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)  {    //在這里不處理position的原因是因為getItem方法在    //instantiateItem方法中調用。只要在調用前處理    //position即可，以免重復處理    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)   {    //處理position。讓數組下標落在[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)      {        //處理position。讓position落在[0,fragmentList.size)中，防止數組越界        position = position % list.size();        ReadFragment fragment= (ReadFragment) list.get(position); //獲得此時選中的fragment        fragment.refreshState(); //翻頁的時候每個頁面需要改變的參數使用這個方法來實現，這個方法在ReadFragment里面，修飾器得使用public        ...      }      @Override      public void onPageScrollStateChanged(int state)      {}    });