MainActivity.java

package com.druve.druve;

import android.os.Bundle;


import androidx.annotation.NonNull;
import androidx.core.view.GravityCompat;
import androidx.appcompat.app.ActionBarDrawerToggle;

import android.util.Log;
import android.view.MenuItem;

import com.google.android.material.navigation.NavigationView;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
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 androidx.drawerlayout.widget.DrawerLayout;

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;

import android.view.Menu;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    private static final String TAG = "Activity";
    TextView navNameText, navEmailText, rough;
    ImageView navProfileImage;

    private FirebaseDatabase mFirebaseDatabase;
    private FirebaseAuth mAuth;
    private FirebaseAuth.AuthStateListener mAuthStateListener;
    private DatabaseReference mDatabaseReference;
    private String userId;

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

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

        initViews();
        mAuth = FirebaseAuth.getInstance();
        mFirebaseDatabase = FirebaseDatabase.getInstance();
        mDatabaseReference = mFirebaseDatabase.getReference();
        FirebaseUser user = mAuth.getCurrentUser();
        userId = user.getUid();

        mAuthStateListener = new FirebaseAuth.AuthStateListener() {
            @Override
            public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
                FirebaseUser user = firebaseAuth.getCurrentUser();
                if (user != null) {
                    Toast.makeText(MainActivity.this, "Successfully sign in with" + user.getUid(), Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(MainActivity.this, "Signed out", Toast.LENGTH_SHORT).show();
                }
            }
        };

        mDatabaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                showData(dataSnapshot);
            }

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

            }
        });
    }

    private void showData(DataSnapshot dataSnapshot) {
        Log.d(TAG, "showData: called");
        for (DataSnapshot ds : dataSnapshot.getChildren()) {
            User user = new User();
            user.setName(ds.child(userId).getValue(User.class).getName());
            user.setEmail(ds.child(userId).getValue(User.class).getEmail());
            navNameText.setText(user.getName());
            navEmailText.setText(user.getEmail());
            rough.setText(user.getEmail() + " " + user.getName());

            Log.d(TAG, "showData: " + user.getName());
            Log.d(TAG, "showData: " + user.getEmail());
        }
    }

    @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.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.nav_create_ads) {
            // Handle the camera action
        } else if (id == R.id.nav_crowdvertize) {

        } else if (id == R.id.nav_manage_ads) {

        } else if (id == R.id.nav_balance) {

        } else if (id == R.id.nav_share) {

        } else if (id == R.id.nav_contact) {

        }

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

    public void initViews() {
        navProfileImage = findViewById(R.id.profile_image_nav);
        navEmailText = findViewById(R.id.email_text_nav);
        navNameText = findViewById(R.id.name_text_nav);
        rough = findViewById(R.id.rough);
    }

    @Override
    protected void onStart() {
        super.onStart();
        mAuth.addAuthStateListener(mAuthStateListener);
    }

    @Override
    protected void onStop() {
        super.onStop();
        if (mAuthStateListener != null) {
            mAuth.removeAuthStateListener(mAuthStateListener);
        }
    }
}