Grand total of steps taken by user - Android Application Stepometer

I have an application which has an in game stepometer so calculates the user's steps in the background as they play the game. It works fine, my issue is the following

• Have a grand total of steps taken by the user since starting to play the game

For example, in one session he had 200 steps and in the next 300. I would like to save this total of 500 steps so that I can then display achievements to the user such as. Congrats you walked 1000 steps since beginning the game.

This is my stepometer code which I found online and currently using in my application.

import android.app.Activity;
import android.content.Context;
import android.hardware.*;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;

public class StepCounterActivity extends Activity implements SensorEventListener {

    private SensorManager sensorManager;
    private TextView count;
    boolean activityRunning;
    int totalSteps;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_step_counter);
        count = (TextView) findViewById(R.id.count);

        sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
    }

    @Override
    protected void onResume() {
        super.onResume();
        activityRunning = true;
        Sensor countSensor = sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
        if (countSensor != null) {
            sensorManager.registerListener(this, countSensor, SensorManager.SENSOR_DELAY_UI);
        } else {
            Toast.makeText(this, "Count sensor not available!", Toast.LENGTH_LONG).show();
        }    
    }

    @Override
    protected void onPause() {
        super.onPause();
        activityRunning = false;
        // if you unregister the last listener, the hardware will stop detecting step events
//        sensorManager.unregisterListener(this);
    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        if (activityRunning) {
            count.setText(String.valueOf(event.values[0]));
            //maybe add to a variable the number of steps somehow?
        }    
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
    }
}

Since you are not using Service below will work fine for you. Maintain A global variable totalSteps to count the total no of steps taken by user over all sessions.

private int totalSteps = 0;
@Override
public void onSensorChanged(SensorEvent event) {

    totalSteps += (int)event.values[0];

    if (activityRunning) {
        count.setText(String.valueOf(totalSteps));
    }

}

Keep in mind totalSteps would be lost once app is kill or closed. To overcome this situation you should try using SharedPreferences.