Android: How to override default behavior of dialer

Question

I am making modifications in a previous project, which is basically developed for kids and teenagers. It blocks text messaging, emails, calls and internet when a user drives at speed greater than 16 MPH. The service is activated through SMS. Modification is required as the app doesn't works on Android v4.1 and above. I have seen an app on PlayStore named Safely Go. This app has a button on click of which, status changes to driving. In this mode, if a user clicks on dialer, messaging, settings or browser, their own activity opens up, instead of default behavior. In short, in this mode a user cannot access anything except those applications, which the user has chosen to use during driving.

As per my requirement, the service will be activated through SMS. Once service gets activated, and user's speed reaches more than 16 MPH, I want that when user clicks on Dialer, my activity should open which will show a warning message, instead of opening dial pad. I am not getting how can I accomplish this feature. As a service has no direct interaction with user, so the android system cannot catch key event in service. Or, is there any other way to do this.

I simply want to know how can I override default behavior dialer. If someone has any information please share, as it would be of great help for me.

Answer 1

In the app that I mentioned in my question no default behavior was overridden. That was my mistake, I took it in wrong way. The same functionality can be achieved using Handler. In my app I used a service which starts on click of a button. Inside the service,, I had used handler. Below, I am posting the code snippet.

public class DialerService extends Service {
ActivityManager am;
List<RunningAppProcessInfo> mAppProcessInfosList;
private Runnable myRunnable;
boolean threadDone = true;
Handler mHandler;
boolean isLockedAppRunning = false;

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

public void onCreate() {
    am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
    mAppProcessInfosList = new ArrayList<ActivityManager.RunningAppProcessInfo>();
    mHandler = new Handler();
    Log.v("Dialer Service", "onCreate called");
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    myRunnable = new Runnable() {

        @Override
        public void run() {
            isRestrictedAppRunning();
        }
    };

    new Thread(new Runnable() {
        public void run() {
            while (threadDone) {

                try {
                    mHandler.post(myRunnable);
                } catch (Exception e) {

                }
            }
        }
    }).start();
    return START_STICKY;
}

private void isRestrictedAppRunning() {
    mAppProcessInfosList = am.getRunningAppProcesses();
    for (int i = 0; i < mAppProcessInfosList.size(); i++) {
        if (mAppProcessInfosList.get(i).processName
                .equals("com.android.phone")
                || mAppProcessInfosList.get(i).processName
                        .equals("com.android.email")
                || mAppProcessInfosList.get(i).processName
                        .equals("com.android.mms")) {
            isLockedAppRunning = true;
            Intent dialogIntent = new Intent(getBaseContext(),
                    TestActivity.class);
            dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            getApplication().startActivity(dialogIntent);
        }
    }
}

@Override
public void onDestroy() {
    super.onDestroy();
    this.threadDone = false;
}
}

This code is from my dummy app. There are lot more conditions in actual app and still lots of things need to implemented. But, what I needed actually will work in this way.