login.java

package com.classroom.app1;

// implementation 'com.google.firebase:firebase-core:16.0.7'

/*
1- Edittext -> IDs Layouts 
2- Register.java init Edit text -> findviewbyid
3- implement View.OnClickListener -> implement method (OnClick) definit lcode onclick if(i = R.id.view)
4- Button -> findviewbyid().setOnCliickListenner ...
5- copier coller lcode

*/

<uses-permission android:name="android.permission.INTERNET" />

import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.RequiresApi;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

import com.classroom.app1.UI.HomeActivity;
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.FirebaseUser;

public class Login extends BaseActivity implements View.OnClickListener {

    private static final String TAG = "EmailPassword";

    private EditText mEmailField;
    private EditText mPasswordField;

    // [START declare_auth]
    private FirebaseAuth mAuth;

    // [END declare_auth]

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.login);


        // Views
        mEmailField = findViewById(R.id.fieldEmail);
        mPasswordField = findViewById(R.id.fieldPassword);

        // Buttons
        findViewById(R.id.emailSignInButton).setOnClickListener(this);
        findViewById(R.id.emailCreateAccountButton).setOnClickListener(this);


        // [START initialize_auth]
        // Initialize Firebase Auth
        mAuth = FirebaseAuth.getInstance();
        // [END initialize_auth]
    }

    // [START on_start_check_user]
    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    @Override
    public void onStart() {
        super.onStart();
        // Check if user is signed in (non-null) and update UI accordingly.
        FirebaseUser currentUser = mAuth.getCurrentUser();
        updateUI(currentUser);
    }
    // [END on_start_check_user]


    private void signIn(String email, String password) {
        Log.d(TAG, "signIn:" + email);
        if (!validateForm()) {
            return;
        }

        showProgressDialog();

        // [START sign_in_with_email]
        mAuth.signInWithEmailAndPassword(email, password)
                .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if (task.isSuccessful()) {
                            // Sign in success, update UI with the signed-in user's information
                            Log.d(TAG, "signInWithEmail:success");
                            FirebaseUser user = mAuth.getCurrentUser();
                            updateUI(user);
                            Intent my = new Intent(Login.this, HomeActivity.class);
                            startActivity(my);
                            finish();
                            Toast.makeText(Login.this, "Authentication Success.",
                                    Toast.LENGTH_SHORT).show();

                        } else {
                            // If sign in fails, display a message to the user.
                            Log.w(TAG, "signInWithEmail:failure", task.getException());
                            Toast.makeText(Login.this, "Authentication failed.",
                                    Toast.LENGTH_SHORT).show();
                            updateUI(null);
                        }

                        // [START_EXCLUDE]
                        hideProgressDialog();
                        // [END_EXCLUDE]
                    }
                });
        // [END sign_in_with_email]
    }




    private boolean validateForm() {
        boolean valid = true;

        String email = mEmailField.getText().toString();
        if (TextUtils.isEmpty(email)) {
            mEmailField.setError("Requise");
            valid = false;
        } else {
            mEmailField.setError(null);
        }

        String password = mPasswordField.getText().toString();
        if (TextUtils.isEmpty(password)) {
            mPasswordField.setError("Requise");
            valid = false;
        } else {
            mPasswordField.setError(null);
        }

        return valid;
    }

    private void updateUI(FirebaseUser user) {
        hideProgressDialog();
        if (user != null) {
                    user.getEmail();
                    user.isEmailVerified();
        }
    }

    @Override
    public void onClick(View v) {
        int i = v.getId();
        if (i == R.id.emailCreateAccountButton) {
            Intent my = new Intent(this,Register.class);
            startActivity(my);
        } else if (i == R.id.emailSignInButton) {
            signIn(mEmailField.getText().toString(), mPasswordField.getText().toString());
        }
    }
}

Register.java

package com.classroom.app1;

import android.content.Intent;
import android.os.Bundle;
        import android.support.annotation.NonNull;
        import android.text.TextUtils;
        import android.util.Log;
        import android.view.View;
        import android.widget.EditText;
        import android.widget.TextView;
        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.FirebaseUser;


public class Register extends BaseActivity implements
        View.OnClickListener {

    private static final String TAG = "EmailPassword";

    private EditText mNomField;
    private EditText mPrenomField;
    private EditText mEmailField;
    private EditText mPasswordField;
    private EditText mRepasswordField;
    // [START declare_auth]
    private FirebaseAuth mAuth;
    // [END declare_auth]

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.register);

        // Views
        mNomField = findViewById(R.id.fieldNom);
        mPrenomField = findViewById(R.id.fieldPrenom);
        mEmailField = findViewById(R.id.fieldEmail);
        mPasswordField = findViewById(R.id.fieldPassword);
        mRepasswordField = findViewById(R.id.fieldrePassword);
        // Buttons
        findViewById(R.id.emailCreateAccountButton).setOnClickListener(this);

        // [START initialize_auth]
        // Initialize Firebase Auth
        mAuth = FirebaseAuth.getInstance();
        // [END initialize_auth]
    }

    // [START on_start_check_user]
    @Override
    public void onStart() {
        super.onStart();
        // Check if user is signed in (non-null) and update UI accordingly.
        FirebaseUser currentUser = mAuth.getCurrentUser();
        updateUI(currentUser);
    }
    // [END on_start_check_user]

    private void createAccount(String email, String password) {
        Log.d(TAG, "createAccount:" + email);
        if (!validateForm()) {
            return;
        }

        showProgressDialog();

        // [START create_user_with_email]
        mAuth.createUserWithEmailAndPassword(email, password)
                .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if (task.isSuccessful()) {
                            // Sign in success, update UI with the signed-in user's information
                            Log.d(TAG, "createUserWithEmail:success");
                            FirebaseUser user = mAuth.getCurrentUser();
                            updateUI(user);
                        } else {
                            // If sign in fails, display a message to the user.
                            Log.w(TAG, "createUserWithEmail:failure", task.getException());
                            Toast.makeText(Register.this, "createUser failed.",
                                    Toast.LENGTH_SHORT).show();
                            updateUI(null);
                        }

                        // [START_EXCLUDE]
                        hideProgressDialog();
                        // [END_EXCLUDE]
                    }
                });
        // [END create_user_with_email]
    }



    private boolean validateForm() {
        boolean valid = true;

        String email = mEmailField.getText().toString();
        if (TextUtils.isEmpty(email)) {
            mEmailField.setError("Required");
            valid = false;
        } else {
            mEmailField.setError(null);
        }

        String password = mPasswordField.getText().toString();
        if (TextUtils.isEmpty(password)) {
            mPasswordField.setError("Required");
            valid = false;
        } else {
            mPasswordField.setError(null);
        }

        return valid;
    }

    private void updateUI(FirebaseUser user) {
        hideProgressDialog();
        if (user != null) {
                    user.getEmail();
                    user.isEmailVerified();
        }
    }

    @Override
    public void onClick(View v) {
        int i = v.getId();
        if (i == R.id.emailCreateAccountButton) {
            createAccount(mEmailField.getText().toString(), mPasswordField.getText().toString());
        }
        if(i == R.id.signedInButton){
            Intent my = new Intent(this,Login.class);
            startActivity(my);
            finish();
        }

    }
}