NetworkStatsManager.queryDetailsForUid not obtaining the "same" values as TrafficStats

Question

I'm comparing the new NetworkStats class with TrafficStats for measuring traffic for the network interfaces and a given application (pex Chrome)

Since TrafficStats has values since device boot the test that I'm performing is this:

1. Reboot phone.
2. Open Chrome.
3. Download 10 mb data (over WiFi).

The data obtained with TrafficStats is this:

TrafficStats.getTotalRxBytes() aprox 17.21 MB
TrafficStats.getUidRxBytes(chromeUid) aprox 13.22 MB

I grant the permission to NetworkStats and the values that I obtain are this:

wifiBucket.getRxBytes() + mobileBucket.getRxBytes() aprox 17.23 MB
dataFromWiFiBucket[1] + dataFromMobileBucket[1] gives 0 bytes

The code to obtain the data from NetworkStats is the following:

long timeStamp = System.currentTimeMillis();
long bootTime = System.currentTimeMillis() - SystemClock.elapsedRealtime();

NetworkStats.Bucket wifiBucket = networkStatsManager.querySummaryForDevice(ConnectivityManager.TYPE_WIFI, null, bootTime, timeStamp);
NetworkStats.Bucket mobileBucket = networkStatsManager.querySummaryForDevice(ConnectivityManager.TYPE_MOBILE, subscriberID, bootTime, timeStamp);

NetworkStats wifiBucketForApp = networkStatsManager.queryDetailsForUid(ConnectivityManager.TYPE_WIFI, null, bootTime, timeStamp, chromeUid);
NetworkStats mobileBucketForApp = networkStatsManager.queryDetailsForUid(ConnectivityManager.TYPE_MOBILE, subscriberID, bootTime, timeStamp, chromeUid);

long[] dataFromWiFiBucket = getDataFromBucket(wifiBucketForApp);
long[] dataFromMobileBucket = getDataFromBucket(mobileBucketForApp);

Where getDataFromBucket is:

@RequiresApi(api = Build.VERSION_CODES.M) public static long[] getDataFromBucket(NetworkStats bucketForApp) {

    long dataTx = 0;
    long dataRx = 0;

    NetworkStats.Bucket bucket;

    while (bucketForApp.hasNextBucket()) {
        bucket = new NetworkStats.Bucket();
        bucketForApp.getNextBucket(bucket);
        dataTx += bucket.getTxBytes();
        dataRx += bucket.getRxBytes();

    }

    return new long[]{dataTx, dataRx};
}

I've read somewhere that buckets are from two hours so I've added this code:

if (bootTime > (timeStamp - TimeUnit.HOURS.toMillis(TWO_HOURS))) {
    bootTime = timeStamp - TimeUnit.HOURS.toMillis(TWO_HOURS);
}

But data for chrome is still 0 because wifiBucketForApp and mobileBucketForApp do not have any buckets.

If I set bootTime to the beginning of the day (its 18:30 in my country) I obtain:

wifiBucket.getRxBytes() + mobileBucket.getRxBytes() aprox 44.74 MB (expected because is since the beginning of the day)
dataFromWiFiBucket[1] + dataFromMobileBucket[1] gives 26.32 MB

Does anybody know why I'm not obtaining the same values as TrafficStats since device boot from NetworkStatsManager for the Chrome app?

Answer 1

Since it's not your own app's traffic you need to allow manually Usage data access in the device settings.