Q:What is the life cycle of a started service?
Ans : oncreate -> onstartCommand() -> onDestroy()
Q:Activity life cycle: What to do in onRestart() of an activity?
Ans: if any UI changes happened while it is in invisible state, updated it in this function.
Q:What is the difference between implicit intent and explicit intent, give one example?
Ans : Implicit intent - Intent with out target component name; Explicit intent - Intent with target component name.
Q:What will happen if an activity is started with implicit intent, and there is no matching intent-filter?
Ans : it will throw run time exception - activityNotFoundException, and crashes if it is not handled properly.
Q:How to kill an activity?
Ans: i. finish() ii. finishActivity(int requestcode).
Q:How to get the phone's location when battery is draining out? which feature is preferable to use to fetch my current location?
Ans : either use network provider with WiFi disabled or use lastKnownLocation.
Q:Give two examples for configuration changes in Android?
Ans : flipping the phone,keyboard on,language settings change
Q:What is the package name of JSONObject, JSONArray?
Ans: org.json
Q:What is the difference between service and a thread?
Ans : Service - is a component of android, which runs in the background with out any UI. By default service will run in Main thread only. Thread - is not android component, but still one can use thread to do some background task. Using thread in place of service is discouraged.
Q:can I start a service from worker thread?
Ans : You can start service from any where, but still oncreate, onstartcommand runs in main thread only.
Q:How to get current location in android?
Ans : i. Use either GPS location provider or Network location provider to fetch the current location of a phone, in terms of latitude and longitude. ii. Use LocationManager class, and LocationListener class to fetch locations. Use requestLocationUpdates to register locationlistener with locationmanager object. iii. When ever location gets changed, location manager will automatically call onLocationChanged() method of locationlistner. iv. Use ACCESS_FINE_LOCATION and ACCESS_COARSE_LOCATION permissions in the manifest file.
Q:Broadcast receiver runs in which thread, by default?
Ans: Main Thread
Q:Is it possible to start a service from a broadcast receiver?
Ans: yes can start using startService() function
Q:If I want to use MapView, what all the steps I have to follow?
Ans: Use MapActivity with MapView and use library "com.google.android.maps". App should have internet permission as well, we have to register our application with Google maps service, by providing md5 finger print of the debug certificate of the application.
Q:If internet permission is not taken to use HTTP Client, then what will happen?
Ans: It will throw run time exception, i.e IOException
Q:What will happen if super.oncreate() from oncreate() function of activity is commented?
Ans : Run time exception, super not called.
Q:What is the purpose of SQLiteOpenHelper?
Ans : A helper class to manage database creation,upgrading and version management with out loosing state of the previous data.
Q:What does httpclient.execute() return?
Ans: HttpResponse
Q:What is the life cycle of a Fragment?
Ans: onAttach() onCreate() onCreateView() onActivityCreated() onStart() onResume().
Q:Which sensor is used to find gravitational force on each axes (x,y, &z)?
Ans: Accelerometer
Q:How to find whether GPS is disabled in the phone?
Ans: if it is disabled onProviderDisabled() will be called with provider name.
Q:what is the permission required to make a call in android, by using ACTION_CALL ?
Ans: android.permission.CALL_PHONE
Q:How to share preference file to other activities of same application?
Ans: Use getSharedPreferences("name", MODE_PRIVATE);
Q:What is the purpose of the ContentProvider class?
Ans: To share data between Android applications.
