蓝牙Beacon广播数据包格式以及解析

//Android Lollipop 版本以上的扫描回调函数
private ScanCallback mScanCallback = new ScanCallback() {
    @Override
    public void onScanResult(int callbackType, ScanResult result) {
        super.onScanResult(callbackType, result);
        final BluetoothDevice device = result.getDevice();
        final int rssi = result.getRssi();
        final byte[] scanRecord = result.getScanRecord().getBytes();
        // 判断Activity是否已经退出
        if (mainActivity == null) {
            return;
        }
        mainActivity.runOnUiThread(new Runnable() {
            @Override
            public void run() {
                String name = device.getName();
                if (name == null) {
                    //Log.d(TAG, "onLeScan: 此条数据被过滤---"+mac);
                    return;
                }
                Log.d(TAG, "onScanResult: 开始处理广播数据");
                handleScanResult(device, rssi, scanRecord);
            }
        });
    }

    @Override
    public void onBatchScanResults(List<ScanResult> results) {
        super.onBatchScanResults(results);
    }

    @Override
    public void onScanFailed(int errorCode) {
        super.onScanFailed(errorCode);
        Log.e(TAG, "启动扫描失败");
    }
};

// Android KITKAT 版本以下的扫描回调函数
private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback() {
    @Override
    public void onLeScan(final BluetoothDevice device, final int rssi, final byte[] scanRecord) {
        // 判断Activity是否已经退出
        if (mainActivity == null) {
            return;
        }
        mainActivity.runOnUiThread(new Runnable() {
            @Override
            public void run() {
                String name = device.getName();
                String mac = device.getAddress();
                // 官方提供的过滤UUID方法存在问题，此处自己先根据MAC过滤
                if (name == null || mac == null || !Arrays.asList(beaconMAC).contains(mac)) {
                    //Log.d(TAG, "onLeScan: 此条数据被过滤---"+mac);
                    return;
                }
                Log.d(TAG, "onLeScan: 开始处理广播数据");
                handleScanResult(device, rssi, scanRecord);
            }
        });
    }
};

// 处理广播数据
private void handleScanResult(BluetoothDevice device, int rssi, byte[] scanRecord) {
    int startIndex = 2;
    boolean patternFound = false;
    Log.d(TAG, "handleScanResult: "+bytesToHex(scanRecord));
    // 寻找是否存在beacon以及有效数据的起始索引
    while (startIndex <= 5) {
        if (((int) scanRecord[startIndex + 2] & 0xff) == 0x02
                && ((int) scanRecord[startIndex + 3] & 0xff) == 0x15) {
            patternFound = true;
            break;
        }
        startIndex++;
    }
    // 如果找到
    if (patternFound) {
        String ibeaconName = device.getName();
        String mac = device.getAddress();
        Log.d(TAG, "onLeScan: 搜索到一个Beacon设备" + mac);
        Log.d(TAG, "onLeScan: 它的名字是" + ibeaconName);
        String data = parseBLEData(scanRecord, startIndex);
        Log.d(TAG, "onLeScan: RSSI=" + rssi);
        String result = "Beacon设备名称：" + ibeaconName + "  MAC：" + mac + "\n";
        double distance = rssi2distance(rssi);
        String dis = String.format("%.2f", distance);
        result = result + data + "    RSSI：" + rssi + " ( " + dis + " )";
        Log.d(TAG, result);
    } else {
        String name = device.getName();
        if (name == null) {
            //Log.d(TAG, "onLeScan: 搜索到一个普通蓝牙设备，它的MAC是"+device.getAddress());
        } else {
            //Log.d(TAG, "onLeScan: 搜索到一个普通蓝牙设备，它的名字是"+name);
        }
    }
}

// 根据RSSI计算距离
public double rssi2distance(int rssi) {
    int iRssi = Math.abs(rssi);
    // 发射端和接收端相隔1米时的信号强度
    int A = 59;
    // 环境噪声衰减因子
    double n = 2.0;
    double power = (iRssi - A) / (10 * n);
    return Math.pow(10, power);
}

// 字节数据转为Hex: 1 byte = 8bit = 两个16进制数字
public String bytesToHex(byte[] src) {
    StringBuilder stringBuilder = new StringBuilder("");
    for (int i = 0; i < src.length; i++) {
        int v = src[i] & 0xFF;
        String hv = Integer.toHexString(v);
        if (hv.length() < 2) {
            stringBuilder.append(0);
        }
        stringBuilder.append(hv);
    }
    return stringBuilder.toString();
}

// 格式化UUID
public String parseUUID(String data) {
    String uuid = "";
    if (data.length() == 32) {
        uuid = data.substring(0, 8) + "-"
                + data.substring(8, 12) + "-"
                + data.substring(12, 16) + "-"
                + data.substring(16, 20) + "-"
                + data.substring(20);
    } else {
        showTips(getString(R.string.toast_uuid_not_found));
    }
    return uuid;
}

// 解析BLE数据
public String parseBLEData(byte[] scanRecord, int startIndex) {
    // uuid的长度是16bytes
    byte[] uuidBytes = new byte[16];
    System.arraycopy(scanRecord, startIndex + 4, uuidBytes, 0, 16);
    String hexString = bytesToHex(uuidBytes);
    // beacon的UUID值
    String uuid = parseUUID(hexString);
    // beacon的Major值
    int major = (scanRecord[startIndex + 20] & 0xff) * 0x100
            + (scanRecord[startIndex + 21] & 0xff);
    // ibeacon的Minor值
    int minor = (scanRecord[startIndex + 22] & 0xff) * 0x100
            + (scanRecord[startIndex + 23] & 0xff);

    int txPower = (scanRecord[startIndex + 24]);
    Log.d(TAG, "onLeScan: 它的UUID是" + uuid + "，txPower是" + txPower);
    Log.d(TAG, "onLeScan: major=" + major + "，minor=" + minor);
    return "UUID：" + uuid + "\nmajor：" + major + "    minor：" + minor + "\ntxPower：" + txPower;
}