考https://github.com/zhongbaitu/WaveLoadingView，
只是自己动手实现，当作练手。

my.gif

<pre>
public class CustomWaveLoadingView extends View
{

private Paint mWavePaint;
private int mWaveColor = 0xff0099CC;
private Path path;

// 左右偏移 φ
private int fai = 0;
// 上下偏移
private volatile float k = -50;
// 角速度
private float w = 0.5f;
// 振幅
private int a = 20;
//控件高
private int mViewHeight;
//控件宽
private int mViewWidth;
//目标高度
private float mTargetHeight;
// 0% 时，空白的高度
private float mBaseBlank;
// 绘制间隔时间
private int mInterval = 4;
//是否继续绘制
private volatile boolean mIsRun = true;
//是否初始化
private boolean mIsFirst = true;

Runnable mDrawAuto = new Runnable()
{
    @Override
    public void run()
    {
        while (mIsRun)
        {
            fai++;
            if (fai == 360)
            {
                fai = 0;
            }


            if (k > mTargetHeight)
            {

                k--;
            }

            mDrawHandler.sendEmptyMessage(1);

            try
            {
                Thread.sleep(mInterval);
            } catch (InterruptedException e)
            {
                e.printStackTrace();
            }


        }
    }
};

Handler mDrawHandler = new Handler()
{
    @Override
    public void handleMessage(Message msg)
    {
        invalidate();
        super.handleMessage(msg);
    }
};

public CustomWaveLoadingView(Context context)
{
    this(context, null);
}

public CustomWaveLoadingView(Context context, AttributeSet attrs)
{
    this(context, attrs, 0);
}

public CustomWaveLoadingView(Context context, AttributeSet attrs, int defStyleAttr)
{
    super(context, attrs, defStyleAttr);
    init();
}

private void init()
{
    //初始化波浪画笔
    mWavePaint = new Paint();
    mWavePaint.setAntiAlias(true);
    mWavePaint.setColor(mWaveColor);

    path = new Path();

}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    initData();
}

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

private void initData()
{
    if (mIsFirst)
    {
        mViewWidth = getMeasuredWidth();
        mViewHeight = getMeasuredHeight();
        mBaseBlank = (float) (mViewHeight * 0.9);
        mTargetHeight = (float) (mBaseBlank * 0.2);
        k = mBaseBlank;
        new Thread(mDrawAuto).start();
        mIsFirst = false;
    }

}

@Override
protected void onDraw(Canvas canvas)
{
    super.onDraw(canvas);
    setPath();
    canvas.drawPath(path, mWavePaint);
}

private void setPath()
{
    path.reset();
    int x = 0;
    int y = 0;
    for (int i = 0; i < mViewWidth; i++)
    {
        x = i;
        y = (int) (a * Math.sin((i * w + fai) * Math.PI / 180) + k);
        if (i == 0)
        {
            path.moveTo(x, y);
        }

        path.quadTo(x, y, x + 1, y);
    }

    path.lineTo(mViewWidth, mViewHeight);
    path.lineTo(0, mViewHeight);
    path.close();
}

}
</code></pre>