package com.arslan6015.firebaseauthusingphoneno; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import androidx.appcompat.app.AppCompatActivity; import com.google.firebase.auth.FirebaseAuth; import com.google.firebase.auth.FirebaseUser; public class MainActivity extends AppCompatActivity { private EditText editTextMobile; Button btnContinue; FirebaseUser currentUser; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //initialize fields editTextMobile = findViewById(R.id.editTextMobile); btnContinue = findViewById(R.id.buttonContinue); currentUser = FirebaseAuth.getInstance().getCurrentUser(); //check whether the user is logged in if (currentUser != null) { Intent intent = new Intent(MainActivity.this, ProfileActivity.class); startActivity(intent); finish(); } else { btnContinue.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String mobileNo = editTextMobile.getText().toString().trim(); if (mobileNo.isEmpty() || mobileNo.length() < 12) { editTextMobile.setError("Enter a valid mobile"); editTextMobile.requestFocus(); return; } Intent intent = new Intent(MainActivity.this, VerifyPhoneActivity.class); intent.putExtra("mobile", mobileNo); startActivity(intent); } }); } } }