1.1.3 Getting started_budding Your First app_building a simple User Interface

The graphical user interface for an Android app was built using a hierarchy of View and ViewGroup objects. View Objects is U Sually UI widgets such as buttons or text fields and ViewGroup objects is invisible view containers that define what the child Views is laid out, such as in a grid or a vertical list.

Android provides an XML vocabulary this corresponds to the subclasses of and so you View ViewGroup can define your UI in XML Using a hierarchy of UI elements.

The Android user interface is created using the hierarchy of View and ViewGroup. View is the usual UI widgets (gadget), such as the Buttons,text Fields,viewgroup is an invisible view container that defines the layout of the included view, such as a grid or vertical list.

Android provides an XML syntax that corresponds to View and viewgroup, so you can use hierarchical UI elements in XML to define your UI