2.1 Android User Interface2.2 Layouts2.3 The View Class2.4 Text Input and Output2.5 Soft Keyboards2.6 Android’s Form Widgets for User Interfaces2.6.1 RadioButton and CheckBox2.6.2 ToggleButton2.6.3 Switch2.6.4 ProgressBar2.6.5 SeekBar2.6.6 RatingBar2.6.7 Spinner2.7 Unique ID of a View Object and the R Class2.8 The ViewGroup2.8.1 RadioGroup2.9 Adaptive Design Concepts—Screens and Orientations2.10 TableLayout and TableRow2.11 Container Views2.11.1 ListView, GridView, and ExpandableListView2.11.2 ScrollView and HorizontalScrollView2.11.3 SearchView2.11.4 VideoView2.12 Using an AdapterExercises