How to store mac address - android-studio

Question

I'm writing an App with login and register, it works but I want to add something. Is it possible, when a user register his datas, to get directly from his phone the Mac Address and store it together the other datas?
For example, he has to insert name, user, password and email, when he clicks on register in the database there are all this datas and the macaddress of his phone too.
This is my RegisterActivity.java:
import android.os.Bundle;
import android.os.Handler;
import android.support.annotation.Nullable;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TextInputLayout;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
/**
* Created by amardeep on 10/26/2017.
*/
public class RegisterActivity extends AppCompatActivity {
//Declaration EditTexts
EditText editTextUserName;
EditText editTextEmail;
EditText editTextPassword;
//Declaration TextInputLayout
TextInputLayout textInputLayoutUserName;
TextInputLayout textInputLayoutEmail;
TextInputLayout textInputLayoutPassword;
//Declaration Button
Button buttonRegister;
//Declaration SqliteHelper
SqliteHelper sqliteHelper;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
sqliteHelper = new SqliteHelper(this);
initTextViewLogin();
initViews();
buttonRegister.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (validate()) {
String UserName = editTextUserName.getText().toString();
String Email = editTextEmail.getText().toString();
String Password = editTextPassword.getText().toString();
//Check in the database is there any user associated with this email
if (!sqliteHelper.isEmailExists(Email)) {
//Email does not exist now add new user to database
sqliteHelper.addUser(new User(null, UserName, Email, Password));
Snackbar.make(buttonRegister, "User created successfully! Please Login ", Snackbar.LENGTH_LONG).show();
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
finish();
}
}, Snackbar.LENGTH_LONG);
}else {
//Email exists with email input provided so show error user already exist
Snackbar.make(buttonRegister, "User already exists with same email ", Snackbar.LENGTH_LONG).show();
}
}
}
});
}
//this method used to set Login TextView click event
private void initTextViewLogin() {
TextView textViewLogin = (TextView) findViewById(R.id.textViewLogin);
textViewLogin.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
finish();
}
});
}
//this method is used to connect XML views to its Objects
private void initViews() {
editTextEmail = (EditText) findViewById(R.id.editTextEmail);
editTextPassword = (EditText) findViewById(R.id.editTextPassword);
editTextUserName = (EditText) findViewById(R.id.editTextUserName);
textInputLayoutEmail = (TextInputLayout) findViewById(R.id.textInputLayoutEmail);
textInputLayoutPassword = (TextInputLayout) findViewById(R.id.textInputLayoutPassword);
textInputLayoutUserName = (TextInputLayout) findViewById(R.id.textInputLayoutUserName);
buttonRegister = (Button) findViewById(R.id.buttonRegister);
}
//This method is used to validate input given by user
public boolean validate() {
boolean valid = false;
//Get values from EditText fields
String UserName = editTextUserName.getText().toString();
String Email = editTextEmail.getText().toString();
String Password = editTextPassword.getText().toString();
//Handling validation for UserName field
if (UserName.isEmpty()) {
valid = false;
textInputLayoutUserName.setError("Please enter valid username!");
} else {
if (UserName.length() > 5) {
valid = true;
textInputLayoutUserName.setError(null);
} else {
valid = false;
textInputLayoutUserName.setError("Username is to short!");
}
}
//Handling validation for Email field
if (!android.util.Patterns.EMAIL_ADDRESS.matcher(Email).matches()) {
valid = false;
textInputLayoutEmail.setError("Please enter valid email!");
} else {
valid = true;
textInputLayoutEmail.setError(null);
}
//Handling validation for Password field
if (Password.isEmpty()) {
valid = false;
textInputLayoutPassword.setError("Please enter valid password!");
} else {
if (Password.length() > 5) {
valid = true;
textInputLayoutPassword.setError(null);
} else {
valid = false;
textInputLayoutPassword.setError("Password is to short!");
}
}
return valid;
}
}
Thank you very much!