MainActivity

public class MainActivity extends AppCompatActivity {

    private FontChecker fontChecker = FontChecker.getInstance();
    private TextView lblFontInfo;

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

        lblFontInfo = findViewById(R.id.lblFontInfo);

        if (fontChecker.isUnicode(getApplicationContext())) {
            lblFontInfo.setText("This device use unicode.");
        } else {
            lblFontInfo.setText("This device use zawgyi.");
        }
    }
}

//Xml Layout-> activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/lblFontInfo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:fontFamily="sans-serif"
        android:textAppearance="@style/Base.TextAppearance.AppCompat.Large"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>