I’m new to Android Studio and coding in general. I was tasked to develop a school group project. I was coding the sign-up page for the app and this issue suddenly popped up. It was working before when I haven’t configured the PhoneVerificationActivity to handle different intent sources. Firebase Auth sends the OTP but verifying it doesn’t seem to work now but the app does insert the user details in the Realtime Database and creates a folder in the Firebase Storage when I removed the OTP function for troubleshooting. I don’t know if it’s the IDE, Firebase setup, or my code.

Here are the source codes:

package com.example.best_csportal;

import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.ValueEventListener;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.storage.FirebaseStorage;
import com.google.firebase.storage.StorageReference;

public class RegistrationActivity extends AppCompatActivity {

    private static final int PHONE_VERIFICATION_REQUEST = 101;

    private EditText usernameEditText;
    private EditText phoneNumberEditText;
    private EditText passwordEditText;
    private EditText confirmPasswordEditText;
    private Button registerButton;
    private Button loginButton;
    private DatabaseReference databaseReference;
    private FirebaseAuth auth;

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

        // Initialize Firebase Auth
        auth = FirebaseAuth.getInstance();

        FirebaseDatabase database = FirebaseDatabase.getInstance("https://best-cs-default-rtdb.asia-southeast1.firebasedatabase.app");
        databaseReference = database.getReference("users");

        usernameEditText = findViewById(R.id.etext_rusername);
        phoneNumberEditText = findViewById(R.id.etext_rphone);
        passwordEditText = findViewById(R.id.etext_rpassword);
        confirmPasswordEditText = findViewById(R.id.etext_rcpassword);
        registerButton = findViewById(R.id.button_rregister);
        loginButton = findViewById(R.id.button_rlogin);

        registerButton.setOnClickListener(v -> initiatePhoneVerification());
        loginButton.setOnClickListener(v -> startActivity(new Intent(this, LoginActivity.class)));
    }

    private void initiatePhoneVerification() {
        String phoneNumber = phoneNumberEditText.getText().toString();
        Intent intent = new Intent(this, PhoneVerificationActivity.class);
        intent.putExtra("phoneNumber", phoneNumber);
        startActivityForResult(intent, PHONE_VERIFICATION_REQUEST);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == PHONE_VERIFICATION_REQUEST && resultCode == RESULT_OK) {
            registerUser();
        } else {
            Toast.makeText(this, "OTP verification failed. Please try again.", Toast.LENGTH_LONG).show();
        }
    }

    private void registerUser() {
        String username = usernameEditText.getText().toString().trim();
        String rawPhoneNumber = phoneNumberEditText.getText().toString().trim();
        String password = passwordEditText.getText().toString().trim();
        String confirmPassword = confirmPasswordEditText.getText().toString().trim();

        // Process the phone number for the desired format
        final String phoneNumber;
        if (rawPhoneNumber.startsWith("0")) {
            phoneNumber = rawPhoneNumber.replaceFirst("0", "+63");
        } else if (!rawPhoneNumber.startsWith("+63")) {
            phoneNumber = "+63" + rawPhoneNumber;
        } else {
            phoneNumber = rawPhoneNumber;
        }

        if (username.isEmpty() || phoneNumber.isEmpty() || password.isEmpty() || confirmPassword.isEmpty()) {
            Toast.makeText(this, "All fields must be filled", Toast.LENGTH_SHORT).show();
            return;
        }

        if (!password.equals(confirmPassword)) {
            Toast.makeText(this, "Passwords do not match", Toast.LENGTH_SHORT).show();
            return;
        }

        // Check for duplicate usernames
        databaseReference.orderByChild("username").equalTo(username).addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                if (dataSnapshot.exists()) {
                    Toast.makeText(RegistrationActivity.this, "Username already exists", Toast.LENGTH_SHORT).show();
                } else {
                    // Check for duplicate phone numbers
                    databaseReference.orderByChild("phoneNumber").equalTo(phoneNumber).addListenerForSingleValueEvent(new ValueEventListener() {
                        @Override
                        public void onDataChange(DataSnapshot phoneSnapshot) {
                            if (phoneSnapshot.exists()) {
                                Toast.makeText(RegistrationActivity.this, "Phone number already used", Toast.LENGTH_SHORT).show();
                            } else {
                                // Register user in the Realtime Database
                                String userId = databaseReference.push().getKey();
                                String folderPath = "users/" + userId + "/";
                                User user = new User(username, phoneNumber, password, folderPath);
                                databaseReference.child(userId).setValue(user)
                                        .addOnCompleteListener(dbTask -> {
                                            if (dbTask.isSuccessful()) {
                                                createUserFolder(userId);
                                                Toast.makeText(RegistrationActivity.this, "Registration Successful", Toast.LENGTH_SHORT).show();
                                            } else {
                                                Toast.makeText(RegistrationActivity.this, "Registration Failed: " + dbTask.getException().getMessage(), Toast.LENGTH_SHORT).show();
                                            }
                                        });
                            }
                        }

                        @Override
                        public void onCancelled(DatabaseError databaseError) {
                            Toast.makeText(RegistrationActivity.this, "Error: " + databaseError.getMessage(), Toast.LENGTH_SHORT).show();
                        }
                    });
                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
                Toast.makeText(RegistrationActivity.this, "Error: " + databaseError.getMessage(), Toast.LENGTH_SHORT).show();
            }
        });
    }

    private void createUserFolder(String userId) {
        FirebaseStorage storage = FirebaseStorage.getInstance();
        StorageReference storageRef = storage.getReference();
        StorageReference userFolder = storageRef.child("users/" + userId + "/");

        // Create a dummy file to initialize the folder
        StorageReference dummyFile = userFolder.child("dummy.txt");
        byte[] data = "This is a placeholder to create the folder".getBytes();
        dummyFile.putBytes(data).addOnSuccessListener(aVoid -> {
            // Successfully created folder, now update the database
            databaseReference.child(userId).child("storagePath").setValue(userFolder.getPath())
                    .addOnFailureListener(e -> Toast.makeText(RegistrationActivity.this, "Failed to save storage path: " + e.getMessage(), Toast.LENGTH_SHORT).show());
        }).addOnFailureListener(exception -> {
            // Handle unsuccessful uploads
            Toast.makeText(RegistrationActivity.this, "Failed to create user folder: " + exception.getMessage(), Toast.LENGTH_SHORT).show();
        });
    }
}

package com.example.best_csportal;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.PhoneAuthCredential;
import com.google.firebase.auth.PhoneAuthProvider;
import java.util.concurrent.TimeUnit;
import com.google.firebase.FirebaseException;
import android.util.Log;
import android.app.Activity;

public class PhoneVerificationActivity extends AppCompatActivity {

    private EditText editTextCode;
    private Button buttonVerify;
    private FirebaseAuth mAuth;
    private String phoneNumber;
    private String verificationId;

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

        mAuth = FirebaseAuth.getInstance();
        editTextCode = findViewById(R.id.editTextCode);
        buttonVerify = findViewById(R.id.buttonVerify);

        // Retrieve the phone number passed from LoginActivity
        phoneNumber = getIntent().getStringExtra("phoneNumber");

        sendVerificationCodeToUser(phoneNumber);

        buttonVerify.setOnClickListener(v -> {
            String code = editTextCode.getText().toString().trim();
            if (!code.isEmpty()) {
                verifyVerificationCode(code);
            }
        });
    }

    private void sendVerificationCodeToUser(String phoneNumber) {
        PhoneAuthProvider.getInstance().verifyPhoneNumber(
                phoneNumber,        // Phone number to verify
                60,                 // Timeout duration
                TimeUnit.SECONDS,   // Unit of timeout
                this,               // Activity (for callback binding)
                new PhoneAuthProvider.OnVerificationStateChangedCallbacks() {
                    @Override
                    public void onVerificationCompleted(PhoneAuthCredential credential) {
                        // Auto-verification logic here
                        signInWithPhoneAuthCredential(credential);
                    }

                    @Override
                    public void onVerificationFailed(FirebaseException e) {
                        Log.e("PhoneVerification", "Verification failed: " + e.getMessage());
                        Toast.makeText(PhoneVerificationActivity.this, "Verification failed: " + e.getMessage(), Toast.LENGTH_SHORT).show();
                    }

                    @Override
                    public void onCodeSent(String verificationId, PhoneAuthProvider.ForceResendingToken token) {
                        Log.d("PhoneVerification", "Code sent successfully");
                        PhoneVerificationActivity.this.verificationId = verificationId; // Save the verification ID for later use
                    }
                }
        );
    }

    private void verifyVerificationCode(String code) {
        PhoneAuthCredential credential = PhoneAuthProvider.getCredential(verificationId, code);
        signInWithPhoneAuthCredential(credential);
    }

    private void signInWithPhoneAuthCredential(PhoneAuthCredential credential) {
        mAuth.signInWithCredential(credential)
                .addOnCompleteListener(this, task -> {
                    if (task.isSuccessful()) {
                        String sourceActivity = getIntent().getStringExtra("sourceActivity");
                        if ("RegistrationActivity".equals(sourceActivity)) {
                            Intent resultIntent = new Intent();
                            setResult(Activity.RESULT_OK, resultIntent);
                            finish();
                        } else if ("LoginActivity".equals(sourceActivity)) {
                            Intent intent = new Intent(PhoneVerificationActivity.this, UserMainActivity.class);
                            startActivity(intent);
                            finish();
                        }
                    } else {
                        Toast.makeText(PhoneVerificationActivity.this, "Verification failed: " + task.getException().getMessage(), Toast.LENGTH_LONG).show();
                        setResult(Activity.RESULT_CANCELED);
                        finish();
                    }
                });
    }
}

I tried rebuilding the project. I checked my dependencies. I also tried running the app on an Android phone that I paired with Android Studio. I also tried adding AppCheck to see if that works but nope.