SignUpActivity.java

import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.Toast;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;

public class SignUpActivity extends AppCompatActivity {

    EditText emailInput;
    EditText passwordInput;
    EditText fullnameInput;

    ProgressBar progressBar;

    FirebaseAuth mAuth;
    DatabaseReference mRootRef, mUserRef;
    FirebaseDatabase mDatabase;

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

        mDatabase = FirebaseDatabase.getInstance();
        mRootRef = mDatabase.getReference();

        mAuth = FirebaseAuth.getInstance();

        emailInput = findViewById(R.id.email);
        passwordInput = findViewById(R.id.password);
        fullnameInput = findViewById(R.id.fullname);
        progressBar = findViewById(R.id.progressBar);

        Button signUpButton = findViewById(R.id.signUp);
        Button signInButton = findViewById(R.id.signIn);

        signInButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(SignUpActivity.this,
                        SignInActivity.class));
                finish();
            }
        });

        signUpButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                signUp();
            }
        });
    }

    private void signUp() {
        String email = emailInput.getText().toString();
        String fullname = fullnameInput.getText().toString();
        String password = passwordInput.getText().toString();

        if (email.isEmpty()) {
            emailInput.setError("Email harus diisi!");
            return;
        }

        if (fullname.isEmpty()) {
            fullnameInput.setError("Fullname harus diisi!");
            return;
        }

        if (password.isEmpty()) {
            passwordInput.setError("Password harus diisi!");
            return;
        }

        progressBar.setVisibility(View.VISIBLE);

        mAuth.createUserWithEmailAndPassword(email, password)
                .addOnCompleteListener(new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if (task.isSuccessful()) {
                            saveUser(fullname, email);
                        } else {
                            progressBar.setVisibility(View.INVISIBLE);
                            Toast.makeText(
                                    SignUpActivity.this,
                                    task.getException().getMessage(),
                                    Toast.LENGTH_LONG
                            ).show();
                        }
                    }
                });
    }

    private void saveUser(String fullname, String email) {
        mUserRef = mRootRef.child("user");
        String userId = mAuth.getUid();

        User user = new User(fullname, email);
        mUserRef.child(userId).setValue(user).addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                if (task.isSuccessful()) {
                    progressBar.setVisibility(View.INVISIBLE);
                    Intent intent = new Intent(SignUpActivity.this,
                            HomeActivity.class);
                    startActivity(intent);
                    finish();
                } else {
                    progressBar.setVisibility(View.INVISIBLE);
                    Toast.makeText(
                            SignUpActivity.this,
                            task.getException().getMessage(),
                            Toast.LENGTH_LONG
                    ).show();
                }
            }
        });
    }
}