DashboardActivity.java

package com.codewithharry.firebase;

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.MenuItem;

import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentTransaction;

import com.codewithharry.firebase.notifications.Token;
import com.google.android.gms.tasks.Task;
import com.google.android.material.bottomnavigation.BottomNavigationView;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.iid.internal.FirebaseInstanceIdInternal;
import com.google.firebase.installations.FirebaseInstallations;
import com.google.firebase.installations.InstallationTokenResult;

public class DashboardActivity extends AppCompatActivity {

    //FireBase aUth
    FirebaseAuth firebaseAuth;

    ActionBar actionBar;
    String mUID;

    private final BottomNavigationView.OnNavigationItemSelectedListener selectedListener =
            new BottomNavigationView.OnNavigationItemSelectedListener() {
                @Override
                public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
                    //handle item clicks
                    switch (menuItem.getItemId()) {
                        case R.id.nav_home:
                            //home fragment transaction
                            actionBar.setTitle("Home");//change actionBar title
                            HomeFragment fragment1 = new HomeFragment();
                            FragmentTransaction ft1 = getSupportFragmentManager().beginTransaction();
                            ft1.replace(R.id.content, fragment1, "");
                            ft1.commit();
                            return true;
                        case R.id.nav_profile:
                            //profile fragment transaction
                            actionBar.setTitle("Profile");//change actionBar title
                            ProfileFragment fragment2 = new ProfileFragment();
                            FragmentTransaction ft2 = getSupportFragmentManager().beginTransaction();
                            ft2.replace(R.id.content, fragment2, "");
                            ft2.commit();
                            return true;
                        case R.id.nav_users:
                            //users fragment transaction
                            actionBar.setTitle("Users");//change actionBar title
                            UsersFragment fragment3 = new UsersFragment();
                            FragmentTransaction ft3 = getSupportFragmentManager().beginTransaction();
                            ft3.replace(R.id.content, fragment3, "");
                            ft3.commit();
                            return true;
                        case R.id.nav_chat:
                            //users fragment transaction
                            actionBar.setTitle("Chats");//change actionBar title
                            ChatListFragment fragment4 = new ChatListFragment();
                            FragmentTransaction ft4 = getSupportFragmentManager().beginTransaction();
                            ft4.replace(R.id.content, fragment4, "");
                            ft4.commit();
                            return true;
                    }
                    return false;
                }
            };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_dashboard);


        //ActionBar and its title
        actionBar = getSupportActionBar();
        assert actionBar != null;
        actionBar.setTitle("Profile");

        //init
        firebaseAuth = FirebaseAuth.getInstance();
        //Init views
        //Bottom Navigation
        BottomNavigationView navigationView = findViewById(R.id.navigation);
        navigationView.setOnNavigationItemSelectedListener(selectedListener);

        //Home fragment transaction(default, on start)
        actionBar.setTitle("Home");//change actionBar title
        HomeFragment fragment1 = new HomeFragment();
        FragmentTransaction ft1 = getSupportFragmentManager().beginTransaction();
        ft1.replace(R.id.content, fragment1, "");
        ft1.commit();

        checkUserStatus();

    }

    @Override
    protected void onResume() {
        checkUserStatus();
        super.onResume();
    }

    public void updateToken(Task<InstallationTokenResult> token) {
        DatabaseReference ref = FirebaseDatabase.getInstance().getReference("Tokens");
        Token mToken = new Token(token);
        ref.child(mUID).setValue(mToken);
    }

    private void checkUserStatus() {
        //Get current user
        FirebaseUser user = firebaseAuth.getCurrentUser();
        if (user != null) {
            //User is signed in stay here
            //set email of logged in user
            //mProfileTv.setText(user.getEmail());
            mUID = user.getUid();

            SharedPreferences sp = getSharedPreferences("SP_USER", MODE_PRIVATE);
            SharedPreferences.Editor editor = sp.edit();
            editor.putString("Current_USERID", mUID);
            editor.apply();

            //update token
            updateToken(FirebaseInstallations.getInstance().getToken(true));

        } else {
            //User not signed in go to main activity
            startActivity(new Intent(DashboardActivity.this, MainActivity.class));
            finish();
        }
    }

    @Override
    public void onBackPressed() {
        super.onBackPressed();
        finish();
    }

    @Override
    protected void onStart() {
        //check on start of app
        checkUserStatus();
        super.onStart();
    }

}