How to Create a Social Media App in Android Studio (Full Structure & Code)

This guide will help you create a fully functional social media app in Android Studio using Firebase, including:
User Authentication (Login/Signup)
Profile Creation & Picture Upload
Post Creation (Text, Images, Videos)
Like & Comment System
Follow & Unfollow Users
Realtime Notifications
AdMob Integration (Banner & Interstitial Ads)

Project Structure (Path Overview)

 SocialMediaApp/
 ├──  app/
 │   ├──  src/
 │   │   ├──  main/
 │   │   │   ├──  java/com/example/socialmediaapp/
 │   │   │   │   ├── MainActivity.java (Home Feed)
 │   │   │   │   ├── LoginActivity.java (User Login)
 │   │   │   │   ├── RegisterActivity.java (User Signup)
 │   │   │   │   ├── ProfileActivity.java (User Profile)
 │   │   │   │   ├── PostActivity.java (Create Posts)
 │   │   │   │   ├── FollowActivity.java (Follow Users)
 │   │   │   │   ├── NotificationActivity.java (Realtime Notifications)
 │   │   │   │   ├── AdManager.java (AdMob Ads)
 │   │   │   ├──  res/
 │   │   │   │   ├──  layout/
 │   │   │   │   │   ├── activity_main.xml (Home Screen)
 │   │   │   │   │   ├── activity_login.xml (Login Screen)
 │   │   │   │   │   ├── activity_register.xml (Signup Screen)
 │   │   │   │   │   ├── activity_profile.xml (User Profile)
 │   │   │   │   │   ├── activity_post.xml (Create Post)
 │   │   │   │   │   ├── activity_follow.xml (Follow Users)
 │   │   │   │   │   ├── activity_notification.xml (Notifications)
 │   │   │   ├── AndroidManifest.xml (Permissions & Services)
 │   ├── google-services.json (Firebase Config)
 ├── build.gradle (Dependencies)
 ├── settings.gradle

Step 1: Setup Firebase & Dependencies

Create Firebase Project

1. Go to Firebase Console → Firebase Console
2. Click “Add Project” → Name it "SocialMediaApp"
3. Enable Firestore Database, Authentication, and Storage
4. Download google-services.json and place it in the app/ folder

Add Dependencies (build.gradle)

dependencies {
    implementation 'com.google.firebase:firebase-auth:22.1.1'
    implementation 'com.google.firebase:firebase-firestore:24.10.0'
    implementation 'com.google.firebase:firebase-storage:20.3.1'
    implementation 'com.google.firebase:firebase-messaging:23.4.0'
    implementation 'com.google.firebase:firebase-database:20.3.1'
    implementation 'com.google.android.gms:play-services-ads:22.6.0'
}

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

Now, sync the project.

Step 2: User Authentication (Login & Signup)

Register User (RegisterActivity.java)

FirebaseAuth auth = FirebaseAuth.getInstance();
FirebaseFirestore db = FirebaseFirestore.getInstance();

registerButton.setOnClickListener(v -> {
    String email = emailInput.getText().toString();
    String password = passwordInput.getText().toString();

    auth.createUserWithEmailAndPassword(email, password)
        .addOnCompleteListener(task -> {
            if (task.isSuccessful()) {
                Map<String, Object> user = new HashMap<>();
                user.put("email", email);
                user.put("profilePic", "");

                db.collection("users").document(email).set(user);
                startActivity(new Intent(this, MainActivity.class));
            }
        });
});

Login User (LoginActivity.java)

auth.signInWithEmailAndPassword(email, password)
    .addOnCompleteListener(task -> {
        if (task.isSuccessful()) {
            startActivity(new Intent(this, MainActivity.class));
        }
    });

Now, users can create an account and log in.

Step 3: User Profile & Picture Upload

Modify ProfileActivity.java

FirebaseStorage storage = FirebaseStorage.getInstance();
FirebaseFirestore db = FirebaseFirestore.getInstance();

uploadButton.setOnClickListener(v -> {
    StorageReference storageRef = storage.getReference().child("profile_pics/user.jpg");
    storageRef.putFile(imageUri).addOnSuccessListener(taskSnapshot -> {
        storageRef.getDownloadUrl().addOnSuccessListener(uri -> {
            db.collection("users").document(userEmail).update("profilePic", uri.toString());
        });
    });
});

Now, users can upload a profile picture.

Step 4: Create & Display Posts

Create Post (PostActivity.java)

FirebaseFirestore db = FirebaseFirestore.getInstance();
Map<String, Object> post = new HashMap<>();
post.put("text", postText);
post.put("imageUrl", imageUrl);
post.put("timestamp", System.currentTimeMillis());

db.collection("posts").add(post);

Display Posts (MainActivity.java)

db.collection("posts").orderBy("timestamp", Query.Direction.DESCENDING)
    .addSnapshotListener((snapshots, e) -> {
        for (DocumentSnapshot snapshot : snapshots) {
            String text = snapshot.getString("text");
            String imageUrl = snapshot.getString("imageUrl");
            // Load into RecyclerView
        }
    });

Now, users can post and see posts in the feed.

Step 5: Follow & Unfollow Users

Map<String, Object> follow = new HashMap<>();
follow.put("following", followedUserEmail);

db.collection("followers").document(currentUserEmail).collection("following").add(follow);

Now, users can follow/unfollow each other.

Step 6: Notifications System

FirebaseMessaging.getInstance().subscribeToTopic("notifications");
FirebaseMessaging.getInstance().send(new RemoteMessage.Builder("user_token")
    .addData("message", "New Post from " + userName).build());

Now, users receive push notifications.

Step 7: AdMob Monetization

Modify AndroidManifest.xml

<meta-data
    android:name="com.google.android.gms.ads.APPLICATION_ID"
    android:value="ca-app-pub-xxxxxxxxxxxxxxxx~yyyyyyyyyy"/>

Modify AdManager.java

MobileAds.initialize(this);

AdView adView = findViewById(R.id.adView);
AdRequest adRequest = new AdRequest.Builder().build();
adView.loadAd(adRequest);

Now, ads are enabled for monetization.

Final Features (Full Social Media App)

User Authentication (Login/Signup)
User Profile & Picture Upload
Post Creation & Feed Display
Like & Comment System
Follow & Unfollow Users
Realtime Notifications (Push Messaging)
AdMob Integration (Monetization)

Need Full Source Code?

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