ANDROID INTERVIEW TOUGH QUESTIONS

ANDROID INTERVIEW TOUGH QUESTIONS 

Remember that the GUI layer doesn't request data directly from the web; data is always loaded from a local database.

The service layer periodically updates the local database.

What is the risk in blocking the Main thread when performing a lengthy operation such as web access or heavy computation? Application_Not_Responding exception will be thrown which will crash and restart the application.

Why is List View not recommended to have active components? Clicking on the active text box will pop up the software keyboard but this will resize the list, removing focus from the clicked element.

For senior employees

Beyond a certain level of experience, the job interview questions cease to be "difference between abstract class and interface", and focus more on testing your technical acumen, collaboration and communication skills. A list of such questions, typically asked during interviews for senior positions is given below:

Explain the life cycle of an application development process you worked on previously.

What the interviewer looks for is communication of requirements, planning, modeling, construction and deployment on the back end.

Here's a hypothetical project. Explain how you would go about it.

They want to know how you would break your work down into tasks and how many weeks for each task. I'm really looking to find out about planning methods, their skill set and how quickly they can execute.

How do you respond to requirement changes in the middle of a cycle?

What type of methodology have you used in the past? What are its drawbacks?

What are different techniques for prototyping an application?

Similar question: Do you feel there is value in wireframing an application? Why?

How do you manage conflicts in Web applications when there are different people managing data?

Tell me something you learned from a team member in the last year.

What software testing procedures have you used to perform a QA?

Once the coding skills verified. Sample I

· The Activity life cycle is must. Ask about the different phases of Activity Life cycle. For example: when and how the activity comes to foreground?

· Check the knowledge on AndroidManifest file, For example: Why do we need this file, What is the role of this file in Android app development.

· Different Kinds of Intents

· Ask about different Kinds of context

· Ask about different Storage Methods in android

· Kinds of Log debugger and Debugger Configuration

· How to debug the application on real device.

· How do you ensure that the app design will be consistent across the different screen resolutions

· Thread concepts also plus points as we deal with the treads more.

· Can you able to build custom views and how?

· How to create flexible layouts, For example to place English, Chinese fonts.

· What is localization and how to achieve?

· What are 9-patch images

· How to avoid ANR status

· How to do Memory management

· Ask about IPC

· What is onCreate(Bundle savedInstanceState), Have you used savedInstanceState when and why?

· To check how updated the person is just ask about what are Fragments in an Activity

If this is an Android specific job, just ask the obvious stuff. Sample II

Application lifecycle

When to use a service

How to use a broadcast receiver and register it both in the manifest and in code

Intent filters

Stuff about what manifest attributes and tags mean

The types of flags to run an application

FLAG_ACTIVITY_NEW_TASK

FLAG_ACTIVITY_CLEAR_TOP

etc

How to do data intensive calculations using threads

Passing large objects (that can't be passed via intents and shouldn't be serialized) via a service

Binding to a service and the service lifecycle

How to persist data (both savedInstanceState and more permanent ways)

Just go through http://developer.android.com/guide/topics/fundamentals.html and see what sounds like it's important. Hopefully you're an android developer and know what all those things are, otherwise you're just waiting your interviewee's time =P

Android get current GPS location

You can Find location either GPS_PROVIDER or NETWORK_PROVIDER

Overview of location services in Android , LocationManager class at the heart of location services in Android.

Here is one example which try to find location using GPS , if your GPS not available then try to use network for find location

Demo Code

Activity - AndroidGPSTrackingActivity.java

public class AndroidGPSTrackingActivity extends Activity {
  
    Button btnShowLocation;
  
    // GPSTracker class
    GPSTracker gps;
  
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
      
        btnShowLocation = (Button) findViewById(R.id.btnShowLocation);
      
        // show location button click event
        btnShowLocation.setOnClickListener(new View.OnClickListener() {
          
            @Override
            public void onClick(View arg0) {      
                // create class object
                gps = new GPSTracker(AndroidGPSTrackingActivity.this);

                // check if GPS enabled      
                if(gps.canGetLocation()){
                  
                    double latitude = gps.getLatitude();
                    double longitude = gps.getLongitude();
                  
                    // \n is for new line
                    Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();  
                }else{
                    // can't get location
                    // GPS or Network is not enabled
                    // Ask user to enable GPS/network in settings
                    gps.showSettingsAlert();
                }
              
            }
        });
    }
  
}

GPSTracke.java

public class GPSTracker extends Service implements LocationListener {

    private final Context mContext;

    // flag for GPS status
    boolean isGPSEnabled = false;

    // flag for network status
    boolean isNetworkEnabled = false;

    // flag for GPS status
    boolean canGetLocation = false;

    Location location; // location
    double latitude; // latitude
    double longitude; // longitude

    // The minimum distance to change Updates in meters
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters

    // The minimum time between updates in milliseconds
    private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute

    // Declaring a Location Manager
    protected LocationManager locationManager;

    public GPSTracker(Context context) {
        this.mContext = context;
        getLocation();
    }

    public Location getLocation() {
        try {
            locationManager = (LocationManager) mContext
                    .getSystemService(LOCATION_SERVICE);

            // getting GPS status
            isGPSEnabled = locationManager
                    .isProviderEnabled(LocationManager.GPS_PROVIDER);

            // getting network status
            isNetworkEnabled = locationManager
                    .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

            if (!isGPSEnabled && !isNetworkEnabled) {
                // no network provider is enabled
            } else {
                this.canGetLocation = true;
                if (isNetworkEnabled) {
                    locationManager.requestLocationUpdates(
                            LocationManager.NETWORK_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                    Log.d("Network", "Network");
                    if (locationManager != null) {
                        location = locationManager
                                .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                        if (location != null) {
                            latitude = location.getLatitude();
                            longitude = location.getLongitude();
                        }
                    }
                }
                // if GPS Enabled get lat/long using GPS Services
                if (isGPSEnabled) {
                    if (location == null) {
                        locationManager.requestLocationUpdates(
                                LocationManager.GPS_PROVIDER,
                                MIN_TIME_BW_UPDATES,
                                MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                        Log.d("GPS Enabled", "GPS Enabled");
                        if (locationManager != null) {
                            location = locationManager
                                    .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                            if (location != null) {
                                latitude = location.getLatitude();
                                longitude = location.getLongitude();
                            }
                        }
                    }
                }
            }

        } catch (Exception e) {
            e.printStackTrace();
        }

        return location;
    }
  
    /**
     * Stop using GPS listener
     * Calling this function will stop using GPS in your app
     * */
    public void stopUsingGPS(){
        if(locationManager != null){
            locationManager.removeUpdates(GPSTracker.this);
        }      
    }
  
    /**
     * Function to get latitude
     * */
    public double getLatitude(){
        if(location != null){
            latitude = location.getLatitude();
        }
      
        // return latitude
        return latitude;
    }
  
    /**
     * Function to get longitude
     * */
    public double getLongitude(){
        if(location != null){
            longitude = location.getLongitude();
        }
      
        // return longitude
        return longitude;
    }
  
    /**
     * Function to check GPS/wifi enabled
     * @return boolean
     * */
    public boolean canGetLocation() {
        return this.canGetLocation;
    }
  
    /**
     * Function to show settings alert dialog
     * On pressing Settings button will lauch Settings Options
     * */
    public void showSettingsAlert(){
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
       
        // Setting Dialog Title
        alertDialog.setTitle("GPS is settings");

        // Setting Dialog Message
        alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");

        // On pressing Settings button
        alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog,int which) {
                Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                mContext.startActivity(intent);
            }
        });

        // on pressing cancel button
        alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
            dialog.cancel();
            }
        });

        // Showing Alert Message
        alertDialog.show();
    }

    @Override
    public void onLocationChanged(Location location) {
    }

    @Override
    public void onProviderDisabled(String provider) {
    }

    @Override
    public void onProviderEnabled(String provider) {
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
    }

    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

}

Layout - main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
   
    <Button android:id="@+id/btnShowLocation"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Show Location"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"/>

</RelativeLayout>

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />  
    <uses-permission android:name="android.permission.INTERNET" />

Android Interview Questions and Answer

1. Define Android?

Android is software stack for mobile devices that has middleware, operating system and specific key applications. The application must be implemented in its own process and Dalvik Virtual Machine interface. DVM device is used to effectively run several virtual machines. The byte code of java language is executed by DVM that is converted to .dex format files.

2. Define Activity?
Activity is nothing but application’s single screen that assists java code.

3. Define intent?
Intent is a class that depicts what caller has to do. Intent is send to intent resolver of Android by the caller which finds appropriate activity for intent. For example: intent is opening PDF doc and the perfect activity for intent is apps of Adobe Reader.

4. Define resource?
Resource is nothing but user defined XML, JSON or bitmap that is inserted in application build process which is later loaded from code.

5. Does Android assist profile of Bluetooth serial port?
Yes



 

6. Is it possible to start an application on powerup?
  Yes


7. Define APK format?
APK file is compacted AndroidManifest.xml file that has .apk extension. Resource files, Application code and many other files are present in this format and are compressed to single file which has .apk extension.

8. Explain translation in Android?
The data of one language can be changed to other language by Google translator by making use of XMPP for data transmission. You can type English message and choose the language that is easily understood by your country people to reach message to them.

9. On which virtual machine Android runs?
Dalvik virtual machine

10. What is the latest version in android?
Android 4.2(Jelly Bean)

12. Give the new Android platform for mobile phones?
Android 4.0 and the name given to this version is Ice-cream Sandwich. The versions that came before this are given below:
• 3. X.X Honeycomb
• 2.3. X Gingerbread
• 2.2 Froyo
• 2.0/2.1 Éclair
• 1.6 Donut
• 1.5 Cupcake

13. Give the languages that are supported by Android operating system for developing applications?
It supports all the languages that are written using java code.


14. In what ways data can be stored in Android?
• Internal storage
• Network connection
• Shared preferences
• Sqlite database
• External storage

15. What are user interface types?
• Notifications
• Views


16. Give notification types in Android?
• Dialog notification
• Status bar notification
• Tost notification

Android Upload Video in server

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text=""

    android:id="@+id/tv"

    />
    <TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello"
    />
<Button android:text="Browse gallery"
    android:id="@+id/Button01"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">
</Button>
<ImageView android:id="@+id/ImageView01"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">
</ImageView>
</LinearLayout>

uploadfile.java

public class uploadfile extends Activity {
    TextView tv = null;
   
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        tv = (TextView) findViewById(R.id.tv);
        doFileUpload();
    }
   
    private void doFileUpload(){

          HttpURLConnection conn = null;
          DataOutputStream dos = null;
          DataInputStream inStream = null;

       
          String exsistingFileName = "/sdcard/six.3gp";
          // Is this the place are you doing something wrong.

          String lineEnd = "\r\n";
          String twoHyphens = "--";
          String boundary =  "*****";


          int bytesRead, bytesAvailable, bufferSize;

          byte[] buffer;

          int maxBufferSize = 1*1024*1024;
 
          String urlString = "http://192.168.1.5/upload.php";
         
         
         
          try
          {
          
       
          Log.e("MediaPlayer","Inside second Method");

          FileInputStream fileInputStream = new FileInputStream(new File(exsistingFileName) );



           URL url = new URL(urlString);

           conn = (HttpURLConnection) url.openConnection();

           conn.setDoInput(true);

           // Allow Outputs
           conn.setDoOutput(true);

           // Don't use a cached copy.
           conn.setUseCaches(false);

           // Use a post method.
           conn.setRequestMethod("POST");

           conn.setRequestProperty("Connection", "Keep-Alive");
       
           conn.setRequestProperty("Content-Type", "multipart/form-data;boundary="+boundary);

          
           dos = new DataOutputStream( conn.getOutputStream() );

           dos.writeBytes(twoHyphens + boundary + lineEnd);
           dos.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\";filename=\"" + exsistingFileName +"\"" + lineEnd);
           dos.writeBytes(lineEnd);

           Log.e("MediaPlayer","Headers are written");



           bytesAvailable = fileInputStream.available();
           bufferSize = Math.min(bytesAvailable, maxBufferSize);
           buffer = new byte[bufferSize];



           bytesRead = fileInputStream.read(buffer, 0, bufferSize);

           while (bytesRead > 0)
           {
            dos.write(buffer, 0, bufferSize);
            bytesAvailable = fileInputStream.available();
            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            bytesRead = fileInputStream.read(buffer, 0, bufferSize);
           }

          

           dos.writeBytes(lineEnd);
          
           dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

           BufferedReader in = new BufferedReader(
                           new InputStreamReader(
                           conn.getInputStream()));
                String inputLine;
               
                while ((inputLine = in.readLine()) != null)
                    tv.append(inputLine);

          
          
          
           // close streams
           Log.e("MediaPlayer","File is written");
           fileInputStream.close();
           dos.flush();
           dos.close();


          }
          catch (MalformedURLException ex)
          {
               Log.e("MediaPlayer", "error: " + ex.getMessage(), ex);
          }

          catch (IOException ioe)
          {
               Log.e("MediaPlayer", "error: " + ioe.getMessage(), ioe);
          }


          //------------------ read the SERVER RESPONSE


          try {
                inStream = new DataInputStream ( conn.getInputStream() );
                String str;
              
                while (( str = inStream.readLine()) != null)
                {
                     Log.e("MediaPlayer","Server Response"+str);
                }
                /*while((str = inStream.readLine()) !=null ){
                   
                }*/
                inStream.close();

          }
          catch (IOException ioex){
               Log.e("MediaPlayer", "error: " + ioex.getMessage(), ioex);
          }
         
         

        }
}

AndroidManifest.xml

<uses-permission android:name="android.permission.INTERNET" />

upload.php

<?php

move_uploaded_file($_FILES['uploadedfile']['tmp_name'], "./".$_FILES["uploadedfile"]["name"]);

?>