BaseFragmentStatePagerAdapter

public class BaseFragmentStatePagerAdapter extends FragmentStatePagerAdapter {

    private FragmentManager mFragmentManager;
    private List<Fragment> mFragments=new ArrayList<>();
    
    public BaseFragmentStatePagerAdapter(FragmentManager fm){
        super(fm);
    }
    
    public BaseFragmentStatePagerAdapter(FragmentManager fm,List<Fragment> fragments){
        super(fm);
        this.mFragmentManager = fm;
        mFragments.clear();
        mFragments.addAll(fragments);
    }
    
    
    @Override
    public int getCount() {
        return mFragments.size();
    }

    @Override
    public Fragment getItem(int position) {
        return mFragments.get(position);
    }

    @Override
    public int getItemPosition(Object object) {
        if (!((Fragment) object).isAdded() || !mFragments.contains(object)) {
            return PagerAdapter.POSITION_NONE;
        }
        return mFragments.indexOf(object);
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        Fragment instantiateItem = ((Fragment) super.instantiateItem(container, position));
        Fragment item = mFragments.get(position);
        if (instantiateItem == item) {
            return instantiateItem;
        } else {
            //如果集合中对应下标的fragment和fragmentManager中的对应下标的fragment对象不一致，那么就是新添加的，所以自己add进入；这里为什么不直接调用super方法呢，因为fragment的mIndex搞的鬼，以后有机会再补一补。
            mFragmentManager.beginTransaction().add(container.getId(), item).commitNowAllowingStateLoss();
            return item;
        }
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        Fragment fragment = (Fragment) object;
        //如果getItemPosition中的值为PagerAdapter.POSITION_NONE，就执行该方法。
        if (mFragments.contains(fragment)) {
            super.destroyItem(container, position, fragment);
            return;
        }
        //自己执行移除。因为mFragments在删除的时候就把某个fragment对象移除了，所以一般都得自己移除在fragmentManager中的该对象。
        mFragmentManager.beginTransaction().remove(fragment).commitNowAllowingStateLoss();
    }


    public void removeOther(int position) {
        List<Fragment> fgs=new ArrayList<>();
        for (Fragment fg:mFragments) {
            if (fg != mFragments.get(position)) {
                fgs.add(fg);
            }
        }
        mFragments.removeAll(fgs);
        notifyDataSetChanged();
    }


    public void remove(int position) {
        mFragments.remove(position);
        notifyDataSetChanged();
    }

    public void clear() {
        mFragments.clear();
        notifyDataSetChanged();
    }

    public void addData(Fragment fragment) {
        mFragments.add(fragment);
        notifyDataSetChanged();
    }


    public void setData(List<Fragment> fragments){
        mFragments.clear();
        mFragments.addAll(fragments);
        notifyDataSetChanged();
    }
    
}