Halo selamat siang pada kesempatan kali ini kita akan membuat halaman Login di Android dengan Firebase, untuk membuat login dengan Firebase sangat mudah kita tinggal memanfaatkan fungsi authentikasi dari firebase, fungsi authentikasi firebase ini sangat lengkap kita bisa login lewat facebook, google akun, twitter, email, no handphone dll, namun yang akan kita bahas pada tutorial kali ini yaitu login lewat Email dan Password.

Untuk membuat Login dengan Email/Password di Firebase Langkah pertama kita aktifkan dulu signin method nya di Firebase Console, caranya yaitu anda Login dulu ke Firebase kemudian pilih projek anda yang akan menggunakan authentikasi kemudian pada tab develop di samping kiri pilih authentication -> sign-in method -> pilih provider yang akan digunakan untuk melakukan authentikasi disini saya menggunakan provider Email/Password -> pada status pilih enable.

kemudian pada tab users tambahkan user yang akan digunakan untuk login nantinya karena pada tutorial kali ini kita tidak akan membuat register jadi usernya dimasukan secara manual dari firebase

selanjutnya buat activity baru dan tambhkan dua buah editTeks untuk email dan password kemudian tambhkan sebuah button untuk submit, atur tampilanya agar terlihat lebih cantik seperti ini:

xml version="1.0" encoding="utf-8"?>

xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:app="http://schemas.android.com/apk/res-auto"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:padding="10dp"

    android:background="@color/colorPrimary"

    tools:context="giviews.id.fireapp.LoginActivity">



    
        android:id="@+id/logoImage"

        android:layout_width="100dp"

        android:layout_height="130dp"

        android:layout_marginTop="20dp"

        android:layout_centerHorizontal="true"

        android:src="@drawable/logo"

        android:textAlignment="center" />



    
        android:id="@+id/txtLogo"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="Firebase Login"

        android:gravity="center"

        android:textColor="#ffffff"

        android:layout_below="@+id/logoImage"

        android:textSize="25sp"/>



    
        android:id="@+id/email"

        android:background="@drawable/input_background"

        android:padding="15dp"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:hint="Email ..."

        android:textColor="#807f7f"

        android:layout_below="@+id/txtLogo"

        android:layout_marginTop="60dp"

        android:inputType="textEmailAddress" />



    
        android:id="@+id/password"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:hint="Password ..."

        android:background="@drawable/input_background"

        android:padding="15dp"

        android:textColor="#807f7f"

        android:layout_marginTop="20dp"

        android:layout_below="@+id/email"

        android:inputType="textPassword" />



        android:id="@+id/loginBtn"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_below="@+id/password"

        android:background="@drawable/btn_background"

        android:padding="15dp"

        android:textColor="@color/colorPrimary"

        android:layout_marginTop="20dp"

        android:textSize="20dp"

        android:text="Sign In"/>

xml version="1.0" encoding="utf-8"?>

xmlns:android="http://schemas.android.com/apk/res/android">

    android:color="#fff" />

    android:radius="5dp" />

xml version="1.0" encoding="utf-8"?>

xmlns:android="http://schemas.android.com/apk/res/android">

    android:color="@color/colorAccent" />

    android:radius="5dp" />

package giviews.id.fireapp;



import android.content.Intent;

import android.support.annotation.NonNull;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.text.TextUtils;

import android.view.View;

import android.view.WindowManager;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;



import com.google.android.gms.tasks.OnCompleteListener;

import com.google.android.gms.tasks.Task;

import com.google.firebase.auth.AuthResult;

import com.google.firebase.auth.FirebaseAuth;



public class LoginActivity extends AppCompatActivity {



    private EditText mEmailField;

    private EditText mPasswordField;

    private Button mloginBtn;



    private FirebaseAuth mAuth;

    private FirebaseAuth.AuthStateListener mAuthListener;



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_login);



        //Membuat FullScreen

        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);



        mEmailField = (EditText) findViewById(R.id.email);

        mPasswordField = (EditText) findViewById(R.id.password);

        mloginBtn = (Button) findViewById(R.id.loginBtn);



        mAuth = FirebaseAuth.getInstance();



        mAuthListener = new FirebaseAuth.AuthStateListener() {

            @Override

            public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {

                if (firebaseAuth.getCurrentUser() != null) {

                    startActivity(new Intent(LoginActivity.this, MainActivity.class) );

                }

            }

        };



        mloginBtn.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                startSignIn();

            }

        });

    }



    @Override

    protected void onStart() {

        super.onStart();



        mAuth.addAuthStateListener(mAuthListener);

    }



    private void startSignIn() {

        String email = mEmailField.getText().toString();

        String password = mPasswordField.getText().toString();



        if (TextUtils.isEmpty(email) | TextUtils.isEmpty(password)) {

            Toast.makeText(LoginActivity.this, "Fields are Empty", Toast.LENGTH_SHORT).show();

        } else {



            mAuth.signInWithEmailAndPassword(email, password).addOnCompleteListener(new OnCompleteListener() {

                @Override

                public void onComplete(@NonNull Task task) {



                    if (!task.isSuccessful()) {

                        Toast.makeText(LoginActivity.this, "Login Problem", Toast.LENGTH_SHORT).show();

                    }



                }

            });

        }

    }

}

package com.giviews.giviewsmessenger;



import android.app.ProgressDialog;

import android.content.Intent;

import android.support.annotation.NonNull;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.support.v7.widget.Toolbar;

import android.text.TextUtils;

import android.util.Log;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;



import com.google.android.gms.tasks.OnCompleteListener;

import com.google.android.gms.tasks.Task;

import com.google.firebase.auth.AuthResult;

import com.google.firebase.auth.FirebaseAuth;

import com.google.firebase.auth.FirebaseAuthInvalidCredentialsException;

import com.google.firebase.auth.FirebaseAuthUserCollisionException;

import com.google.firebase.auth.FirebaseAuthWeakPasswordException;

import com.google.firebase.auth.FirebaseUser;

import com.google.firebase.database.DatabaseReference;

import com.google.firebase.database.FirebaseDatabase;

import com.google.firebase.iid.FirebaseInstanceId;



import java.util.HashMap;



public class RegisterActivity extends AppCompatActivity {



    private EditText mDisplayName;

    private EditText mEmail;

    private EditText mPassword;

    private Button mCreateBtn;

    private Toolbar mToolbar;

    private ProgressDialog mProgress;



    private FirebaseAuth mAuth;

    private DatabaseReference mDatabase;



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_register);



        mAuth = FirebaseAuth.getInstance();

        mDatabase = FirebaseDatabase.getInstance().getReference().child("Users");

        mToolbar = (Toolbar) findViewById(R.id.main_page_toolbar);

        setSupportActionBar(mToolbar);

        getSupportActionBar().setTitle("Register");

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);



        mDisplayName = (EditText) findViewById(R.id.reg_name);

        mEmail = (EditText) findViewById(R.id.reg_email);

        mPassword = (EditText) findViewById(R.id.reg_password);

        mCreateBtn = (Button) findViewById(R.id.reg_create_btn);

        mProgress = new ProgressDialog(this);



        mCreateBtn.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View view) {

                String displayname = mDisplayName.getText().toString().trim();

                String email = mEmail.getText().toString().trim();

                String password = mPassword.getText().toString().trim();



                if (!TextUtils.isEmpty(displayname) && !TextUtils.isEmpty(email) && !TextUtils.isEmpty(password)) {

                    mProgress.setTitle("Registering User");

                    mProgress.setMessage("Please wait while we create your account...");

                    mProgress.setCanceledOnTouchOutside(false);

                    mProgress.show();



                    register_user(displayname, email, password);

                }

            }

        });

    }



    private void register_user(final String displayname, String email, String password) {

        mAuth.createUserWithEmailAndPassword(email, password)

                .addOnCompleteListener(this, new OnCompleteListener() {

                    @Override

                    public void onComplete(@NonNull Task task) {



                        // If sign in fails, display a message to the user. If sign in succeeds

                        // the auth state listener will be notified and logic to handle the

                        // signed in user can be handled in the listener.

                        if (!task.isSuccessful()) {

                            mProgress.hide();



                            String error = "";

                            try {

                                throw task.getException();

                            } catch (FirebaseAuthWeakPasswordException e) {

                                error = "Weak Password";

                            } catch (FirebaseAuthInvalidCredentialsException e) {

                                error = "Invalid Email";

                            } catch (FirebaseAuthUserCollisionException e) {

                                error = "Existing account";

                            } catch (Exception e) {

                                error = "Unknown Error!";

                                e.printStackTrace();

                            }

                            Toast.makeText(getApplicationContext(), error, Toast.LENGTH_SHORT).show();

                        }else {

                            FirebaseUser currentUser = mAuth.getCurrentUser();

                            String uid = currentUser.getUid();



                            mDatabase = FirebaseDatabase.getInstance().getReference().child("Users").child(uid);

                            String device_token = FirebaseInstanceId.getInstance().getToken();



                            HashMap, String> userMap = new HashMap, String>();

                            userMap.put("name", displayname);

                            userMap.put("status", "Hi there, I'm using giviews");

                            userMap.put("image", "default");

                            userMap.put("thumb_image", "default");

                            userMap.put("device_token", device_token);



                            mDatabase.setValue(userMap).addOnCompleteListener(new OnCompleteListener() {

                                @Override

                                public void onComplete(@NonNull Task task) {

                                    mProgress.dismiss();

                                    Intent mainIntent = new Intent(RegisterActivity.this, MainActivity.class);

                                    mainIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);

                                    startActivity(mainIntent);

                                }

                            });



                        }

                    }

                });

    }

}