Q:

How to check for update of an event in android?

My application has the following modules,

To collect users CB location code.
To save that in a database of user's choice, say for example my CB code is 465783 and I can save that as 'College' in my database.
To provide alarm feature, in this module I can give a text input say I give it as 'College' and when the Cell Broadcast is updated if the value college matches alarm is given out.

Now, in my below code I've achieved first 2 modules and also the required database entries, databases search etc, I'm not able to read the updated CB location value.
public class Alarm extends MainActivity {

public String str;

public void onReceive(Context context, Intent intent) {
    //---get the CB message passed in---
    Bundle bundle = intent.getExtras();        
    SmsCbMessage[] msgs = null;
    str = "";            
    if (bundle != null)  {
        //---retrieve the SMS message received---
        Object[] pdus = (Object[]) bundle.get("pdus");
        msgs = new SmsCbMessage[pdus.length];            
        for (int i=0; i<msgs.length; i++) {
            msgs[i] = SmsCbMessage.createFromPdu((byte[])pdus[i]);                
            str += "CB " + msgs[i].getGeographicalScope() + msgs[i].getMessageCode() + msgs[i].getMessageIdentifier() + msgs[i].getUpdateNumber();                     
            str += " :";
            str += "\n";        
        }
        }
        }

EditText user_value;
Button startalarm;
Button stopalarm;

/** Called when the activity is first created. */
@Override
 public void onCreate(Bundle savedInstanceState) 
{
 super.onCreate(savedInstanceState);
 setContentView(R.layout.third);

 startalarm = (Button) findViewById(R.id.startalarm);
 stopalarm = (Button) findViewById(R.id.stopalarm);
user_value = (EditText) findViewById(R.id.user_value);

final Ringtone ringtone;
ringtone = RingtoneManager.getRingtone(getBaseContext(),     RingtoneManager.getDefaultUri(RingtoneManager.TYPE_RINGTONE));

startalarm.setOnClickListener(new View.OnClickListener() 
{

public void onClick(View arg0)
{
        // TODO Auto-generated method stub
if(user_value.length()==0)
{
    Toast.makeText(getBaseContext(), "Please enter a value.", Toast.LENGTH_LONG).show();
}

    Toast.makeText(getApplicationContext(), "alarm set", Toast.LENGTH_LONG).show();

//I want my alarm event to be started from here whenever a new CB sms arrives.

SQLiteDatabase aa = openOrCreateDatabase("MLIdata", MODE_WORLD_READABLE, null);
    Cursor c = aa.rawQuery("SELECT CblocationName FROM MLITable WHERE CblocationCode = '"+str+"'", null);
    c.moveToFirst();
    c.getString(c.getColumnIndex("CblocationName"));
    String sas = user_value.getText().toString();
    if(sas.equals(c.getString(c.getColumnIndex("CblocationName"))))
    {
        //here comes the alarm code

        if(ringtone == null)
        {
            Log.d("Debug", "ringtone is null");
        }
        else
        {
            ringtone.play();

        }
    }
}

});

stopalarm.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {
    // TODO Auto-generated method stub
    ringtone.stop();
}
});
}
}

Detailed Explanation : whenever a user enters a new tower location he gets the updated Cell Broadcast message from the tower, so when this cbsms arrives I need to start my event of retrieving the CB area code and compare it with my database of area codes (which obviously have corresponding area code names set by the user) and when there is a match between the user given area name's corresponding area code with my current area code an alarm needs to be started, here I'm not able to do detect the arrival of updated location. 
If further explanation is required of my problem statement, please comment.
From the comments received below, I've deduced that I'd need a receiver class, I've created one for my widget which does the same function (Displays the Cb location code on the widget), Now I do not how to activate that in my app.
My WidgetReceiver.java
public class CbReceiver extends BroadcastReceiver
    {

        public void onReceive(Context context, Intent intent) {
            //---get the CB message passed in---
            Bundle bundle = intent.getExtras();        
            SmsCbMessage[] msgs = null;
            String str = "";            
            if (bundle != null)  {
                //---retrieve the SMS message received---
                Object[] pdus = (Object[]) bundle.get("pdus");
                msgs = new SmsCbMessage[pdus.length];            
                for (int i=0; i<msgs.length; i++) {
                    msgs[i] = SmsCbMessage.createFromPdu((byte[])pdus[i]);                
                    str += "CB " + msgs[i].getGeographicalScope() + msgs[i].getMessageCode() + msgs[i].getMessageIdentifier() + msgs[i].getUpdateNumber();                     
                    str += " :";
                    str += msgs[i].getMessageBody().toString();
                    str += "\n";       

                abortBroadcast();
                Toast.makeText(context, str, Toast.LENGTH_LONG).show();

                    AppWidgetManager appWidgetManager =     AppWidgetManager.getInstance(context);
            RemoteViews remoteViews = new RemoteViews(context.getPackageName(),R.layout.widget);
            ComponentName thisWidget = new ComponentName(context,MyWidget.class);
            remoteViews.setTextViewText(R.id.update,str);
            appWidgetManager.updateAppWidget(thisWidget, remoteViews);

        }                         
    }}
}

Help required.
Thank you.

A:

Start your activity from your receiver on tower change. Use Intents to start your activity from receivers.
Ex: Refer this alarm example for above point, Alarm Example
Register your receiver in Android Manifest.xml. 
Send a broadcast message from your receiver class also update your DB inside your receiver.
Catch the same in your activity. You can use Custom Broadcast for this. 
Now activate your alarm in activity.

Hope these steps will help you. Refer the example I have mentioned.

