A Complete Guide - Android Firebase Integration Auth, Firestore, Cloud Messaging

Prerequisites

1. Android Studio: Make sure you have the latest version of Android Studio installed.
2. Firebase Account: You need a Firebase account and a project set up in the Firebase Console.

Step 1: Create a New Android Project

1. Open Android Studio and select "New Project".
2. Choose "Empty Activity" and click "Next".
3. Configure your project:
   • Name: FirebaseIntegration
   • Package name: com.example.firebaseintegration
   • Save location: Choose a directory.
   • Language: Java/Kotlin (This guide will use Java).
   • Minimum API level: Choose an appropriate level.
4. Click "Finish" to create the project.

Step 2: Set Up Firebase Project

1. Go to the Firebase Console (
2. Click on "Add Project" and follow the prompts to create a new Firebase project.
3. Once the project is created, click on "Android" to add an Android app to the project.
4. Register the app:
   • Android package name: Enter com.example.firebaseintegration.
   • Download the google-services.json file and place it in the app directory of your Android project.
5. Add Firebase SDK dependencies to your project:
   • Open build.gradle (Project level) and add the Google services classpath:

     buildscript { dependencies { ... classpath 'com.google.gms:google-services:4.3.15' }
     }
     

   • Open build.gradle (App level) and apply the Google services plugin:

     apply plugin: 'com.android.application'
     apply plugin: 'com.google.gms.google-services' dependencies { implementation platform('com.google.firebase:firebase-bom:32.4.1') implementation 'com.google.firebase:firebase-auth:22.3.1' implementation 'com.google.firebase:firebase-firestore:24.9.1' implementation 'com.google.firebase:firebase-messaging:23.3.1'
     }
     

6. Sync your project with Gradle files.

Step 3: Set Up Firebase Authentication

1. Enable Email/Password Authentication:

   • In the Firebase Console, go to "Authentication" > "Sign-in method".
   • Enable "Email/Password".

2. Create a Registration Activity:

   • Create a new activity RegisterActivity.java.
   • Add the following code to activity_register.xml:

     <LinearLayout xmlns:android=" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:padding="16dp"> <EditText android:id="@+id/email" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="Email" /> <EditText android:id="@+id/password" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="Password" android:inputType="textPassword" /> <Button android:id="@+id/registerButton" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="Register" />
     </LinearLayout>
     

   • Add the following code to RegisterActivity.java:

     import android.content.Intent;
     import android.os.Bundle;
     import android.view.View;
     import android.widget.Button;
     import android.widget.EditText;
     import android.widget.Toast;
     import androidx.annotation.NonNull;
     import androidx.appcompat.app.AppCompatActivity;
     import com.google.android.gms.tasks.OnCompleteListener;
     import com.google.android.gms.tasks.Task;
     import com.google.firebase.auth.AuthResult;
     import com.google.firebase.auth.FirebaseAuth; public class RegisterActivity extends AppCompatActivity { private EditText emailEditText, passwordEditText; private Button registerButton; private FirebaseAuth mAuth; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_register); emailEditText = findViewById(R.id.email); passwordEditText = findViewById(R.id.password); registerButton = findViewById(R.id.registerButton); mAuth = FirebaseAuth.getInstance(); registerButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String email = emailEditText.getText().toString(); String password = passwordEditText.getText().toString(); mAuth.createUserWithEmailAndPassword(email, password) .addOnCompleteListener(new OnCompleteListener<AuthResult>() { @Override public void onComplete(@NonNull Task<AuthResult> task) { if (task.isSuccessful()) { Toast.makeText(RegisterActivity.this, "Registration successful!", Toast.LENGTH_SHORT).show(); Intent intent = new Intent(RegisterActivity.this, LoginActivity.class); startActivity(intent); finish(); } else { Toast.makeText(RegisterActivity.this, task.getException().getMessage(), Toast.LENGTH_SHORT).show(); } } }); } }); }
     }
     

3. Create a Login Activity:

   • Create a new activity LoginActivity.java.
   • Add the following code to activity_login.xml:

     <LinearLayout xmlns:android=" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:padding="16dp"> <EditText android:id="@+id/email" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="Email" /> <EditText android:id="@+id/password" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="Password" android:inputType="textPassword" /> <Button android:id="@+id/loginButton" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="Login" />
     </LinearLayout>
     

   • Add the following code to LoginActivity.java:

     import android.content.Intent;
     import android.os.Bundle;
     import android.view.View;
     import android.widget.Button;
     import android.widget.EditText;
     import android.widget.Toast;
     import androidx.annotation.NonNull;
     import androidx.appcompat.app.AppCompatActivity;
     import com.google.android.gms.tasks.OnCompleteListener;
     import com.google.android.gms.tasks.Task;
     import com.google.firebase.auth.AuthResult;
     import com.google.firebase.auth.FirebaseAuth; public class LoginActivity extends AppCompatActivity { private EditText emailEditText, passwordEditText; private Button loginButton; private FirebaseAuth mAuth; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_login); emailEditText = findViewById(R.id.email); passwordEditText = findViewById(R.id.password); loginButton = findViewById(R.id.loginButton); mAuth = FirebaseAuth.getInstance(); loginButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String email = emailEditText.getText().toString(); String password = passwordEditText.getText().toString(); mAuth.signInWithEmailAndPassword(email, password) .addOnCompleteListener(new OnCompleteListener<AuthResult>() { @Override public void onComplete(@NonNull Task<AuthResult> task) { if (task.isSuccessful()) { Toast.makeText(LoginActivity.this, "Login successful!", Toast.LENGTH_SHORT).show(); Intent intent = new Intent(LoginActivity.this, MainActivity.class); startActivity(intent); finish(); } else { Toast.makeText(LoginActivity.this, task.getException().getMessage(), Toast.LENGTH_SHORT).show(); } } }); } }); }
     }
     

Step 4: Set Up Firebase Firestore

1. Enable Firestore in Firebase Console:

   • Go to "Firestore Database" and click "Create database".
   • Choose "Start in Test Mode" for the initial setup.

2. Add Firestore to MainActivity:

   • Create a new activity MainActivity.java.
   • Add the following code to activity_main.xml:

     <LinearLayout xmlns:android=" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:padding="16dp"> <EditText android:id="@+id/title" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="Title" /> <EditText android:id="@+id/description" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="Description" /> <Button android:id="@+id/addButton" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="Add Note" /> <ListView android:id="@+id/noteListView" android:layout_width="match_parent" android:layout_height="wrap_content" />
     </LinearLayout>
     

   • Add the following code to MainActivity.java:

     import android.os.Bundle;
     import android.view.View;
     import android.widget.ArrayAdapter;
     import android.widget.Button;
     import android.widget.EditText;
     import android.widget.ListView;
     import android.widget.Toast;
     import androidx.annotation.NonNull;
     import androidx.appcompat.app.AppCompatActivity;
     import com.google.firebase.auth.FirebaseAuth;
     import com.google.firebase.firestore.DocumentChange;
     import com.google.firebase.firestore.FirebaseFirestore;
     import com.google.firebase.firestore.QuerySnapshot;
     import java.util.ArrayList; public class MainActivity extends AppCompatActivity { private EditText titleEditText, descriptionEditText; private Button addButton; private ListView noteListView; private ArrayAdapter<String> adapter; private ArrayList<String> noteList; private FirebaseFirestore firestore; private FirebaseAuth mAuth; private String userId; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); titleEditText = findViewById(R.id.title); descriptionEditText = findViewById(R.id.description); addButton = findViewById(R.id.addButton); noteListView = findViewById(R.id.noteListView); firestore = FirebaseFirestore.getInstance(); mAuth = FirebaseAuth.getInstance(); userId = mAuth.getCurrentUser().getUid(); noteList = new ArrayList<>(); adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, noteList); noteListView.setAdapter(adapter); addButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String title = titleEditText.getText().toString(); String description = descriptionEditText.getText().toString(); firestore.collection("users").document(userId).collection("notes") .add(new Note(title, description)) .addOnCompleteListener(task -> { if (task.isSuccessful()) { Toast.makeText(MainActivity.this, "Note added", Toast.LENGTH_SHORT).show(); titleEditText.setText(""); descriptionEditText.setText(""); } else { Toast.makeText(MainActivity.this, task.getException().getMessage(), Toast.LENGTH_SHORT).show(); } }); } }); loadNotes(); } private void loadNotes() { firestore.collection("users").document(userId).collection("notes") .addSnapshotListener((value, error) -> { if (error != null) { Toast.makeText(MainActivity.this, error.getMessage(), Toast.LENGTH_SHORT).show(); return; } for (DocumentChange dc : value.getDocumentChanges()) { if (dc.getType() == DocumentChange.Type.ADDED) { Note note = dc.getDocument().toObject(Note.class); noteList.add(note.getTitle() + " - " + note.getDescription()); adapter.notifyDataSetChanged(); } } }); } private static class Note { private String title; private String description; public Note() { // Required empty constructor for Firestore } public Note(String title, String description) { this.title = title; this.description = description; } public String getTitle() { return title; } public String getDescription() { return description; } }
     }
     

Step 5: Set Up Firebase Cloud Messaging (FCM)

1. Enable FCM in Firebase Console:

   • Go to "Cloud Messaging" and note the Server key.

2. Add FCM to Your Project:

   • In the Firebase Console, go to "Cloud Messaging" > "Edit project settings" and configure the Cloud Messaging server key.
   • In the AndroidManifest.xml, add the following permissions and services:

     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.WAKE_LOCK" /> <application ...> <service android:name=".MyFirebaseMessagingService" android:exported="true"> <intent-filter> <action android:name="com.google.firebase.MESSAGING_EVENT" /> </intent-filter> </service> <service android:name=".MyFirebaseInstanceIDService" android:exported="true"> <intent-filter> <action android:name="com.google.firebase.INSTANCE_ID_EVENT" /> </intent-filter> </service>
     </application>
     

   • Create a new service MyFirebaseMessagingService.java:

     import android.app.NotificationChannel;
     import android.app.NotificationManager;
     import android.app.PendingIntent;
     import android.content.Context;
     import android.content.Intent;
     import android.graphics.Color;
     import android.os.Build;
     import androidx.annotation.NonNull;
     import androidx.core.app.NotificationCompat;
     import com.google.firebase.messaging.FirebaseMessagingService;
     import com.google.firebase.messaging.RemoteMessage; public class MyFirebaseMessagingService extends FirebaseMessagingService { private static final String CHANNEL_ID = "my_channel"; @Override public void onMessageReceived(@NonNull RemoteMessage remoteMessage) { super.onMessageReceived(remoteMessage); // Check if message contains a notification payload. if (remoteMessage.getNotification() != null) { createNotificationChannel(); sendNotification(remoteMessage.getNotification().getTitle(), remoteMessage.getNotification().getBody()); } } private void createNotificationChannel() { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) { NotificationChannel channel = new NotificationChannel( CHANNEL_ID, "Channel human readable title", NotificationManager.IMPORTANCE_DEFAULT); channel.setDescription("Channel description"); channel.enableLights(true); channel.setLightColor(Color.GREEN); channel.setVibrationPattern(new long[]{0, 1000, 500, 1000}); channel.enableVibration(true); NotificationManager manager = getSystemService(NotificationManager.class); manager.createNotificationChannel(channel); } } private void sendNotification(String title, String messageBody) { Intent intent = new Intent(this, MainActivity.class); intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); PendingIntent pendingIntent = PendingIntent.getActivity(this, 0 /* Request code */, intent, PendingIntent.FLAG_ONE_SHOT); NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this, CHANNEL_ID) .setSmallIcon(R.drawable.ic_launcher_foreground) .setContentTitle(title) .setContentText(messageBody) .setAutoCancel(true) .setContentIntent(pendingIntent); NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE); notificationManager.notify(0 /* ID of notification */, notificationBuilder.build()); }
     }
     

   • Create a new service MyFirebaseInstanceIDService.java (Note: This is no longer necessary for newer versions of Firebase. You can ignore this step and remove the corresponding service from the AndroidManifest.xml):

     import com.google.firebase.database.DatabaseReference;
     import com.google.firebase.database.FirebaseDatabase;
     import com.google.firebase.iid.FirebaseInstanceId;
     import com.google.firebase.iid.FirebaseInstanceIdService; public class MyFirebaseInstanceIDService extends FirebaseInstanceIdService { @Override public void onTokenRefresh() { super.onTokenRefresh(); String refreshedToken = FirebaseInstanceId.getInstance().getToken(); // You can send the token to your server or save it locally }
     }
     

Step 6: Test Your Application

1. Run the RegisterActivity from Android Studio.
2. Register a new user by entering an email and password.
3. Log in using the registered credentials.
4. Add notes in MainActivity and observe them in the list.
5. Send a test push notification from the Firebase Console to your app.

Conclusion

You now have a basic Android application integrated with Firebase Authentication, Firestore, and Cloud Messaging. This setup can be expanded with additional features such as user profiles, more complex data models, and enhanced push notifications.