2.4.6. The Default GUI

The default GUI (Fig. 2.12) for a Blank Page app consists of a RelativeLayout with a light-gray background (specified by the theme we chose when creating the project) and a TextView containing "Hello world!". A RelativeLayout arranges GUI components relative to one another or relative to the layout itself—for example, you can specify that a GUI component should appear below another GUI component and centered horizontally within the RelativeLayout. A TextView displays text. We’ll say more about each of these in Section 2.5.