Android: UsageStats returning 0 on getTotalTimeInForeground() for certain apps

Question

I'm trying to fetch the daily screen time of each application that is installed on my phone using the following code from a service.

UsageStatsManager statsManager = (UsageStatsManager)service.getSystemService(Context.USAGE_STATS_SERVICE);

//todayDate is start of the day and today is current time

dailyUsage = statsManager.queryUsageStats(UsageStatsManager.INTERVAL_DAILY, todayDate.toDate().getTime(), today.toDateTime().getMillis());
for(UsageStats stats: dailyUsage){
  Long totalTime = stats.getTotalTimeInForeground();
  String app = stats.getPackageName();
  Log("TotalTimeUsedToday", app + " " + totalTime);
}

I'm getting duplicate apps and some apps show 0 totalTime though sometimes it shows correct screen time.

Answer 1

Since the queryUsageStats works in a weird way, I decided to drop it and use queryEvents instead. Here's the complete function that works like a charm for my use case:

private Map<String, Long> testUsageStats(long startTime) {

    long currTime = System.currentTimeMillis();
    UsageStatsManager mUsageStatsManager = (UsageStatsManager) getSystemService(Context.USAGE_STATS_SERVICE);
    UsageEvents usageEvents = mUsageStatsManager.queryEvents(startTime, currTime);

    Map<String, Long> eventUsage = new HashMap<>();
    Map<String, Long> totalUsage = new HashMap<>();

    String lastApp = "xx";

    while (usageEvents.hasNextEvent()) {
        UsageEvents.Event currentEvent = new UsageEvents.Event();
        usageEvents.getNextEvent(currentEvent);

        String app = currentEvent.getPackageName();
        Long time = currentEvent.getTimeStamp();

        if (currentEvent.getEventType() == UsageEvents.Event.ACTIVITY_RESUMED
            || currentEvent.getEventType() == UsageEvents.Event.ACTIVITY_PAUSED) {

            if (currentEvent.getEventType() == UsageEvents.Event.ACTIVITY_RESUMED) {
                eventUsage.put(app, time);
                lastApp = app;
            }
            else {
                if (eventUsage.containsKey(app))
                    if (totalUsage.containsKey(app))
                        totalUsage.put(app, totalUsage.get(app) + (time - eventUsage.get(app)));
                    else
                        totalUsage.put(app, (time - eventUsage.get(app)));
                eventUsage.remove(app);
            }
        }
    }

    if(eventUsage.containsKey(lastApp))
        if (totalUsage.containsKey(lastApp))
            totalUsage.put(lastApp, totalUsage.get(lastApp) + (System.currentTimeMillis() - eventUsage.get(lastApp)));
        else
            totalUsage.put(lastApp, (System.currentTimeMillis() - eventUsage.get(lastApp)));

    for (String key : totalUsage.keySet()) {
        Log("TestTimeUsed", key + " " + totalUsage.get(key));
    }

    return totalUsage;

}

This snippet covers the edge case of currently running app. Edge case at start time in which app has been started before the start time can also be handled with a bit of tweaking.