Android activities 1 CS300

What makes an app?  Activities: presentation layer  Services: invisible workers  Content Providers: databases  Intents: message-passing framework  Broadcast receivers: broadcast consumers  Widgets: components added to home screen  Notifications: signa users without interrupting their current activities CS300 2

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Activity states  Foreground of the screen: active or running.  At top of stack  Lost focus but still visible: paused.  A paused activity is completely alive, but can be killed by the system in extreme low memory situations.  Completely obscured by another activity: stopped.  Retains all state and member information, however, it is no longer visible to the user  If paused or stopped, the system can drop the activity from memory by either asking it to finish, or simply killing its process. CS300 4

Configuration changes  It will cause your current activity to be destroyed going through the normal activity lifecycle process of onPause(), onStop(), and onDestroy() as appropriate.onPause()onStop()onDestroy()  If the activity had been in the foreground or visible to the user, once onDestroy() is called in that instance then a new instance of the activity will be created, with whatever savedInstanceState the previous instance had generated from onSaveInstanceState(Bundle).onDestroy()onSaveInstanceState(Bundle) CS300 5

AndroidManifest.xml  heart of the (structure of) android app  lists out all the modules of your android application CS300 6

What does the manifest do??  Identify any user permissions the application requires, such as Internet access or read-access to the user's contacts.  Declare the minimum API Level required by the application, based on which APIs the application uses.API Level  Declare hardware and software features used or required by the application, such as a camera, bluetooth services, or a multitouch screen.  API libraries the application needs to be linked against (other than the Android framework APIs), such as theGoogle Maps library.Google Maps library 7

What does the manifest do??  The primary task of the manifest is to inform the system about the application's components  You must declare all application components this way:  elements for activities  elements for services  elements for broadcast receivers  elements for content providers CS300 8

Resources  app/Activity.html app/Activity.html  undamentals.html undamentals.html  st/manifest-intro.html st/manifest-intro.html CS300 9