1. Components
   1. Activitie
      1. Presents a single visual user interface
      2. each activity is indepentdent of the others
      3. one of the activities is marked as the first
      4. intents
   2. Service
   3. Broadcast receiver
   4. Content Provider
2. User Interface
   1. View Class
      1. represent the basic bulding block for UI component
      2. A view occupies arectangular area on the screen and is responsible for drawing and event handling
      3. base class for widgets
      4. Group view
         1. Xml Layouts
            1. LinearLayout
            2. is a box model
            3. are lined up in a column or row
            4. areas of control
            5. orientation
            6. fill model
            7. weight
            8. gravity
            9. padding
            10. margin
            11. RelativeLayout
            12. TableLayout
            13. ScrollView
            14. AbsoluteLayout
            15. Each element in XML layout is either a view or groupView
         2. is the base class for layouts
   2. Menus
      1. Increase the functionality of an app
      2. 2 types
         1. option menu
         2. context menu
      3. Observation
         1. text
         2. Icons
         3. Radio Buttons
         4. Checkboxs
         5. Sub-Menus
         6. Short-cut Keys
      4. using
         1. step1
            1. Indicate which widget(s) on your activity have contextMenu
         2. step2
            1. Implement onCreateContextMenu(...)
            2. onCreateContextMenu() is called each time the context menu is requested
            3. context menus are discarded once they are used or dismissed
            4. onContextItemSelected()
            5. delegate on the applyMenuChoice() Method the performing of the actions associated to the choices made by user
   3. Widgets
3. Life cycle
   1. Components lifecycle
      1. A beginning when android instantiates them response to intents
      2. A end when the instances are destroyed
      3. In between they somtimes be active / inactive ,visible/invisible
   2. Activity Stack
   3. States
   4. Event
4. Project
   1. YourActivity.java
   2. R.java
   3. Android Library/
   4. assets/
   5. res/
   6. res/drawable
   7. res/layout
   8. res/values
   9. AndroidManifest.xml
5. Main Topic 5