ViewPager结合Fragment进行无限滑动

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.view.ViewGroup;

import java.util.ArrayList;

public class adapter extends FragmentPagerAdapter
{
    private ArrayList<Fragment> fragmentList;
    public adapter(FragmentManager fm)
    {
        super(fm);
    }
    public adapter(FragmentManager fm, ArrayList<Fragment> fragmentList)
    {
        super(fm);
        this.fragmentList=fragmentList;
    }
    @Override
    public Fragment getItem(int position)
    {
        //在这里不处理position的原因是因为getItem方法在
        //instantiateItem方法中调用。只要在调用前处理
        //position即可，以免重复处理

        return fragmentList.get(position);
    }

    @Override
    public int getCount() 
    {
        return Integer.MAX_VALUE;
    }

    @Override
    public int getItemPosition(Object object) 
    {
        return super.getItemPosition(object);
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) 
    {
        //处理position。让数组下标落在[0,fragmentList.size)中，防止越界
        position = position % fragmentList.size();

        return super.instantiateItem(container, position);
    }

}

        Fragment a=new ReadFragment();
        Fragment b=new ReadFragment();
        Fragment c=new ReadFragment();
        Fragment d=new ReadFragment();

        list=new ArrayList<Fragment>();
        list.add(a);
        list.add(b);
        list.add(c);
        list.add(d);

        readViewPager.setAdapter(new adapter(getSupportFragmentManager(),list));

readViewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener()
        {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels)
            {}

            @Override
            public void onPageSelected(int position)
            {
                //处理position。让position落在[0,fragmentList.size)中，防止数组越界
                position = position % list.size();
                ReadFragment fragment= (ReadFragment) list.get(position); //获得此时选中的fragment
                fragment.refreshState(); //翻页的时候每个页面需要改变的参数使用这个方法来实现，这个方法在ReadFragment里面，修饰器得使用public
                ...
            }

            @Override
            public void onPageScrollStateChanged(int state)
            {}
        });