Android 蓝牙 LE 屏蔽 UUID 过滤器

Question

我正在玩一个适用于 Android 和 iOS 的实验性Bluetooth LE 程序，现在我在 Android 端过滤 iOS 端发出的信标广告时遇到了一些问题。 Android 具有通过带有掩码的 UUID 过滤广告的功能（我需要这个，因为我试图让 UUID 以特定值开头）但我无法让它工作。这是我正在尝试的：

private void freshen() {
    // kill current scanner
    if (mLEScanner != null)
        mLEScanner.stopScan(mScanCallback);

    // set new one to be a match scanner
    ScanSettings settings = new ScanSettings.Builder()
            .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
            .build();

    List<ScanFilter> filters = new ArrayList<>();

    // create data uuid starting with the value 1
    ParcelUuid data = ParcelUuid.fromString("10000000-0000-0000-0000-000000000000");
    // create a mask to ensure only that value is searched
    ParcelUuid mask = ParcelUuid.fromString("10000000-0000-0000-0000-000000000000");

    // build the filter
    ScanFilter.Builder builder = new ScanFilter.Builder();
    builder.setServiceUuid(data, mask);
    ScanFilter filter = builder.build();

    // add the filter to the scanner
    filters.add(filter);
    mLEScanner.startScan(filters, settings, mScanCallback);
}

它产生的结果为零。即使我将所有掩码值设置为 0（这是忽略的数字），它仍然会产生零结果。当我删除过滤器时，会出现大量以 1 开头的结果。这在当前版本的 Android 中是否存在问题？

Answer 1

这不是解决此问题的方法，但我决定改为按 DeviceName 过滤，因为 Android 和 iOS 端都可以填充它。现在我专注于 iOS 到 Android 的通信 =>

iOS：

func centralManager(_: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi: NSNumber){

    delegate?.didDiscoverPeripheral(peripheral)
    let splitUp : [String] = "\(advertisementData)".components(separatedBy: "\n")
    if (splitUp.count > 1)
    {
        var chop = splitUp[1]
        let counter = chop.characters.count - 2
        chop = chop[0..<counter]
        let chopSplit : [String] = "\(chop)".components(separatedBy: "\"")

        if !(chopSplit.count > 1 && chopSplit[1] == "Device Information" && !sending)
        {
            let hexString = chop[4..<7] + chop[12..<19] + chop[21..<26]
            let hexArray = [hexString[0..<1], hexString[2..<3], hexString[4..<5], hexString[6..<7], hexString[8..<9], hexString[10..<11], hexString[12..<13], hexString[14..<15], hexString[16..<17]]
            let charArray = hexArray.map { Character(hexToScalar(char: $0)) }
            let string = String(charArray) as String
            if (string == "GoTcHa" + stringify(number: writing))
            {
                writing += 1
                let messageUUID = StringToUUID(hex: String(writing) + "hello" + String(writing))
                peripheralManager.stopAdvertising()
                let name = String(writing) as NSString
                peripheralManager.startAdvertising([CBAdvertisementDataServiceUUIDsKey: [CBUUID(string: messageUUID)], CBAdvertisementDataLocalNameKey: name])
            }
        }
    }
}

func StringToUUID(hex: String) -> String
{
    var rev = String(hex.characters.reversed())
    let hexData: NSData! = rev.data(using: String.Encoding.utf8, allowLossyConversion: false) as NSData!
    rev = hexData.toHexString()
    while(rev.characters.count < 31) {
        rev = "0" + rev;
    }
    rev = String(writing % 10) + rev[0..<30]
    let finalString = rev[0..<7] + "-" + rev[8..<11] + "-" + rev[12..<15] + "-" + rev[16..<19] + "-" + rev[20..<31]
    return finalString
}

更重要的是 Android 扫描方法，现在通过始终通过 DeviceName 查找下一条消息来忽略来自 iOS 的重复消息：

private void freshen() {
    if (mLEScanner != null)
        mLEScanner.stopScan(mScanCallback);
    ScanSettings settings = new ScanSettings.Builder()
            .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
            .setNumOfMatches(ScanSettings.MATCH_NUM_ONE_ADVERTISEMENT)
            .build();

    List<ScanFilter> filters = new ArrayList<>();

    ScanFilter filter = new ScanFilter.Builder()
            .setDeviceName("" + (reading % 10))
            .build();

    filters.add(filter);

    mLEScanner.startScan(filters, settings, mScanCallback);
}

我现在需要让 iOS 端更好地过滤 Android 的响应，但它在 Android 接收端有效。