package com.example.sharma.digimenu.ViewHolder;

import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.sharma.digimenu.Interface.ItemClickListener;
import com.example.sharma.digimenu.R;

public class MenuViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{

    public TextView txtMenuName;
    public ImageView imageView;

    private ItemClickListener itemClickListener;

    public MenuViewHolder(View itemView) {

        super(itemView);
        txtMenuName = itemView.findViewById(R.id.menu_name);
         imageView = itemView.findViewById(R.id.menu_image);
        itemView.setOnClickListener(this);
    }
    public void setItemClickListener(ItemClickListener itemClickListener){
        this.itemClickListener = itemClickListener;
    }
    @Override
    public void onClick (View view) {
        itemClickListener.onClick(view,getAdapterPosition(),false);
    }
}

public class Home extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    FirebaseRecyclerAdapter adapter;
    FirebaseDatabase database;
    DatabaseReference category;

    TextView txtFullName;

    RecyclerView recycler_menu;
    RecyclerView.LayoutManager layoutManager;
    private Picasso.Builder mRecyclerMenu;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);
        Toolbar toolbar = findViewById(R.id.toolbar);
        toolbar.setTitle("Menu");
        setSupportActionBar(toolbar);

        database = FirebaseDatabase.getInstance();
        category = database.getReference("Category");
        FloatingActionButton fab = findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        DrawerLayout drawer = findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

        View headerview  = navigationView.getHeaderView(0);
        txtFullName = headerview.findViewById(R.id.txtFullName);
        txtFullName = (TextView)findViewById(R.id.txtFullName);

        recycler_menu =(RecyclerView) findViewById(R.id.recyclermenu);

        layoutManager = new LinearLayoutManager(this);
        recycler_menu.setLayoutManager(layoutManager);

        loadMenu();
    }

    private void loadMenu(){

        FirebaseRecyclerAdapter<Category,MenuViewHolder> adapter = new FirebaseRecyclerAdapter<Category,
                MenuViewHolder>(Category.class,R.layout.menu_item,MenuViewHolder.class,category) {
            @Override
            protected void populateViewHolder(MenuViewHolder viewHolder, Category model, int position) {
                viewHolder.txtMenuName.setText(model.getName());
                Picasso.with(getBaseContext()).load(model.getImage()).into(viewHolder.imageView);
                final Category clickItem = model;
                viewHolder.setItemClickListener(new ItemClickListener() {
                    @Override
                    public void onClick(View view, int position, boolean isLongClick) {
                        Toast.makeText(Home.this, "" + clickItem.getName(), Toast.LENGTH_SHORT).show();
                    }
                });
            }
        };
    }
    @Override
    public void onBackPressed() {
        DrawerLayout drawer = findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.home, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        return super.onOptionsItemSelected(item);
    }
    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();
        if (id == R.id.nav_menu) {// Handle the camera action
        }
        else if(id == R.id.nav_cart){
        }
        else if(id == R.id.nav_orders){
        }
        else if(id == R.id.nav_logout){
        }

        DrawerLayout drawer = findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }
}

auth.createUserWithEmailAndPassword(edtEmail.getText().toString(), edtPassword.getText().toString())
                        .addOnSuccessListener(new OnSuccessListener<AuthResult>() {
                            @Override
                            public void onSuccess(AuthResult authResult) {
                                User user = new User();
                                user.setEmail(edtEmail.getText().toString());
                                user.setPassword(edtPassword.getText().toString());
                                user.setPhone(edtPhone.getText().toString());
                                user.setName(edtName.getText().toString());
                                users.child(Objects.requireNonNull(FirebaseAuth.getInstance().getCurrentUser()).getUid()).setValue(user)
                                        .addOnSuccessListener(new OnSuccessListener<Void>() {
                                            @Override
                                            public void onSuccess(Void aVoid) {
                                                Snackbar.make(rootLayout, "Register Successfully", Snackbar.LENGTH_SHORT)
                                                        .show();
                                            }
                                        })
                                        .addOnFailureListener(new OnFailureListener() {
                                            @Override
                                            public void onFailure(@NonNull Exception e) {
                                                Snackbar.make(rootLayout, "Failed" + e.getMessage(), Snackbar.LENGTH_SHORT)
                                                        .show();
                                            }
                                        })
                        .addOnFailureListener(new OnFailureListener() {
                            @Override
                            public void onFailure(@NonNull Exception e) {
                                Snackbar.make(rootLayout, "Failed" + e.getMessage(), Snackbar.LENGTH_SHORT)
                                        .show();
                            }
                        });
            }
        });

    }
});
        dialog.setNegativeButton("CANCEL", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {

                dialogInterface.dismiss();
            }
        });
        dialog.show();
    }
    private void showSignInDialog() {

        final AlertDialog.Builder dialog = new AlertDialog.Builder(this);
        dialog.setTitle("SIGN IN");
        dialog.setMessage("Please use email to sign in");

        LayoutInflater inflater = LayoutInflater.from(this);
        View signin_layout = inflater.inflate(R.layout.layout_signin, null);

        final MaterialEditText edtEmail = signin_layout.findViewById(R.id.edtEmail);
        final MaterialEditText edtPassword = signin_layout.findViewById(R.id.edtPassword);

        dialog.setView(signin_layout);

        dialog.setPositiveButton("SIGN IN", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {

                dialogInterface.dismiss();

                if (TextUtils.isEmpty(edtEmail.getText().toString())) {
                    Snackbar.make(rootLayout, "Please enter email address", Snackbar.LENGTH_SHORT).show();
                    return;
                }
                if (TextUtils.isEmpty(edtPassword.getText().toString())) {
                    Snackbar.make(rootLayout, "Please enter  password", Snackbar.LENGTH_SHORT).show();
                    return;
                }
                if (edtPassword.getText().toString().length() < 6) {
                    Snackbar.make(rootLayout, "Password too short!!!", Snackbar.LENGTH_SHORT).show();
                    return;
                }
        auth.signInWithEmailAndPassword(edtEmail.getText().toString(), edtPassword.getText().toString())
                .addOnSuccessListener(new OnSuccessListener<AuthResult>() {
                    public User user;

                    @Override
                    public void onSuccess(AuthResult authResult) {
                        startActivity(new Intent(MainActivity.this, Home.class));
                        Common.currentUser = user;
                        finish();
                    }
                })
                .addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                Snackbar.make(rootLayout, "Failed" + e.getMessage(), Snackbar.LENGTH_SHORT).show();
            }
        });
    }
});
        dialog.setNegativeButton("CANCEL", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                dialogInterface.dismiss();
            }
        });
        dialog.show();
    }
}

[project folder][3]