Component- 3.Broadcast Receivers

Broadcast Receivers
  • A broadcast/Intent receiver is a component that receives and reacts to broadcast announcements.    
  • Applications can also initiate broadcasts
                  Example: to let the other applications know that some data has been downloaded and is available for them to use
  • They also respond to a system-wide announcement of an event
  • Announcements can come :   internally, say from OS – Battery Low / timezone change or from other applications.
  • Broadcast receiver components are used to listen to the announcements made by other application components through intents.
  •  Broadcast receivers can respond to the announcements in following ways:
  1.  Starting an activity
  2. Starting a service
  3. Alert using notifications
  •  Broadcast receivers does not have any user interface.
  • They also respond to a system-wide announcement of an event
  • Announcements can come as
                  internally, say from OS – Battery Low / timezone change or from other applications
 There are two major classes of broadcasts that can be received:
  • Normal broadcasts (sent with Context.sendBroadcast) are completely asynchronous. All receivers of the broadcast are run in an undefined order, often at the same time. This is more efficient, but means that receivers cannot use the result or abort APIs included here.
  • Ordered broadcasts (sent with Context.sendOrderedBroadcast) are delivered to one receiver at a time. As each receiver executes in turn, it can propagate a result to the next receiver, or it can completely abort the broadcast so that it won't be passed to other receivers. The order receivers run in can be controlled with the android:priority attribute of the matching intent-filter; receivers with the same priority will be run in an arbitrary order.

Comments

Post a Comment

Please post comments here:-)

Popular posts from this blog

Android Objective type Question and Answers

Android Objective type Question and Answers 1) Once installed on a device, each Android application lives in_______?  a)device memory  b)external memory  c) security sandbox  d)None of the above Ans) c 2)Parent class of Activity?  a)Object  b)Context  c)ActivityGroup  d)ContextThemeWrapper Ans) d 3)What are the Direct subclasses of Activity?  a)AccountAuthenticatorActivity  b) ActivityGroup  c) ExpandableListActivity  d) FragmentActivity  e) ListActivity  f) all the aove Ans) f 4)What are the indirect Direct subclasses of Activity?  a)LauncherActivity  b)PreferenceActivity  c) TabActivity  d)All the above Ans) d 5)Parent class of Service?  a)Object  b)Context  c) ContextWrapper  d)ContextThemeWrapper Ans) c 6)What are the indirect Direct subclasses of Services?  a) RecognitionService  b) RemoteViewsService  c)SpellCheckerS...
Read more

Android Questions and Answers for written exams

1. bmgr tool is used to a)take backup of the applications b)to restore operations c)wipe archived data for a specific application d)all of the above ans: d 2. foreground service a)starts when you call start foreground() b)may or may not provide a notification for the status bar c)notification can't be dismissed unless the service is either stopped or removed from the foreground d)both a & c ans:d 3. A1,A2,A3 and A4 are activities called using intents.Then A1-A4-A2--A3.A4 calls A2 with intent flag FLAG_ACTIVITY_NO_HISTORY.When finish method is called on A3, What will be the currtent running activity? a)A1 b)A4 c)A3 d)A2 ans: b 4. A1,A2,A3 and A4 are activities called using intents.Then A1-A2-A4--A3.A2 calls A4 with intent flag FLAG_ACTIVITY_CLEAR_TOP.When finish() method is called on A3, what will be the current running activity? a)A4 b)A3 c)A2 d)A1 Ans:  a 5. A1,A2,A3 and A4 are activities called using intents.Then A1-A2-A3-A4. A3 call...
Read more

SCJP1.6 Question and Answers

Question – 1 What is the output for the below code ? 1.         public class A { 2.         int add(int i, int j){ 3.                     return i+j; 4.                     } 5.         } 6.         public class B extends A{ 7.         public static void main(String argv[]){ 8.         short s = 9; 9.         System.out.println(add(s,6)); 10.        } 11.        } Options are A. Compile fail due to error on line no 2 B. Compile fail due to error on lin...
Read more