fragment中嵌套viewpager的问题

[bigggge]

我的主activity包含两个fragment，他们是由replaceFragmentWithSelected方法进行切换的

  protected void replaceFragmentWithSelected(Fragment fragment) {

        FragmentTransaction fragmentTransaction = this
                .getSupportFragmentManager().beginTransaction();
        fragmentTransaction.replace(R.id.frame_content, fragment);
        fragmentTransaction.commit();

    }

这两个fragment都有各自的viewpager

 
public class CommunityFragment extends BaseFragment {
    private CommonTitleBar titleBar;
    private View view;
    private PagerSlidingTabStrip tabs;
    private ViewPager pager;
    private CommunicatePagerAdapter adapter;
    private ArrayList<Fragment> fragmentList;
    private Communication communication;
    private QuanZi quanZi;
    private Story story;
    private final String[] titles = {"交流", "圈子", "故事"};
    SicknessChangedReceiver sicknessChangedReceiver;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        sicknessChangedReceiver = new SicknessChangedReceiver();
        IntentFilter intentFilter = new IntentFilter("xp.yhx.com");
        getActivity().registerReceiver(sicknessChangedReceiver, intentFilter);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        if (view == null) {
            view = inflater.inflate(R.layout.fragment_community, null);
            initViews();
            initPager();
        }
        ViewGroup parent = (ViewGroup) view.getParent();
        if (parent != null) {
            parent.removeView(view);
        }
//        replaceFragmentWithSelected(communication);
        return view;
    }

    public void onDetach() {
        super.onDetach();
        try {
            Field childFragmentManager = Fragment.class.getDeclaredField("mChildFragmentManager");
            childFragmentManager.setAccessible(true);
            childFragmentManager.set(this, null);
        } catch (NoSuchFieldException e) {
            throw new RuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        getActivity().unregisterReceiver(sicknessChangedReceiver);
    }


    private void initViews() {
        communication = Communication.newInstance("2");
        quanZi = QuanZi.newInstance("2");
        story = Story.newInstance("2");
        fragmentList = new ArrayList<>();
        fragmentList.add(communication);
        fragmentList.add(quanZi);
        fragmentList.add(story);

        tabs = (PagerSlidingTabStrip) view.findViewById(R.id.tabs);
        titleBar = (CommonTitleBar) view.findViewById(R.id.title_layout);
        titleBar.setLeftButtonColorDefault();
        titleBar.setRightButtonColorDefault();
        titleBar.setLeftBtnOnclickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getActivity(), MultiTagActivity.class);
                intent.putExtra("isFromCom", true);
                intent.putExtra("tag", 1);
                startActivity(intent);
            }
        });
        titleBar.setRightBtnOnclickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (TextUtils.isEmpty(SPUtils.getInstance(getActivity()).getValue("id"))) {
                    new MaterialDialog.Builder(getActivity())
                            .content("请先登录你的账号")
                            .positiveText("登录")
                            .negativeText("返回")
                            .cancelable(false)
                            .callback(new MaterialDialog.ButtonCallback() {
                                          @Override
                                          public void onPositive(MaterialDialog dialog) {
                                              Intent intent = new Intent(getActivity(), LoginActivity.class);
                                              startActivity(intent);
                                          }
                                      }
                            ).show();
                } else {
                    initDialog();
                }
            }
        });
    }

    private void initPager() {
        pager = (ViewPager) view.findViewById(R.id.pager);
        adapter = new CommunicatePagerAdapter(titles, getChildFragmentManager(), fragmentList);
        pager.setAdapter(adapter);
        pager.setOffscreenPageLimit(3);
        tabs.setViewPager(pager);
    }

    private void initDialog() {
        new MaterialDialog.Builder(getActivity())
                .items(new String[]{"发起我的交流", "分享我的故事"})
                .itemsCallback(new MaterialDialog.ListCallback() {
                    @Override
                    public void onSelection(MaterialDialog dialog, View view, int which, CharSequence text) {
                        if (which == 0) { //交流
                            startActivityForResult(new Intent(getActivity(), StartStoryActivity.class).putExtra("type", 1), 1);
                        } else if (which == 1) {//故事
                            startActivityForResult(new Intent(getActivity(), StartStoryActivity.class).putExtra("type", 3), 3);
                        }
                    }
                })
                .show();
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (resultCode) {
            case 2003:
                pager.setCurrentItem(2, false);
                break;
            case 2001:
                pager.setCurrentItem(0, false);
                break;
        }
    }

这是adapter

public class CommunicatePagerAdapter extends FragmentPagerAdapter{
    String[] titles;
    List<Fragment> lists;
    FragmentManager fm;

    public CommunicatePagerAdapter(String[] titles, FragmentManager fm, List<Fragment> lists) {
        super(fm);
        this.fm = fm;
        this.titles = titles;
        this.lists = lists;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return titles[position];
    }

    @Override
    public int getCount() {
        return 3;
    }

    @Override
    public Fragment getItem(int arg0) {
//        Fragment fragment;
//        switch (arg0) {
//            case 0:
//                return Communication.newInstance("2");
//            case 1:
//                return QuanZi.newInstance("2");
//
//            default:
//                return Story.newInstance("2");
//
//        }
        return lists.get(arg0);
    }

    @Override
    public void destroyItem(android.view.ViewGroup aContainer, int aPosition, java.lang.Object aObject) {
        if (aPosition <= getCount() && aObject != null) {
            FragmentTransaction trans = fm.beginTransaction();
            trans.remove((Fragment) aObject);
            trans.commit();
        }
    }

}

当我第一次进入主activity的两个fragment时，他们的子fragment都能正常显示，但第二次就不行了，报pager空指针，然后我尝试在onCreateView方法中view！=null时initPager();，报activity has been destroyed 错误，我应该怎么改，才能使两个fragment中的两个viewpager都生效？谢谢