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As filter in startLeScan is not working, use this function to filter the UUID
// Solution from https://stackoverflow.com/questions/18019161/startlescan-with-128-bit-uuids-doesnt-work-on-native-android-ble-implementation
List<string> ParseUUIDs(byte[] advertisedData)
{
List<string> uuids = new List<string>();
int offset = 0;
while (offset < (advertisedData.Length - 2))
{
int len = advertisedData[offset++];
if (len == 0)
break;
int type = advertisedData[offset++];
switch (type)
{
case 0x02: // Partial list of 16-bit UUIDs
case 0x03: // Complete list of 16-bit UUIDs
while (len > 1)
{
int uuid16 = advertisedData[offset++];
uuid16 += (advertisedData[offset++] << 8);
len -= 2;
uuids.Add($"0000{uuid16.ToString("X")}-0000-1000-8000-00805f9b34fb");
}
break;
case 0x06:// Partial list of 128-bit UUIDs
case 0x07:// Complete list of 128-bit UUIDs
// Loop through the advertised 128-bit UUID's.
while (len >= 16)
{
try
{
// Wrap the advertised bits and order them.
Java.Nio.ByteBuffer buffer = Java.Nio.ByteBuffer.Wrap(advertisedData,
offset++, 16).Order(Java.Nio.ByteOrder.LittleEndian);
long mostSignificantBit = buffer.Long;
long leastSignificantBit = buffer.Long;
uuids.Add(new UUID(leastSignificantBit,
mostSignificantBit).ToString());
}
catch (Java.Lang.IndexOutOfBoundsException e)
{
continue;
}
finally
{
// Move the offset to read the next uuid.
offset += 15;
len -= 16;
}
}
break;
default:
offset += (len - 1);
break;
}
}
return uuids;
}
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