TimeSpent event / screen

Hello,

I use Piwik in my Android app, and it’s work very good, but I have a question, I have 2 methods :

public static void sendEvent(Context context, Category eventCategory, String eventAction, String eventLabel, Long eventValue, String uid){
Tracker tracker = ((MyApplication)context.getApplicationContext()).getTracker();
TrackHelper.track().event(eventCategory.name(),eventAction).name(eventLabel).value(Float.parseFloat(eventValue.toString()));
}

public static void sendScreen(Context context, String screenName,String title){
Tracker tracker = ((MyApplication)context.getApplicationContext()).getTracker();
TrackHelper.track().screen(screenName).title(title).with(tracker);
}

For exemple, I am on a page, and a click on a button on this page, the time calculate by Piwik is (Screen : 1s ; Event 1 min) if a stay on the screen. But It’s not logic, how can the time only be calculated on the screen ? (Screen 1min ; Event ; 1s). Is this normal or is this my use that is not good?