Block outgoing SMS by contentObserver

I want to block SMS by contentObserver. For that I want to get the phone number of the SMS first. What do I do to get the number? This is the code that I have, just counting the number of SMS.

package com.SMSObserver4;
import android.app.Activity;
import android.database.ContentObserver;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.provider.Contacts;
import android.provider.Contacts.People.Phones;

public class SMSObserver4 extends Activity {
        /** Called when the activity is first created. */
     private static final String Address = null;
    @Override
        public void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.main);
                setReceiver();
        }

        private SmsSentCounter smsSentObserver = new SmsSentCounter(new Handler()开发者_JAVA百科);
        private int sms_sent_counter = 0;

        private void setReceiver() {
                this.getContentResolver().registerContentObserver(
                                Uri.parse("content://sms"), true, smsSentObserver);
        }
        class SmsSentCounter extends ContentObserver {

                public SmsSentCounter(Handler handler) {
                        super(handler);
                        // TODO Auto-generated constructor stub
                }
                @Override
                public void onChange(boolean selfChange) {
                        // TODO Auto-generated method stub

                    try{
                    System.out.println ("Calling onChange new");
                        super.onChange(selfChange);
                        Cursor sms_sent_cursor = SMSObserver4.this.managedQuery(Uri
                                        .parse("content://sms"), null, "type=?",
                                        new String[] { "2" }, null);
                        if (sms_sent_cursor != null) {
                                if (sms_sent_cursor.moveToFirst()) {
                                        sms_sent_counter++;
                                        System.out.println("test" + sms_sent_counter);
                                }
                        }
                        Uri phoneUri = Uri.withAppendedPath(Contacts.Phones.CONTENT_FILTER_URL, Address);
                        if (phoneUri != null) {
                          Cursor phoneCursor = getContentResolver().query(phoneUri, new String[] {Phones._ID, Contacts.Phones.PERSON_ID}, null, null, null);
                          if (phoneCursor.moveToFirst()) {
                            long person = phoneCursor.getLong(1); // this is the person ID you need
                          }
                        }
                }catch(Exception e)
                {}
                    }
        }
}

I have done a lot of tests and I found this to be impossible. That's because when the messaging application inserts a new record in the SMS content provider, it is already trying to send the SMS. So, even if you detect the SMS in the content://sms/outbox URI, it will be too late to stop it. In fact, there's no way to stop it... it all depends on the SMS application, which you can't interrupt.

Nope, you cant. Observer will comeinto affect after dataset has been modified, by that time sms will already be on the way for delivery. Infact by any means you cant block outgoing sms.