Construct a layout using XML or Java code (Associate Android Developer Certification)

Adding TextView in XML:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:paddingBottom="@dimen/activity_vertical_margin"
   android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   android:orientation="vertical"
   android:id="@+id/root"
   tools:context="com.gayratrakhimov.uiuxsandbox.MainActivity">

    <TextView
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:text="Hello World!" />

</LinearLayout>

In code:

public class MainActivity extends AppCompatActivity {

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

        LinearLayout root = (LinearLayout) findViewById(R.id.root);

        TextView textView = new TextView(this);
        textView.setText("Hello Android!");
        root.addView(textView);

    }
   
}