利用ViewPager如何判断划动方向

//记录上一次滑动的positionOffsetPixels值  private int lastValue = -1;   private boolean isLeft = true; mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {    @Override    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {      if (positionOffset != 0) {        if (lastValue >= positionOffsetPixels) {          //右滑          isLeft = false;        } else if (lastValue < positionOffsetPixels) {          //左滑          isLeft = true;        }        setIndiactorView(positionOffset,isLeft);      }      lastValue = positionOffsetPixels;    }    @Override    public void onPageSelected(int position) {      if (isLeft){        Log.e("onPageScrolled","--->左划");      }else {        Log.e("onPageScrolled","--->右划");      }    }    @Override    public void onPageScrollStateChanged(int state) {    }  });