Check Phone Number Availablity in firebase realtime | if Phone Number Available then got Name, Email id in textview

1. Activity (activity_main.xml)

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:padding="16dp"> <!-- Phone Number Input --> <EditText android:id="@+id/phoneEditText" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="Enter Phone Number" android:inputType="phone" android:padding="10dp" android:textSize="16sp"/> <!-- Button to Check Phone Number --> <Button android:id="@+id/checkPhoneButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Check Phone Number" android:layout_marginTop="16dp"/> <!-- Result TextViews --> <TextView android:id="@+id/nameTextView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:text="Name: " android:textSize="16sp" /> <TextView android:id="@+id/emailTextView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Email: " android:textSize="16sp"/> <TextView android:id="@+id/pin" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="pin: " android:textSize="16sp"/> </LinearLayout>

1. Activity (mainactivity.java)

// Import necessary Firebase and Android libraries import androidx.annotation.NonNull; import androidx.appcompat.app.AppCompatActivity; import android.annotation.SuppressLint; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; import com.google.firebase.database.DataSnapshot; import com.google.firebase.database.DatabaseError; import com.google.firebase.database.DatabaseReference; import com.google.firebase.database.FirebaseDatabase; import com.google.firebase.database.ValueEventListener; public class MainActivity extends AppCompatActivity { private EditText phoneEditText; private Button checkPhoneButton; private TextView nameTextView, emailTextView,pin; private DatabaseReference mDatabase; @SuppressLint("MissingInflatedId") @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // Initialize UI elements phoneEditText = findViewById(R.id.phoneEditText); checkPhoneButton = findViewById(R.id.checkPhoneButton); nameTextView = findViewById(R.id.nameTextView); emailTextView = findViewById(R.id.emailTextView); pin = findViewById(R.id.pin); // Initialize Firebase Database reference mDatabase = FirebaseDatabase.getInstance().getReference("phoneNumbers"); // Set onClickListener for the button checkPhoneButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String phoneNumber = phoneEditText.getText().toString().trim(); if (!phoneNumber.isEmpty()) { checkPhoneNumberInDatabase(phoneNumber); } else { nameTextView.setText("Please enter a phone number."); emailTextView.setText(""); } } }); } // Method to check if the phone number exists and get associated details private void checkPhoneNumberInDatabase(final String phoneNumber) { mDatabase.child(phoneNumber).addListenerForSingleValueEvent(new ValueEventListener() { @Override public void onDataChange(@NonNull DataSnapshot dataSnapshot) { if (dataSnapshot.exists()) { // Phone number exists, retrieve name and email String name = dataSnapshot.child("Name").getValue(String.class); String email = dataSnapshot.child("Email").getValue(String.class); String pi = dataSnapshot.child("Pins").getValue(String.class); nameTextView.setText("Name: " + name); emailTextView.setText("Email: " + email); pin.setText("Pin: "+pi); } else { // Phone number does not exist nameTextView.setText("Phone number not found in database."); emailTextView.setText(""); } } @Override public void onCancelled(@NonNull DatabaseError databaseError) { // Handle potential errors nameTextView.setText("Error: " + databaseError.getMessage()); emailTextView.setText(""); } }); } }