The document discusses the fundamentals of Android mobile app development, focusing on utilizing the action bar, creating user interfaces programmatically, and handling UI notifications. It outlines methods for adding action items and interacting with the UI at both activity and view levels, providing examples of overriding methods for user interaction. The document also emphasizes practical steps like creating XML files for action bars and menus, and registering events for views to execute user commands.

1. Android Mobile App
Development
Lecture :
UTILIZING THE ACTION BAR Managing
CREATING THE USER INTERFACE
PROGRAMMATICALLY
LISTENING FOR UI NOTIFICATIONS

2. UTILIZING THE ACTION BAR Managing

3. how you can programmatically hide or
display the Action Bar

4. Programmatically remove the Action Bar using the
ActionBar class
 First need to remove the android:theme attribute you added in the
Manifest file.

5. Adding Action Items to the Action Bar
 Besides displaying the application icon and the activity title on the left of
the Action Bar, you can also display additional items on the Action Bar.
These additional items are called action items.
 Action items are shortcuts to some of the commonly performed operations
in your application.
 For example, you might be building an RSS reader application, in which
case some of the action items might be “Refresh feed,” “Delete feed” and
“Add new feed.”

6. Method1:
 Create new project
 Create an actionbar.xml file ( for designing of action bar)

8.  Add actionbar.xml to activity_main.xml
 Now access widgets of action bar in java file and apply clickListener
on it.

10. Method 2
 Create new project
 Create Menu directory and also menu file in it and add items in menu.xml
file.

11.  Read menu file in MainActivity.class

12. Output

13. CREATING THE USER INTERFACE
PROGRAMMATICALLY

14. CREATING THE USER INTERFACE
PROGRAMMATICALLY
 Created a LayoutParams object to specify the layout parameter that can
be used by other views.
 LinearLayout object to contain all the views in your activity

15. LISTENING FOR UI NOTIFICATIONS
Users interact with your UI at two levels:
 activity level
 View level
At the activity level, the Activity class exposes methods that you can override. Some
common methods that you can override in your activities include the following:
➤ onKeyDown — Called when a key was pressed and not handled by any of the
views contained within the activity
➤ onKeyUp — Called when a key was released and not handled by any of the views
contained within the activity
➤ onMenuItemSelected — Called when a panel’s menu item has been selected by
the user
➤ onMenuOpened — Called when a panel’s menu is opened by the user

16. Overriding Methods Defined in an
Activity
 When the activity is loaded, type some text into the EditText. Next, click the
down arrow key on the directional pad. Observe the message shown on
the screen

18. Registering Events for Views
 For example, when a user touches a Button view, you need to service the
event so that the appropriate action can be performed.

19.  If you now click either the OK button or the Cancel button, the appropriate
message will be displayed , proving that the event is wired up properly