Blocking outgoing calls and texts (BroadcastReceiver or Service?) [duplicate]

This question already has an answer here: Closed 11 years ago.

Possible Duplicate:

How to block outgoing calls and texts to contacts (Prevent drunk dialing)

For one of my computer science classes, I am making an app to prevent people from drunk dialing. Basically the user clicks a button before they start drinking which turns off all outgoing call/text functionality until they pass a sobriety test (answer a math question). I'm stuck at how to block calls/texts from when they press the "Start" button until they answer the question correctly. So far it seems that most people recommend using a BroadcastReceiver to block calls, but I don't think this will work in my case because you can't start and stop a broadcast receiver when a button the "Start" button is pushed or the correct text is inputted. Am I missing something? Would it be possible to use a background service to accomplish this instead or is there a good way to use a BroadcastReceiver in this manner?

Here is my code:

public class MainActivity extends Activity {

    int answer;

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

        final EditText userInput = (EditText) findViewById(R.id.answerinput);
        userInput.setEnabled(false);

        //This creates the button object for the "Start Drinking" button
        final Button leftbutton = (Button) findViewById(R.id.leftbutton);

        //This creates the button object for the "Make Call" button
        final Button rightbutton = (Button) findViewById(R.id.rightbutton);
        rightbutton.setEnabled(false);

        leftbutton.setOnClickListener(new View.OnClickListener() {
            /**
             * Description: This method listens for a click on the "Make Call" button. Once
             * the button is clicked, this method will call other methods in order to create a 
             * random math problem, display this problem to the user, and check to see if the user
             * answered correctly. If they did, then this method will call the dialer to make
             * a phone call.
             * @author Matt
             * @params A view object to see the button
             * @return void
             * @throws None
             */
            public void onClick(View v) {
                rightbutton.setEnabled(true);
                leftbutton.setEnabled(false);
            }
        });


        rightbutton.setOnClickListener(new View.OnClickListener() {
            /**
             * Description: This method listens for a click on the "Send Text" button. Once
             * the button is clicked, this method will call other methods in order to create a 
             * random math problem, display this problem to the user, and check to see if the user
             * answered correctly. If they did, then this method will call the text messaging service
             * to allow the user to send a text. 
             * @author Matt
             * @params A view object to see the button
             * @return void
             * @throws None
 开发者_StackOverflow社区            */
            public void onClick(View v) {
                answer = createMathProblem();
                userInput.setEnabled(true);
            }
        });

        userInput.setOnKeyListener(new OnKeyListener() {

            public boolean onKey(View v, int keyCode, KeyEvent event) {
                String text = userInput.getText().toString();
                // If the event is a key-down event on the "enter" button
                if ((event.getAction() == KeyEvent.ACTION_DOWN)
                        && (keyCode == KeyEvent.KEYCODE_ENTER)) {
                    if (matchAnswer(answer, Integer.parseInt(text))) {
                        leftbutton.setEnabled(true);
                        rightbutton.setEnabled(false);
                        userInput.setEnabled(false);
                        //airplane();
                        Toast.makeText(MainActivity.this, "Correct!", Toast.LENGTH_LONG).show();
                    }
                    return true;
                }
                return false;
            }
        });

    }

    /**
     * Description: This method checks to see if the user answered the math problem
     * correctly.
     * @author Matt
     * @params The correct answer to the math problem and the user's input answer
     * @return True or false depending on if the user answered correctly
     * @throws None
     */
    public boolean matchAnswer(int correctAnswer, int userAnswer) {
        return (correctAnswer == userAnswer);
    }

    /**
     * Description: This method creates a random math problem for the user to 
     * answer and displays it to the screen. 
     * @author Matt
     * @params None
     * @return The correct answer to the math problem.
     * @throws None
     */
    public int createMathProblem() {
        int random1 = (int) (Math.random() * 100);
        int random2 = (int) (Math.random() * 100);
        int answer = random1 + random2;
        Toast.makeText(MainActivity.this, random1 + " + " + random2 + " = ?", Toast.LENGTH_LONG).show();
        return answer;
    }


}

---

You can take help from the following links:

For detecting outgoing calls:

http://www.krvarma.com/2010/08/detecting-incoming-and-outgoing-calls-in-android/

and for blocking outgoing calls:

http://code.google.com/p/unlocking-android/source/browse/chapter7/trunk/src/com/msi/manning/telephonyexplorer/OutgoingCallReceiver.java?spec=svn78&r=78