Android BLE扫描无法发现Saveo C200 LF设备问题咨询

我正在开发的Android应用中实现了BLE设备发现与连接功能，该功能可正常发现部分BLE设备并完成配对、通信，但Saveo C200 LF设备始终无法出现在扫描结果中。我使用Google Play上的BLE Scanner应用扫描时，该设备可立即被发现并正常连接、获取服务。我的扫描逻辑未设置任何过滤规则，但无论如何操作都无法发现该设备，以下是相关代码实现：

private BLEScanCallback bleScanCallback = new BLEScanCallback();

public void bleStartBluetoothDiscovery() {
    BluetoothAdapter adapter = getBluetoothAdapter();
    if (adapter != null) {
        // for bluetooth le
        bleScanner = adapter.getBluetoothLeScanner();

        if (bleScanner != null) {
            // run the discovery for 12 seconds and then automatically stop
            bleScheduleEndDiscovery(12);

            List<ScanFilter> filters = null;
            
            ScanSettings scanSettings = new ScanSettings.Builder()
                .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
                .build()
            ;
            
            bleScanner.startScan(filters, scanSettings, this.bleScanCallback);

        }
    }
}


private static class BLEScanCallback extends ScanCallback {

    @Override
    public void onScanResult(int callbackType, ScanResult result) {
        BluetoothDevice device = result.getDevice();
        
        // the address of the Saveo C200 device, got it from the 
        // 3rd party BLE Scanner app that is able to see it when scanning.
        String crfidscanneraddress = "DD:0D:30:5E:1A:AC"; 
        
        String address = device.getAddress();
        String deviceName = device.getName();
        deviceName = (deviceName == null) ? "Unknown" : deviceName;

        if (address.equals(crfidscanneraddress)) {
            Log.d(TAG, "onScanResult: FOUND IT!!! ---&gt; " + deviceName + " [" + address + "] ");
            // I'm not just relying on this log, I'm checking through
            // all of the results and my device is not found even
            // with a different address. 
        }

        Log.d(TAG, "onScanResult: " + deviceName + " [" + address + "] ");

    }

    // ... etc

}

• 补全蓝牙权限配置：Android 12+需声明并动态请求BLUETOOTH_SCAN权限，若无需位置权限，需在权限中添加android:usesPermissionFlags="neverForLocation"；Android 11及以下需ACCESS_COARSE_LOCATION或ACCESS_FINE_LOCATION权限，权限缺失会导致部分BLE设备无法被扫描到。

• 优化扫描设置参数：当前扫描设置仅指定了低延迟模式，补充以下配置可提升设备捕获率：

  ScanSettings scanSettings = new ScanSettings.Builder()
      .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
      .setCallbackType(ScanSettings.CALLBACK_TYPE_ALL_MATCHES)
      .setMatchMode(ScanSettings.MATCH_MODE_AGGRESSIVE)
      .setNumOfMatches(ScanSettings.MATCH_NUM_MAX_ADVERTISEMENT)
      .build();
  

  这些参数会让扫描逻辑更积极，更容易捕获广播频率低、信号弱的BLE设备。

• 处理批量扫描结果：仅重写onScanResult会漏掉系统批量返回的扫描结果，需补充实现onBatchScanResults方法：

  @Override
  public void onBatchScanResults(List<ScanResult> results) {
      for (ScanResult result : results) {
          BluetoothDevice device = result.getDevice();
          String address = device.getAddress();
          String deviceName = device.getName() == null ? "Unknown" : device.getName();
          Log.d(TAG, "onBatchScanResults: " + deviceName + " [" + address + "] ");
          if (address.equals("DD:0D:30:5E:1A:AC")) {
              Log.d(TAG, "onBatchScanResults: FOUND IT!!! ---&gt; " + deviceName + " [" + address + "] ");
          }
      }
  }
  

• 支持扩展广播类型：Saveo C200 LF可能使用扩展广播，默认扫描设置不支持该类型，Android 8.0+可添加以下配置开启支持：

  ScanSettings scanSettings = new ScanSettings.Builder()
      .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
      .setLegacy(false) // 启用非传统扫描，适配扩展广播
      .build();
  

• 规避后台扫描限制：Android对后台BLE扫描有严格限制，测试时确保应用处于前台；若需后台扫描，Android 10+需额外申请ACCESS_BACKGROUND_LOCATION权限。

内容的提问来源于stack exchange，提问作者Kenny Wyland