Android Studio – java.lang.IllegalStateException: Default FirebaseApp is not initialized in this process. Make sure to call FirebaseApp.initializeApp(Context) first

I’m having a problem with the app created, I looked for many solutions and none of them work. Neither putting the code that tells me, nor updating everything… It says it’s something related to Firebase, but I don’t know how to solve it, here is my error and code.

 Process: com.paradigma.SIGEPedidos, PID: 14396
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.paradigma.SIGEPedidos/com.paradigma.SIGEPedidos.views.StartActivity}: java.lang.IllegalStateException: Default FirebaseApp is not initialized in this process com.paradigma.SIGEPedidos. Make sure to call FirebaseApp.initializeApp(Context) first.
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3835)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4011)
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2325)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loop(Looper.java:246)
    at android.app.ActivityThread.main(ActivityThread.java:8633)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)
 Caused by: java.lang.IllegalStateException: Default FirebaseApp is not initialized in this process com.paradigma.SIGEPedidos. Make sure to call FirebaseApp.initializeApp(Context) first.
    at com.google.firebase.FirebaseApp.getInstance(FirebaseApp.java:184)
    at com.google.firebase.iid.FirebaseInstanceId.getInstance(com.google.firebase:firebase-iid@@20.1.6:1)
    at com.paradigma.SIGEPedidos.views.StartActivity.refreshTokenDevice(StartActivity.java:41)
    at com.paradigma.SIGEPedidos.views.StartActivity.onCreate(StartActivity.java:37)
    at android.app.Activity.performCreate(Activity.java:8207)
    at android.app.Activity.performCreate(Activity.java:8191)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3808)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4011) 
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85) 
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2325) 
    at android.os.Handler.dispatchMessage(Handler.java:106) 
    at android.os.Looper.loop(Looper.java:246) 
    at android.app.ActivityThread.main(ActivityThread.java:8633) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130) 

Build Grade (app):

    plugins{
    id 'com.android.application'
    id 'com.google.gms.google-services'
}

android {
    compileSdkVersion 31

    defaultConfig {
        applicationId "com.paradigma.SIGEPedidos"
        minSdkVersion 19
        targetSdkVersion 31
        versionCode 20
        versionName "1.20.0-alpha"
        multiDexEnabled true

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        javaCompileOptions {
            annotationProcessorOptions {
                arguments = ["room.schemaLocation": "$projectDir/schemas".toString()]
            }
        }
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
        debug {
            resValue("string", "PORT_NUMBER", "8081")
        }
    }
    compileOptions {
        targetCompatibility = 1.8
        sourceCompatibility = 1.8
    }

}
apply plugin: 'com.google.gms.google-services'
dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])

    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'com.google.android.material:material:1.2.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'androidx.navigation:navigation-fragment:2.3.0'
    implementation 'androidx.navigation:navigation-ui:2.3.0'
    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    implementation project(path: ':EmptyMessageLayout')
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'


    implementation 'com.squareup.retrofit2:retrofit:2.4.0'
    implementation 'com.squareup.retrofit2:converter-gson:2.3.0'
    implementation 'com.squareup.okhttp3:logging-interceptor:3.9.1'

    implementation 'com.android.support:multidex:2.0.1'
    def room_version = "2.2.5"
    implementation "androidx.room:room-runtime:$room_version"
    annotationProcessor "androidx.room:room-compiler:$room_version"

    implementation 'androidx.recyclerview:recyclerview:1.1.0'
    implementation "androidx.cardview:cardview:1.0.0"
    implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
    implementation 'androidx.paging:paging-runtime:2.1.2'
    implementation "androidx.work:work-runtime:2.4.0"


    implementation 'com.google.firebase:firebase-ads:17.0.0'
    implementation 'com.google.firebase:firebase-database:20.0.5'
    implementation 'com.google.firebase:firebase-core:21.0.0'
    implementation 'com.google.firebase:firebase-messaging:20.1.6'
    implementation 'com.google.firebase:firebase-analytics:17.4.0'
    implementation 'com.firebaseui:firebase-ui-auth:3.1.2'
    implementation "com.google.firebase:firebase-perf:19.0.10"

    implementation 'com.github.bumptech.glide:glide:4.9.0'
    annotationProcessor 'com.github.bumptech.glide:compiler:4.9.0'

    debugImplementation 'com.amitshekhar.android:debug-db-encrypt:1.0.6'

    implementation 'com.amulyakhare:com.amulyakhare.textdrawable:1.0.1'
    implementation 'com.google.android:flexbox:2.0.1'

    implementation 'com.paradigma.components:components:1.0.0'

    apply plugin: 'com.google.gms.google-services'
}

Build Grade (Module):

    // Top-level build file where you can add configuration options common to all sub-projects/modules.
Properties properties = new Properties()
properties.load(project.rootProject.file('local.properties').newDataInputStream())

def USERNAME = properties.getProperty('USERNAME')
def PASSWORD = properties.getProperty('PASSWORD')

buildscript {

    repositories {
        google()
        jcenter()
        maven {
            url 'http://dl.bintray.com/amulyakhare/maven'
            allowInsecureProtocol = true
        }
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:7.2.1'
        classpath "com.google.firebase:firebase-plugins:2.0.0"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
        classpath 'com.google.gms:google-services:4.3.10'

    }
}

allprojects {
    repositories {
        google()
        jcenter()
        maven {
            credentials {
                username USERNAME
                password PASSWORD
            }

            authentication {
                basic(BasicAuthentication)
            }

            url "https://api.bitbucket.org/2.0/repositories/" + COMPANY + "/" + REPOSITORY_NAME + "/src/release"
        }
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

Main Activity:

    package com.paradigma.SIGEPedidos.views.main;

import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBarDrawerToggle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;
import androidx.core.view.GravityCompat;
import androidx.drawerlayout.widget.DrawerLayout;

import android.annotation.SuppressLint;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.text.Spannable;
import android.text.SpannableString;
import android.text.style.ForegroundColorSpan;
import android.text.style.TextAppearanceSpan;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;

import com.google.android.material.appbar.AppBarLayout;
import com.google.android.material.dialog.MaterialAlertDialogBuilder;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.paradigma.SIGEPedidos.R;
import com.paradigma.SIGEPedidos.component.searchtoolbar.SearchToolbar;
import com.paradigma.SIGEPedidos.repositories.LoginRepository;
import com.paradigma.SIGEPedidos.utils.PreferencesMethods;
import com.google.android.material.appbar.MaterialToolbar;
import com.google.android.material.navigation.NavigationView;
import com.paradigma.SIGEPedidos.views.login.LoginActivity;
import com.paradigma.SIGEPedidos.views.UpdateActivity;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.AppBarConfiguration;
import androidx.navigation.ui.NavigationUI;

public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {

    DrawerLayout drawer;
    NavigationView navigationView;
    ActionBarDrawerToggle toggle;

    private FloatingActionButton cartFAB;

    MaterialToolbar toolbar;
    private ToolbarHelper toolbarHelper;
    AppBarLayout appBarLayout;
    private CollapsingToolbarHelper collapsingToolbarHelper;
    private SearchViewHelper searchViewHelper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        registerReceiver(RECEIVER_CLOSE, new IntentFilter("close"));
        registerReceiver(RECEIVER_UPDATE, new IntentFilter("update"));
        setContentView(R.layout.activity_articulos);

        toolbar = findViewById(R.id.toolbar);
        toolbarHelper = new ToolbarHelper(this, toolbar);
        setSupportActionBar(toolbar);

        appBarLayout = findViewById(R.id.toolbar_layout);
        collapsingToolbarHelper = new CollapsingToolbarHelper(this, appBarLayout);
        collapsingToolbarHelper.configure();
        collapsingToolbarHelper.getTxtCliente().setOnClickListener(
                v -> goTo(R.id.action_to_listasDePreciosFragment)
            );

        cartFAB = findViewById(R.id.button_ver_pedidos);

        searchViewHelper = new SearchViewHelper(this,appBarLayout);

        initNavigationDrawer();
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
        AppBarConfiguration appBarConfiguration =
                new AppBarConfiguration.Builder(navController.getGraph()).build();
        NavigationUI.setupWithNavController(toolbar, navController, appBarConfiguration);
        SearchToolbar searchToolbar = findViewById(R.id.search_toolbar);
        navController.addOnDestinationChangedListener((controller, destination, arguments) -> {
            if(destination.getId() == R.id.ArticulosFragment){
                collapsingToolbarHelper.setExpanded(true, true);
                cartFAB.setVisibility(View.VISIBLE);
                navigationView.setCheckedItem(R.id.action_articulos);
                drawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
                toggle.syncState();
                toolbarHelper.configureToolbar();
                toolbar.setNavigationOnClickListener(v -> drawer.openDrawer(GravityCompat.START));
            }else{
                if(searchToolbar.isOpen()) searchToolbar.close();
                cartFAB.setVisibility(View.GONE);
                collapsingToolbarHelper.setExpanded(false,true);
                drawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
                toolbar.setNavigationOnClickListener(v -> onBackPressed());
            }
        });
    }

    public CollapsingToolbarHelper getCollapsingToolbarHelper() {
        return collapsingToolbarHelper;
    }

    public SearchViewHelper getSearchViewHelper() {
        return searchViewHelper;
    }

    @Override
    public void onBackPressed() {
        if(drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START); return;
        }
        if(collapsingToolbarHelper.isOpenDrawerLayoutFilter()){
            collapsingToolbarHelper.closeDrawerLayoutFilter(); return;
        }

        NavController navController =
                Navigation.findNavController(this, R.id.nav_host_fragment);

        if( navController.getCurrentDestination().getId() == R.id.ArticulosFragment) {
            showDialogSalir();
        }else{
            super.onBackPressed();
        }
    }

    public void showDialogSalir(){
        SpannableString spanTitle = new SpannableString("Cerrar");
        spanTitle.setSpan(new ForegroundColorSpan(
                        ContextCompat.getColor(this, R.color.colorPrimary)),
                0, spanTitle.length(),
                Spannable.SPAN_EXCLUSIVE_EXCLUSIVE
        );

        String msg = "¿Desea salir de la aplicación?";

        new MaterialAlertDialogBuilder(this)
                .setTitle(spanTitle)
                .setMessage(msg).setPositiveButton(
                "Aceptar", (dialog, which) -> {
                    dialog.dismiss();
                    super.onBackPressed();
                }).setNeutralButton("Cancelar", (dialog, which) -> dialog.dismiss()).show();
    }
    @Override
    @SuppressLint("NonConstantResourceId")
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        int itemId = item.getItemId();
        switch (itemId){
            case R.id.action_create_objeto_facturable:
                goTo(R.id.action_to_CreateObjectoFacturableFragment);break;
            case R.id.action_pendientes:
                goTo(R.id.action_to_pedidosPendientesFragment);break;
            case R.id.action_enviados:
                goTo(R.id.action_to_pedidosApiFragment);break;
            case R.id.action_listaDePrecios:
                goTo(R.id.action_to_listasDePreciosFragment);break;
            case R.id.action_clientes_sin_alta:
                goTo(R.id.action_to_ClientesSinAltaFragment);break;
            case R.id.action_log_out:
                this.logOut();break;
            default:break;
        }
        return false;
    }

    private void logOut() {
        LoginRepository.getInstance().logOut(this);
        Intent intent = new Intent(this, LoginActivity.class);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
        startActivity(intent);
    }

    private void goTo(int fragment){
        Navigation.findNavController(this,R.id.nav_host_fragment).navigate(fragment);
        drawer.closeDrawer(GravityCompat.START);
    }

    public void initNavigationDrawer(){
        drawer = findViewById(R.id.drawer_layout_main);
        navigationView = findViewById(R.id.articulos_nav_view);
        toggle = new ActionBarDrawerToggle(this, drawer, toolbar,
                R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        navigationView.setNavigationItemSelectedListener(this);
        drawer.addDrawerListener(toggle);
        toggle.syncState();

        initMenuStyles(navigationView.getMenu());

        TextView username = navigationView.getHeaderView(0).findViewById(R.id.textview_username);
        String usernameString = PreferencesMethods.getUsername(this) + "!";
        username.setText(usernameString);

        navigationView.setNavigationItemSelectedListener(this);
    }

    private void initMenuStyles(Menu menu) {
        int itemCategoryColor = R.style.item_category_color;
        setStyleCategory(R.id.cuenta_menu_category, itemCategoryColor, menu);
        setStyleCategory(R.id.listas_menu_category, itemCategoryColor, menu);
        setStyleCategory(R.id.pedido_menu_category, itemCategoryColor, menu);
        setStyleCategory(R.id.action_articulos, R.style.item_category_rounded,menu);
    }

    private void setStyleCategory(int category,int style, Menu menu){
        MenuItem tools= menu.findItem(category);
        SpannableString s = new SpannableString(tools.getTitle());
        s.setSpan(new TextAppearanceSpan(this, style), 0, s.length(), 0);
        tools.setTitle(s);
    }

    private final BroadcastReceiver RECEIVER_CLOSE = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String message = "Se ha cerrado la sesión";

            if(intent.getStringExtra("message_close") != null){
                message = intent.getStringExtra("message_close");
            }

            MaterialAlertDialogBuilder messageDialog = new MaterialAlertDialogBuilder(context)
                    .setTitle("Sesión Finalizada")
                    .setMessage(message)
                    .setPositiveButton("Cerrar", (dialog, which) -> dialog.dismiss());
            messageDialog.setOnDismissListener(dialog -> finish());
            messageDialog.show();
        }
    };

    private final BroadcastReceiver RECEIVER_UPDATE = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent){goToUpdateActivity();}
    };

    @Override
    protected void onDestroy() {
        try{
        unregisterReceiver(RECEIVER_UPDATE);
        }catch (Exception ignored){}
        unregisterReceiver(RECEIVER_CLOSE);
        super.onDestroy();
    }

    @Override
    protected void onPause() {
        unregisterReceiver(RECEIVER_UPDATE);
        super.onPause();
    }

    @Override
    protected void onResume(){
        super.onResume();
        registerReceiver(RECEIVER_UPDATE, new IntentFilter("update"));
    }

    private void goToUpdateActivity(){
        Intent intent = new Intent (this, UpdateActivity.class);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
        this.finishAffinity();
        startActivity(intent);
    }
}

I hope you can fix the error so I can run it, because every time I try it crashes instantly. If you need any more code, let me know! Thank you. Previously I had another error but I was able to fix it, and because of that it generated this new one.