Question

我正在设计一个应用，该应用在homeActivity上具有4个不同的片段，并使用bottomNavigation在它们之间进行切换；在我用作新闻供稿的首页上，这些项目不会显示，直到我切换到另一个片段，然后再次回来。我了解在SO上存在与此类似的问题，但就我而言似乎没有解决方案。我认为问题与片段中onCreate（）和onCreateView的差异有关。

感谢您的帮助。

public class HomeFragment extends Fragment {

View v;
private RecyclerView recyclerView;
private List<Drink> drinksList;
RecyclerViewAdapter recyclerViewAdapter;

public HomeFragment() {
    // Required empty public constructor
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    v =  inflater.inflate(R.layout.fragment_home, container, false);


    return v;
}

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    drinksList = new ArrayList<>();
    drinksList.add(new Drink("Latte",999,"Coffee","test",1.99,77,R.drawable.latte));
    drinksList.add(new Drink("Black Tea",123,"Tea", "test", 1.50,11,R.drawable.blacktea));

}

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);

    recyclerView = v.findViewById(R.id.recyclerView);
    recyclerViewAdapter = new RecyclerViewAdapter(drinksList,getContext());
    recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
    recyclerView.setAdapter(recyclerViewAdapter);
    recyclerViewAdapter.notifyDataSetChanged();
}

}

编辑添加HomeActivity

public void setUpMenuNav（）{

    mMainFrame = findViewById(R.id.mainFrame);
    bottomNavigationView = findViewById(R.id.bottomNaviationView);

    homeFragment = new HomeFragment();
    socialFragment = new SocialFragment();
    trackingFragment = new TrackingFragment();
    locationFragment = new LocationFragment();

    bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            switch (item.getItemId()) {

                case R.id.navHome:
                    setFragment(homeFragment);
                    return true;
                case R.id.navSocial:
                    setFragment(socialFragment);
                    return true;
                case R.id.navTracking:
                    setFragment(trackingFragment);
                    return true;
                case R.id.navLocation:
                    setFragment(locationFragment);
                    return true;
                default:
                    return false;
            }
        }
    });

}


    private void setFragment(Fragment fragment) {

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

}

然后在onCreate（）方法中调用setUpMenuBar

Answer 1

在您的onCreate()的{{1}}方法上

添加HomeActivity。应该可以解决问题的。

在片段之间切换之前，RecyclerView不会显示项目

1 个答案: