AdminManage.java

package com.example.padel;

import android.os.Bundle;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.CalendarView;
import android.widget.QuickContactBadge;
import android.widget.Toast;

import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

import java.util.ArrayList;
import java.util.Date;


public class AdminManage extends Fragment {

    FragmentManager fragmentManager;
    String field;

    private String stringDateSelected;

    ArrayList<String> items_hours, items_coaches;


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


    public static AdminManage newInstance(String param1, String param2) {
        AdminManage fragment = new AdminManage();
        Bundle args = new Bundle();
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        fragmentManager = getParentFragmentManager();
        items_coaches = new ArrayList<String>();
        Bundle data = this.getArguments();
        if(data != null){

            field = data.getString("field");
            System.out.println(field);
        }else{
            System.out.println("data null");
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment

        View view = inflater.inflate(R.layout.fragment_admin_manage, container, false);
        CalendarView calendarView = (CalendarView) view.findViewById(R.id.calendarView);
        Button button = (Button)view.findViewById(R.id.insertLesson);

        DatabaseReference database = FirebaseDatabase.getInstance("https://padel-5d8f6-default-rtdb.europe-west1.firebasedatabase.app").getReference("reservations/"+field);

        DatabaseReference database2 = FirebaseDatabase.getInstance("https://padel-5d8f6-default-rtdb.europe-west1.firebasedatabase.app").getReference("coaches");


        //mi prendo tutti i maestri disponibili
        database2.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot) {

                for (DataSnapshot dataSnapshot : snapshot.getChildren()){

                    Coach coach = dataSnapshot.getValue(Coach.class);
                    items_coaches.add(dataSnapshot.getKey());

                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        });


        //mi prendo orari disponibili su quel campo per quel giorno per poi passarli al fragment
        calendarView.setOnDateChangeListener(new CalendarView.OnDateChangeListener() {
            @Override
            public void onSelectedDayChange(@NonNull CalendarView view, int year, int month, int dayOfMonth) {
                String[] aux_items = new String[]{"09 10", "10 11", "11 12", "12 13", "13 14", "14 15", "15 16", "16 17", "17 18", "18 19", "19 20", "20 21", "21 22", "22 23", "23 24"};
                stringDateSelected = Integer.toString(dayOfMonth) + ":" + Integer.toString(month + 1) + ":" + Integer.toString(year);

                items_hours = new ArrayList<String>(); //simensione massima

                int length = 15;
                String prenotazione = stringDateSelected;

                if(stringDateSelected != null){

                    String[] date_information = stringDateSelected.split(":");
                    //-1900 perchè ritorna a partire dal 1900
                    Date date_selected = new Date(Integer.parseInt(date_information[2])-1900,Integer.parseInt(date_information[1])-1,Integer.parseInt(date_information[0]),23,59);

                    //se selezionata data futura vedo posti disponibili
                    if (date_selected.after(new Date())) {

                        database.addListenerForSingleValueEvent(new ValueEventListener() {
                            @Override
                            public void onDataChange(DataSnapshot snapshot) {

                                //faccio qiery al database per vedere orari disponibili per quel giorno
                                for (int i = 0; i < length; i++) {
                                    if (snapshot.hasChild(prenotazione + "/" + aux_items[i])) {
                                        //nothing
                                    } else {
                                        //System.out.println("Impossbile prenotare");
                                        items_hours.add(aux_items[i]);
                                    }
                                }
                            }

                            @Override
                            public void onCancelled(@NonNull DatabaseError error) {

                            }
                        });
                    }
                }
            }
        });

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                if (stringDateSelected != null) {

                    String[] date_information = stringDateSelected.split(":");
                    //-1900 perchè ritorna a partire dal 1900
                    Date date_selected = new Date(Integer.parseInt(date_information[2]) - 1900, Integer.parseInt(date_information[1]) - 1, Integer.parseInt(date_information[0]),23,59);
                    if (date_selected.before(new Date())) {
                        Toast.makeText(getContext(), "Data selezionata errata", Toast.LENGTH_LONG).show();
                    } else {
                        Bundle data = new Bundle();
                        data.putStringArrayList("items", items_hours);
                        data.putStringArrayList("items_coaches", items_coaches);
                        data.putString("stringDateSelected", stringDateSelected);
                        data.putString("field", field);


                        InsertLessonFragment fragment = new InsertLessonFragment();
                        fragment.setArguments(data);

                        fragmentManager.beginTransaction().replace(R.id.fragmentContainerView, fragment, null)   //vogliamo indicare di spaostarci da questo fragment ad un altro, cambia quello che è in questo containetr con un nuovo fragment
                                .setReorderingAllowed(true)  //reordering allowed
                                .addToBackStack("name") // così che se faccio indietro ritorna a questo fragment
                                .commit();
                    }
                }else{
                    Toast.makeText(getContext(), "Seleziona una data", Toast.LENGTH_LONG).show();
                }
            }
        });
        return view;
    }


}