multi language

public class MainActivity extends AppCompatActivity
{

    Button language;
    TextView phone;
    RatingBar ratingBar;
    //String languageStr = "fa";

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        final LoginShared languageStr = new LoginShared();
        if (languageStr.getLanguage() == null)
        {
            languageStr.setLanguage("fa");
        }
        super.onCreate(savedInstanceState);
        Locale locale = new Locale(languageStr.getLanguage());
        Locale.setDefault(locale);
        Configuration config = new Configuration();
        config.locale = locale;
        getBaseContext().getResources().updateConfiguration(config,
                getBaseContext().getResources().getDisplayMetrics());
        setContentView(R.layout.activity_main);

        language = findViewById(R.id.choose_language);
        phone = findViewById(R.id.telTv);
        ratingBar = findViewById(R.id.rate);
        ratingBar.setRating(3.5f);

        phone.setText("021 33333333");

        language.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View view)
            {
                PopupMenu popupMenu = new PopupMenu(MainActivity.this, language);
                //popupMenu.getMenuInflater().inflate(R.menu.menu_type_of_print, popupMenu.getMenu());

                if (languageStr.getLanguage().equals("en"))
                    popupMenu.getMenu().add(getResources().getString(R.string.persian));

                if (languageStr.getLanguage().equals("fa"))
                    popupMenu.getMenu().add(getResources().getString(R.string.english));

                popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
                    public boolean onMenuItemClick(MenuItem item) {
                        switch (item.getTitle().toString())
                        {
                            case "Persian":
                            case "فارسی":
                                languageStr.setLanguage("fa");
                                restartActivity();
                                break;
                            case "English":
                            case "انگلیسی":
                                languageStr.setLanguage("en");
                                restartActivity();
                                break;
                        }
                        return true;
                    }
                });
                popupMenu.show();
            }
        });
    }

    private void restartActivity() {
        Intent intent = new Intent(MainActivity.this , MainActivity.class);
        startActivity(intent);
        finish();
    }
}

xml

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

<androidx.constraintlayout.widget.ConstraintLayout 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">

    <ImageView
        android:id="@+id/merchant_image"
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="13dp"
        android:src="@mipmap/ic_launcher"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/nameTv"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginEnd="12dp"
        android:text="@string/name"
        android:textColor="#66000000"
        android:textSize="16sp"
        android:typeface="sans"
        app:layout_constraintStart_toEndOf="@+id/merchant_image"
        app:layout_constraintTop_toTopOf="@+id/merchant_image" />

    <RatingBar
        android:id="@+id/rate"
        style="@style/RatingBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="start"
        android:layout_marginEnd="8dp"
        android:visibility="visible"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="@+id/merchant_image" />


    <TextView
        android:id="@+id/addressTv"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="4dp"
        android:layout_marginEnd="12dp"
        android:text="@string/address"
        android:textColor="#acacac"
        android:textSize="14sp"
        android:typeface="sans"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="@+id/nameTv"
        app:layout_constraintTop_toBottomOf="@+id/nameTv" />

    <View
        android:id="@+id/view3"
        android:layout_width="0dp"
        android:layout_height="1dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="8dp"
        android:background="@color/dash_color"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/addressTv" />

    <ImageView
        android:id="@+id/imageView20"
        android:layout_width="15dp"
        android:layout_height="15dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="8dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/view3"
        app:srcCompat="@drawable/ic_local_phone_24dp" />

    <TextView
        android:id="@+id/telTv"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:textColor="#acacac"
        android:visibility="visible"
        app:layout_constraintBottom_toBottomOf="@id/imageView20"
        app:layout_constraintStart_toEndOf="@id/imageView20"
        app:layout_constraintTop_toTopOf="@id/imageView20"
        tools:text="@string/phone" />

    <Button
        android:id="@+id/choose_language"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp"
        android:text="@string/choose_language"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/imageView20" />
</androidx.constraintlayout.widget.ConstraintLayout>