Activating App Components (Intent)

App component are activated by an asynchronous message called an intent. Intents bind individual components to each other at run-time. 

Intent 

 Intent is a message to activate a component, it is created with an Intent object. —an intent can be either explicit or implicit, respectively. There are separate methods for activating each type of component:

           i. You can start an activity (or give it something new to do) by passing an Intent to startActivity() or startActivityForResult() (when you want the activity to return a result).
           ii. You can start a service (or give new instructions to an ongoing service) by passing an Intent to startService(). Or you can bind to the service by passing an Inten to bindService().
           iii. You can initiate a broadcast by passing an Inten to methods like sendBroadcast(), sendOrderedBroadcast(), or sendStickyBroadcast().
           iv.  You can perform a query to a content provider by calling query() on a ContentResolver.
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