滑动至刷新需要滑动两次以清楚地更新数据

Question

我有viewpager和tablayout，并且其中有3个fragment。在我的fragment 2和3中，我滑动以刷新以更新Firebase数据库中的数据。

  

问题

     

我必须刷两次刷新，然后才更新。但是，如果我滑动1次，则什么也不会发生。另一种情况是，我滑动tablayout 1次，然后回到要刷新的fragment，然后更新了。

TwoFragment

@Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);

        if (isVisibleToUser) {

        } else {
            mAuth = FirebaseAuth.getInstance();
            userRef = FirebaseDatabase.getInstance().getReference("user_course");
            users = FirebaseAuth.getInstance().getCurrentUser();
            daftarTugasRef = FirebaseDatabase.getInstance().getReference("tugas");
            mTugasRef = FirebaseDatabase.getInstance().getReference("tugas_course");
            mFlagTugas = FirebaseDatabase.getInstance().getReference("flag_tugas");

            LoadData();
        }
    }


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    setHasOptionsMenu(true);

    v =  inflater.inflate(R.layout.fragment_two, container, false);

swipeLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                new Handler().postDelayed(new Runnable() {

                    @Override public void run() {
                        LoadData();
                        swipeLayout.setRefreshing(false);
                        listTugas.clear();

                    }
                    private void onLoaded() {
                        swipeLayout.setEnabled(true);
                        swipeLayout.setRefreshing(false);
                    }

                }, 500);
            }
        });

MainActivity

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

       viewPager = (ViewPager) findViewById(R.id.viewpager);
        viewPager.setOffscreenPageLimit(3);
        setupViewPager(viewPager);
        viewPager.setCurrentItem(position);
        tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(viewPager);


        setupTabIcons();
}

private void setupViewPager(ViewPager viewPager) {
        adapter = new ViewPagerAdapter(getSupportFragmentManager());
        adapter.addFrag(new OneFragment(), "ONE");
        adapter.addFrag(new TwoFragment(), "TWO");
        adapter.addFrag(new ThreeFragment(), "THREE");
        viewPager.setAdapter(adapter);
        viewPager.getAdapter().notifyDataSetChanged();
    }




    class ViewPagerAdapter extends FragmentStatePagerAdapter {
        private final List<Fragment> mFragmentList = new ArrayList<>();
        private final List<String> mFragmentTitleList = new ArrayList<>();

        public ViewPagerAdapter(FragmentManager manager) {
            super(manager);
        }

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

        @Override
        public int getCount() {
            return mFragmentList.size();
        }



        public void addFrag(Fragment fragment, String title) {
            mFragmentList.add(fragment);
            mFragmentTitleList.add(title);
        }

        @Override
        public int getItemPosition(@NonNull Object object) {
            return POSITION_NONE;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return mFragmentTitleList.get(position);
        }
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

    }




    @Override
    public void onPageSelected(int position) {
//        viewPager.getAdapter().notifyDataSetChanged();

//        adapter.notifyDataSetChanged();
    }

    @Override
    public void onPageScrollStateChanged(int state) {

    }