Counter restarts after killing app

Question

I have made an app that starts a counter when I hold the button, and stops counting as soon as I release the button, then start again as soon as I touch it again.. (The app is made to see how long time I can use, to touch a button.)

Anyway, I have made a way to save the data of the counter, so when I kill the app or press the "back button", the data of the counter saves. BUT as soon as I tap the button again it restarts! I can't find a way to fix this. I think it has to do something with:

chromo.setBase(SystemClock.elapsedRealtime()+time);

(Found under "ACTION_DOWN") I've used chronometer as my counter by the way. Please help me!

Here's my code:

public class MainActivity extends ActionBarActivity {

Button button1;
Chronometer chromo;
protected long time = 0;
private SharedPreferences prefs;




 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button1=(Button)findViewById(R.id.button1);
        chromo=(Chronometer)findViewById(R.id.chromo);
        prefs = getSharedPreferences("prefs", Context.MODE_PRIVATE);
        long savedValue = prefs.getLong("my_chrono", 0);

        if(savedValue == 0)
            chromo.setBase(SystemClock.elapsedRealtime());
        else
            chromo.setBase(SystemClock.elapsedRealtime() + savedValue);

        button1.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                // TODO Auto-generated method stub
                if(event.getAction() == MotionEvent.ACTION_DOWN){
                    chromo.setBase(SystemClock.elapsedRealtime()+time);
                    chromo.start();
                }
                else if( event.getAction() == MotionEvent.ACTION_UP){
                    time =chromo.getBase()-SystemClock.elapsedRealtime();
                    chromo.stop();
                    prefs.edit().putLong("my_chrono", time).apply();
                }
                return true;
            }
    });
}}