In the first part, the Registration and the Sign In activity were created. Also, the app was linked to the Firebase console.
Once your app is connected to Firebase, select the app in your Firebase console. From there choose the Authentication tab on the left side of the screen.
So this is the tab you will use to control how users are authenticated in your app. In the top to the screen select Sign-In method . As you will see a list of the many Firebase Sign- In Methods but this tutorial will just be demonstrating Email and Password Sign In method.
Be Sure to select the Email/Password method and Enable the feature.
That’s all for the console portion of the tutorial for now. The next part will be coding the Java files in Android Studio.
Starting with the Register.java there are three main sections that need to be coded. The first would be setting the variables, calling OnClickMethod and lastly the Firbebase Auth.
The below portion of code creates and sets the variables and connects the app to Firebase. It also checks if the users already exist, if the user already has an account they will be Auto-Signed In.
public class Register extends AppCompatActivity {
///Creating the Variables
private FirebaseAuth mAuth;
private FirebaseAuth.AuthStateListener firebaseAuthStateListener;
private Button mSiginUp;
private EditText mEmail, xPassword, mPassword;
private TextView Already;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
/// Connecting Firebase to the app
FirebaseApp.initializeApp(this);
mAuth = FirebaseAuth.getInstance();
/// If User Already Exist, if so they Will be auto-Signed in
firebaseAuthStateListener = new
FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth
firebaseAuth) {
final FirebaseUser user =
FirebaseAuth.getInstance().getCurrentUser();
if (user !=null){
Intent intent = new Intent(Register.this,
MainActivity.class);
startActivity(intent);
finish();
return;
}
}
};
///Setting the variables from the layout.
mSiginUp = findViewById(R.id.button_create);
mEmail = findViewById(R.id.editText_email);
xPassword = findViewById(R.id.editText_password);
mPassword = findViewById(R.id.editText_passconfirm);
This below portion of code sets the OnClickMethod and creates a new account for the user when they click the button.
/// OnClickMethod for Button
mSiginUp.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final String email = mEmail.getText().toString();
final String xpassword = xPassword.getText().toString();
final String password = mPassword.getText().toString();
/// Checking if Passwords Match
if
(!xPassword.getText().toString().equals(mPassword.getText().toString()
))
{
Toast.makeText(Register.this, "Must Match!",
Toast.LENGTH_SHORT).show();
}
/// Authorizing users to Firebase
mAuth.createUserWithEmailAndPassword(email,
password).addOnCompleteListener(Register.this, new
OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull
Task<AuthResult> task) {
if (!task.isSuccessful()) {
Toast.makeText(Register.this, "sign up error",
Toast.LENGTH_SHORT).show();
} else {
/// If user is created move to Main Activity
Intent intent = new Intent(Register.this,
MainActivity.class);
startActivity(intent);
finish();
}
}
});
}
});
}
@Override
protected void onStart() {
super.onStart();
mAuth.addAuthStateListener(firebaseAuthStateListener);
}
@Override
protected void onStop() {
super.onStop();
mAuth.removeAuthStateListener(firebaseAuthStateListener);
}
public void already(View view) {
Intent intent = new Intent(Register.this, SignIn.class);
startActivity(intent);
finish();
}
}
Code It 