Brush-Up Android Concepts Before Interview - Part 1

by Unknown Tuesday, December 30, 2014 0 comments Android interview for experience Android QA Android Tutorial

Android Application Architecture:

Android Application Architecture has following components such as

Services, Intent, Resources Externalization, Notification signaling users, Content providers

Dalvik Virtual Machine

It is optimizes the JVM for memory,battery,performance. It optimized for mobile devices.

Activities

An activity represents a single screen with user interface.

 public void MyActivity extends Activity{  
 }  

Service
Service is like an Activity but has no interface. It is component that runs in background for long running process eg: music player
Types:

• Unbound Services 
• It runs in the background indefinitely, even if the activity which started this  service ends.
• Bound Services
• It runs till lifespan of the activity which started this service. Client-Server interface.

 public void MyService extends Service{  
 }  
 <service android:name=”.MyService”/>  

Intent
Describing specific action. 
Types:

• Implicit Intent
• It redirect from Activity in application to external application activity.

 Uri uri = Uri.parse(“http://www.google.com”);  
 Intent i = new Intent(Intent.ACTION_VIEW,uri);  
 startActivity(i);  

• Explicit Intent
• It redirect from Activity to another Activity in application.

 Intent i = new Intent(this,SecondActivity.class);  
 startActivity(i);  

BroadcastReceiver
It simply respond to broadcast messages from other applications or from the system.

 public class MyReceiver extends BroadcastReceiver{  
 public void onReceive(Context context,Intent intent){}  
 }  

Content Providers
A content provider component supplies data from one application to others on request.