viewpager - tabs in android studio example

¿Cómo actualizar recyclerview en la segunda pestaña en viewpager desde la primera pestaña?

Question

Uno de los problemas que estoy enfrentando actualmente es que si un usuario agrega algo a su horario, debe actualizarse en la vista del recyclerview en la segunda pestaña Current Timetable . Sin embargo, nunca se actualiza y el usuario tiene que volver al menú principal, volver a la actividad Timetables y luego seleccionar Current Timetable . Creo que es algo relacionado con mi ViewPager y su adaptador. Simplemente no puedo ver dónde me estoy equivocando y estoy seguro de que es algo simple que me estoy perdiendo. Por favor, podrías modificar mi código para que funcione

Aquí está mi código: La clase viewpager

public class Timetables extends AppCompatActivity{
    TabLayout tabLayout;
    ViewPager viewPager;
    Context context;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.timetables);
        viewPager = (ViewPager) findViewById(R.id.viewPager);
        TimetablesAdapter timetablesAdapter = new TimetablesAdapter(getSupportFragmentManager(), Timetables.this);
        viewPager.setAdapter(timetablesAdapter);
        viewPager.setOffscreenPageLimit(2);
        tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(viewPager);
        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                viewPager.setCurrentItem(tab.getPosition());
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {
                //viewPager.setCurrentItem(tab.getPosition());
            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {
                //viewPager.setCurrentItem(tab.getPosition());
            }
        });
    }
}

La clase fragmentpageradapter:

public class TimestableAdapter extends FragmentPagerAdapter{

    String tabNames[] = new String[] {"All timetables", "Current Timetable", "Expired"};
    Context context;

    public TimestableAdapter(FragmentManager fragmentManager, Context context){
        super(fragmentManager);
        this.context = context;
    }

    @Override
    public Fragment getItem(int position) {
        switch (position){
            case 0:
                return new AllTimetables();
            case 1:
                return new CurrentTimetables();
            case 2:
                return new ExpiredTimetables();
            default:
                return null;
        }
    }

    @Override
    public int getCount() {
        return tabNames.length;
    }

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

Esta es la clase CurrentTimetable :

public class CurrentTimetables extends Fragment {
    RecyclerView recyclerView;
    static MusicRecyclerAdapter adapter;
    RecyclerView.LayoutManager layoutManager;
    ArrayList<Timetables> list;

    public CurrentTimetables(){

    }

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

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.currenttimetable, container, false);
        recyclerView = (RecyclerView) rootView.findViewById(R.id.timetablerecyclerView);
        recyclerView.setHasFixedSize(true);
        list = new ArrayList<Timetables>();
        adapter = new MusicRecyclerAdapter(list, CurrentTimetables.this);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity().getApplicationContext());
        linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(linearLayoutManager);
        recyclerView.setAdapter(adapter);
        tabBackground = new TabBackground(CurrentTimetables.this, list, spinnerItems, adapter, spinnerAdapter);
        tabBackground.populateConditionsList();
        inputs = new ArrayList<>();
        populate();
        return rootView;
    }

    @Override
    public void onResume() {
        super.onResume();
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {

    }

    @Override
    public void onStart() {
        super.onStart();
    }

    public void populate(){
        String dbURL = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
        RequestQueue requestQueue = Volley.newRequestQueue(fragment.getActivity());
        JsonArrayRequest jsonArrayRequest = new JsonArrayRequest
                (dbURL, new Response.Listener<JSONArray>(){

                    @Override
                    public void onResponse(JSONArray jsonArray) {
                        if(!list.isEmpty()){
                            list.clear();
                        }
                        try {
                            for (int i = 0; i < jsonArray.length(); i++) {
                                JSONObject jsonObject = jsonArray.getJSONObject(i);

                                int timetableID = Integer.parseInt(jsonObject.getString("timetableID"));
                                String timetableName = jsonObject.getString("timetableName");
                                String subjectName = jsonObject.getString("subjectName");

                                Timetables timetables = new Timetables(timetableID, timetableName, subjectName);
                                list.add(timetables);
                                adapter.notifyDataSetChanged();
                            }
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                }, new Response.ErrorListener(){

                    @Override
                    public void onErrorResponse(VolleyError volleyError) {

                    }
                }
                );
        requestQueue.add(jsonArrayRequest);
    }
 }

Realmente significaría que mucha gente podría ayudarme

Gracias

Answer 1

Hay algunos cambios necesarios en su código. Si revisas Fragment''s LifeCycle , entenderás cómo funciona con Tabular View.

Echa un vistazo al Código que he hecho desde el código anterior.

public class CurrentTimetables extends Fragment {
    RecyclerView recyclerView;
    static MusicRecyclerAdapter adapter;
    RecyclerView.LayoutManager layoutManager;
    ArrayList<Timetables> list;
    Context context;

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        this.context = context;
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.currenttimetable, container, false);
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        recyclerView = (RecyclerView) view.findViewById(R.id.timetablerecyclerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(context));
        tabBackground = new TabBackground(CurrentTimetables.this, list, spinnerItems, adapter, spinnerAdapter);
        tabBackground.populateConditionsList();
        // If you have another Component add here using finViewById() and also you can do
        // other process here. I just used setUserVisibleHint because it will execute when
        // fragment will be visible to user and it will stop over calling to web service.
        /**
         * Populate Recyclerview data if setUserVisibleHint do not work.
         */
    }

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

    public void populate() {
        String dbURL = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
        RequestQueue requestQueue = Volley.newRequestQueue(context);
        JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(dbURL, new Response.Listener<JSONArray>() {

            @Override
            public void onResponse(JSONArray jsonArray) {
                if (!list.isEmpty()) {
                    list.clear();
                }
                try {
                    list = new ArrayList<Timetables>();
                    for (int i = 0; i < jsonArray.length(); i++) {
                        JSONObject jsonObject = jsonArray.getJSONObject(i);

                        int timetableID = Integer.parseInt(jsonObject.getString("timetableID"));
                        String timetableName = jsonObject.getString("timetableName");
                        String subjectName = jsonObject.getString("subjectName");

                        Timetables timetables = new Timetables(timetableID, timetableName, subjectName);
                        list.add(timetables);
                        adapter = new MusicRecyclerAdapter(list, context);
                        recyclerView.setAdapter(adapter);
                        adapter.notifyDataSetChanged();
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }, new Response.ErrorListener() {

            @Override
            public void onErrorResponse(VolleyError volleyError) {

            }
        });
        jsonArrayRequest.setRetryPolicy(new DefaultRetryPolicy(5 * 1000, 1, 1.0F));
        jsonArrayRequest.setShouldCache(false);
        requestQueue.add(jsonArrayRequest);
    }

    @Override
    public void onResume() {
        super.onResume();
        populate();
    }
}

Es posible que haya olvidado algo de su código y que tenga que agregarlo.

Answer 2

Tienes que crear una interfaz en mainActivity. Refiéralo en tus fragmentos. Es la mejor manera de comunicarse de un fragmento a otro. Por favor, consulte el siguiente enlace.

http://developer.android.com/training/basics/fragments/communicating.html

Eche un vistazo y si tiene alguna duda aquí para ayudar.