General concepts

 Android

The General important components are
1.Activity

2.Perform long running operations in the background,
do not have a user interface,
useful for things like network operation , music ect
it runs independetly of the component that created it
it can be bounded to by other application components if allowed

3.Content Providers
 Used to store and retrieve data and make it accessible to all apps
 only way to share data across application
 Exposes a public uri that uniquely identifies its data set
 Android Contains many providers for things like contacts , media etc

4.Broadcast Announcements
A component that responds to System wide broadcast announcements
examply when screen turns off , the battery is low
Application can also initialte their own breadcast
It has no UI
They can create a status bar notification to alert the user

5.Android Manifest File
Presents information about the application to the Android System.
Describes the components used in the application
Describle the permissions required to run the application
Declares the minimun Android Api level that the application requires



Android manifest
Its the activity->Intent-filter->action that tell the manifest which screen is launched first
the value is <action android:name="android.intent.action.MAIN"