Katharnavas Tech Blog

Listening for outgoing sms or send sms in Android

katharnavas — Wed, 18 Jan 2012 13:48:48 +0000

The following code shows how to register and event and observe changes made to the sms folder for send sms.
Most of the people states that the code may not work in future versions. Currently it works pretty with 2.1 and 2.2 and 2.3

public class SmsObserver extends ContentObserver {
	
    private Context mContext;
    
    private String contactId = "", contactName = "";
    private String smsBodyStr = "", phoneNoStr = "";
    private long smsDatTime = System.currentTimeMillis();
    static final Uri SMS_STATUS_URI = Uri.parse("content://sms");
    
	public SmsObserver(Handler handler, Context ctx) {
		super(handler);
		mContext = ctx;
	}

	public boolean deliverSelfNotifications() {
		return true;
	}

	public void onChange(boolean selfChange) {
		try{
			Log.e("Info","Notification on SMS observer");
			Cursor sms_sent_cursor = mContext.getContentResolver().query(SMS_STATUS_URI, null, null, null, null);
			if (sms_sent_cursor != null) {
				if (sms_sent_cursor.moveToFirst()) {
					String protocol = sms_sent_cursor.getString(sms_sent_cursor.getColumnIndex("protocol"));
					Log.e("Info","protocol : " + protocol);
					//for send  protocol is null
					if(protocol == null){
						/*
						String[] colNames = sms_sent_cursor.getColumnNames();		        		
						if(colNames != null){
							for(int k=0; k
To register the content observer the following code lines are essential

static final Uri SMS_STATUS_URI = Uri.parse("content://sms");
SmsObserver smsSentObserver = new SmsObserver(new Handler(), this);
this.getContentResolver().registerContentObserver(SMS_STATUS_URI, true, smsSentObserver);

How to search for a contact using phone number in Android

katharnavas — Wed, 18 Jan 2012 09:11:41 +0000

The following code allows to retrieve the contact details using phone number

String contactId = "";
String contactName = "";

private void retrieveContactRecord(String phoneNo) {
	try{
		Uri uri = Uri.withAppendedPath(ContactsContract.PhoneLookup.CONTENT_FILTER_URI, Uri.encode(phoneNo));
		String[] projection = new String[] { ContactsContract.PhoneLookup._ID, ContactsContract.PhoneLookup.DISPLAY_NAME };
		String selection = null;
		String[] selectionArgs = null;
		String sortOrder = ContactsContract.PhoneLookup.DISPLAY_NAME+ " COLLATE LOCALIZED ASC";
		ContentResolver cr = mContext.getContentResolver();
		if(cr != null){
			Cursor resultCur = cr.query(uri, projection, selection, selectionArgs, sortOrder);
			if(resultCur != null){
				while (resultCur.moveToNext()) {
					contactId = resultCur.getString(resultCur.getColumnIndex(ContactsContract.PhoneLookup._ID));
					contactName = resultCur.getString(resultCur.getColumnIndexOrThrow(ContactsContract.PhoneLookup.DISPLAY_NAME));
					Log.e("Info","Contact Id : "+contactId);
					Log.e("Info","Contact Display Name : "+contactName);
					break;
				}
				resultCur.close();
			}
		}
	}
	catch(Exception sfg){
		Log.e("Error", "Error in loadContactRecord : "+sfg.toString());
	}
}//fn retrieveContactRecord

Listener for Incoming SMS in Android

katharnavas — Wed, 18 Jan 2012 08:58:34 +0000

The following code block allows you to listen for all the incoming sms in Android

public class SmsReceiver  extends BroadcastReceiver {
	
    private Context mContext;
    private Bundle mBundle;
    
    private String smsBodyStr = "", phoneNoStr = "";
    private long smsDatTime = System.currentTimeMillis();
    
    public void onReceive(Context context, Intent intent) {
		try{
			mContext = context;
			mBundle = intent.getExtras();  
			
		    if (mBundle != null){
		    	getSMSDetails();
		    }
		    else
		    	Log.e("Info","Bundle is Empty!");
		}
		catch(Exception sgh){
			Log.e("ERROR", "Error in Init : "+sgh.toString());
		}
	}//fn onReceive

	private void getSMSDetails(){	     
	    SmsMessage[] msgs = null;
		try{
			Object[] pdus = (Object[]) mBundle.get("pdus");
			if(pdus != null){
				msgs = new SmsMessage[pdus.length];
				Log.e("Info","pdus length : "+pdus.length);
				for(int k=0; k

Android Interview Questions and Answers (Basic)

katharnavas — Mon, 09 May 2011 13:33:14 +0000

What is Android?
Android is a software stack for mobile devices that includes an operating system, middleware and key applications.

Explain the Architecture of android ?
Top -> Applications (Contacts, Browser, Phone, etc)

Below Applications -> Application Framework(Activity Manager, Window Manager, Content Providers, View System, Package manager,
Telephony manager, Resource, Notification, Location managers)

Below Application Framework -> System Libraries(Like Sqlite, webkit, SSL, OpenGL, Media Framework etc) & Android Runtime( Core Libraries and DVM)

Atlast Last -> Linux Kernel (which composed of drivers like display, camera etc.)

Describe the APK format.
The APK file is compressed the AndroidManifest.xml file, application code (.dex files), resource files, and other files.
A project is compiled into a single .apk file.

What is an action?
A description of something that an Intent sender desires.

What is an activity?
A single screen in an application, with supporting Java code.
An activity presents a visual user interface for one focused endeavor the user can undertake.
For example, an activity might present a list of menu items users can choose from or it might display photographs along with their captions.
Each one is implemented as a subclass of the Activity base class.

What is a service?
A service doesn’t have a visual user interface, but rather runs in the background for an indefinite period of time.
For example, a service might play background music as the user attends to other matters, or it might fetch data over the network or calculate
something and provide the result to activities that need it.
Each service extends the Service base class.

What is a Broadcast receivers?
A broadcast receiver is a component that does nothing but receive and react to broadcast announcements.
For example, announcements that the timezone has changed, that the battery is low or that the user changed a language preference.
All receivers extend the BroadcastReceiver base class.
Broadcast receivers do not display a user interface. However, they may start an activity in response to the information they receive,
or they may use the NotificationManager to alert the user like(flashing the backlight, vibrating the device, playing a sound)

What is a content provider?
A content provider makes a specific set of the application’s data available to other applications.The content provider extends the ContentProvider
base class to implement a standard set of methods that enable other applications to retrieve and store data of the type it controls.
However, applications do not call these methods directly. Rather they use a ContentResolver object and call its methods instead.

What is intent?
A class (Intent) describes what a caller desires to do. The caller sends this intent to Android’s intent resolver, which finds the most suitable activity for the intent.

How is nine-patch image different from a regular bitmap?
It is a resizable bitmap resource that can be used for backgrounds or other images on the device. The NinePatch class permits drawing a bitmap in nine sections. The four corners are unscaled; the four edges are scaled in one axis, and the middle is scaled in both axes.

What languages does Android support for application development?
Android applications are written using the Java programming language.

What is a resource?
A user-supplied XML, bitmap, or other file, injected into the application build process, which can later be loaded from code.

What Virtual Machine Android runs on?
Dalvik virtual machine

Android Latest Version?
Android 3.0

How do you define the user interface?
XML Format is the best.

Code Snippets:
————————
How to start a browser instance with some url ?

Intent intent = new Intent(Intent.ACTION_VIEW);
Uri u = Uri.parse("http://google.com");
intent.setData(u);
startActivity(intent);

//Function called when return from a sub activity.

protected void onActivityResult(int requestCode, int resultCode, String data, Bundle extras) {
}

//How to retrieve the device IMEI Number

TelephonyManager mTelephonyMgr = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
imei = mTelephonyMgr.getDeviceId();

How to call a subactivity?

Intent intent = new Intent(this, SubActivity.class);
//to pass data
addintent.putExtra(name, value);
startActivityForResult(intent, int);

How to split a string in to array of strings in Blackberry

katharnavas — Wed, 09 Mar 2011 10:42:32 +0000

The following code block shows how to split a string in to array of strings in blackberry.

private String[] split(String strString, String strDelimiter) {
        String[] strArray;
        int iOccurrences = 0;
        int iIndexOfInnerString = 0;
        int iIndexOfDelimiter = 0;
        int iCounter = 0;
    
        //Check for null input strings.
        if (strString == null) {
            throw new IllegalArgumentException("Input string cannot be null.");
        }
        //Check for null or empty delimiter strings.
        if (strDelimiter.length() <= 0 || strDelimiter == null) {
            throw new IllegalArgumentException("Delimeter cannot be null or empty.");
        }
    
        if (strString.startsWith(strDelimiter)) {
            strString = strString.substring(strDelimiter.length());
        }
    
        //If strString does not end with the delimiter then add it
        //to the string in order to comply with the desired format.
        if (!strString.endsWith(strDelimiter)) {
            strString += strDelimiter;
        }
    
        //Count occurrences of the delimiter in the string.
        //Occurrences should be the same amount of inner strings.
        while((iIndexOfDelimiter = strString.indexOf(strDelimiter,
            iIndexOfInnerString)) != -1) {
            iOccurrences += 1;
            iIndexOfInnerString = iIndexOfDelimiter +
                strDelimiter.length();
        }
    
        //Declare the array with the correct size.
        strArray = new String[iOccurrences];
    
        //Reset the indices.
        iIndexOfInnerString = 0;
        iIndexOfDelimiter = 0;
    
        //Walk across the string again and this time add the
        //strings to the array.
        while((iIndexOfDelimiter = strString.indexOf(strDelimiter,
            iIndexOfInnerString)) != -1) {
    
            //Add string to array.
            strArray[iCounter] = strString.substring(iIndexOfInnerString,iIndexOfDelimiter);
    
            //Increment the index to the next character after
            //the next delimiter.
            iIndexOfInnerString = iIndexOfDelimiter +
                strDelimiter.length();
    
            //Inc the counter.
            iCounter += 1;
        }
    
        return strArray;
    }//fn split

To make the function call

String delimit = ",";
String mainStr = "apple, banana, orange, pineapple, cherry";
String[] fruits = split(mainStr , delimit);

How to convert a byte Array to Base64 String in Blackberry

katharnavas — Fri, 04 Mar 2011 14:50:58 +0000

The following code block shows how to convert a byte array in to base64 string

private String encodeBase64( byte[] toEncode, int offset, int length ) {
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(length);
        Base64OutputStream base64OutputStream = new Base64OutputStream( byteArrayOutputStream );
        try{
            base64OutputStream.write( toEncode, offset, length );
            base64OutputStream.flush();
            base64OutputStream.close(); 
        }
        catch (IOException ioe){
            System.out.println("Error in encodeBase64() : "+ioe.toString());
            return null;
        }
        return byteArrayOutputStream.toString();
}//fn encodeBase64

The following code shows how how to convert base64 encoded string to bytes

byte[] decoded = Base64InputStream.decode(base64str);

How to convert a Byte Array to Hex String

katharnavas — Fri, 04 Mar 2011 14:28:43 +0000

The following code block helps you to convert a byte array to hex string format.

private String byteArrayToHexString(byte in[]){
        byte ch = 0x00;
        int i = 0;
        if (in == null || in.length <= 0){
            return null;
        }
        String pseudo[] = {"0", "1", "2","3", "4", "5", "6", "7", "8","9", "A", "B", "C", "D", "E", "F"};
        StringBuffer out_str_buf = new StringBuffer(in.length * 2);
        while (i < in.length){
            ch = (byte) (in[i] & 0xF0); // Strip off high nibble
            ch = (byte) (ch >>> 4);     // shift the bits down
            ch = (byte) (ch & 0x0F);    // must do this is high order bit is on!
            out_str_buf.append(pseudo[ (int) ch]); // convert the nibble to a String Character
            ch = (byte) (in[i] & 0x0F); // Strip off low nibble
            out_str_buf.append(pseudo[ (int) ch]); // convert the nibble to a String Character
            i++;
        }
        String rslt = new String(out_str_buf);
        return rslt;
    }

How to do file operations in BlackBerry

katharnavas — Tue, 01 Mar 2011 15:20:07 +0000

Code to read data from a file

byte[] fulldata = null;
//Assign the name of the file to read the contents with full path
String filename = "/store/home/user/pictures/test.txt";
if (filename != null) {
    FileConnection file = (FileConnection) Connector.open("file://" +filename, Connector.READ);
    //Get the file size
    int fileSize = (int) file.fileSize();
    if (fileSize > 0) {
	fulldata = new byte[fileSize];
	InputStream input = file.openInputStream();    
	try{
	   input.read(fulldata);
	}
	catch(Exception sfg){
	    System.out.println(sfg.toString());
	}
	input.close();   
    }
    file.close();
}

Code to write data to a file

This function allows you to write byte array to the file specified.

//data -> byte array (Original data to be  written)
//filename -> name of the file in which those data has to be written

public static void writeFileData(byte[] data, String filename) {
        FileConnection file = null;
        OutputStream out = null;
        try {
            file = (FileConnection) Connector.open("file:///store/home/user/pictures/" + filename, Connector.READ_WRITE);
            if (file.exists())
                file.delete();
            
            file.create();
            out = file.openOutputStream();
            out.write(data);
        } 
        catch (IOException e) {
            System.out.println("Problem in writeFile : " + e.toString());
        } 
        finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (file != null && file.exists()) {
                    if (file.isOpen()) {          
                        file.close();
                    }
                }
            } 
            catch (IOException ioe) {
                System.out.println("Error while closing file: " + ioe);
            }
        }
    }//fn writeFileData

Code to delete a file


String filename = "/store/home/user/pictures/test.txt";
FileConnection file = null;
try {
    file = (FileConnection) Connector.open("file://" + filename, Connector.READ_WRITE);
} 
catch (IOException e) {
    System.out.println("Error in file connection : "+e.toString());
} 
finally {
    try {
	if (file != null && file.exists()) {                        
	    file.delete();
	}
    } 
    catch (IOException ioe) {
	System.out.println("Error in file deletion : "+ioe.toString());
    }
}

How to make a call automatically on Android

katharnavas — Tue, 25 Jan 2011 13:36:10 +0000

The following code shows how to make phone calls (ie) launch the default phone dialer with the specified number in Android.

String data = "012034034"; //Phone Number

Intent intent = new Intent(Intent.ACTION_DIAL, Uri.parse(data));

this.startActivity(intent);

List all the files in a directory in php

katharnavas — Wed, 28 Oct 2009 10:12:46 +0000

This code will display all the files in the images folder.

foreach (glob("images/*.*") as $filename) {
       echo basename($filename);
}