Question

我正在编写一个BLE扫描器，它经常扫描外围设备，连接和断开连接。

我正在“循环”扫描-将其关闭2秒钟，然后再打开10秒钟-因为我在某处（会尝试查找参考）读到（否则将查找参考），否则该操作系统（在Android 7.0之后）将停止扫描在大约30分钟后在后台显示。我也经历了这样的事情。

问题是，在某些设备上（例如，摩托罗拉Moto Z和Google Pixel），出现错误SCAN_FAILED_ALREADY_STARTED，表明该应用程序已经开始使用这些参数进行扫描。

但是，使用我的扫描算法，我强制要求stopScan在尝试startScan之前必须进行调用。这是一个相关的代码示例，该代码示例在提到的设备上产生了错误。这只是代码的扫描部分。

private final int SCANNER_DOWN_TIME = 2000;
private final int SCANNER_LIFETIME_MS = 10000;

private Runnable runnable = new Runnable() {
        private BluetoothLeScanner scanner;

        final ScanSettings.Builder builder = new ScanSettings.Builder();
        final ScanSettings settings = builder.setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
                .build();

        public void run() {
            try {
                bootScanner();
            } catch (Exception e) {
                Sentry.capture(e);
            }
        }

        class StartScannerAndScheduleReboot implements Runnable {
            @Override
            public void run() {
                if (bluetoothAdapter.isEnabled()) {
                    scanner = bluetoothAdapter.getBluetoothLeScanner();
                    if (scanner != null) {
                        scanner.startScan(null, settings, sensorReadingHandler);
                    }
                } else {
                    bluetoothAdapter.enable();
                }

                bootScanHandler = new Handler(Looper.getMainLooper());
                bootScan = new RebootScanner();
                bootScanHandler.postDelayed(bootScan, SCANNER_LIFETIME_MS);
            }
        }

        class RebootScanner implements Runnable {
            @Override
            public void run() {
                bootScanner();
            }
        }

        private void bootScanner() {
            try {
                scanner.stopScan(sensorReadingHandler);
            } catch (Exception e) {
                /* We can ignore this - there are cases that this will happen & it's ok */
            }

            startScanHandler = new Handler(Looper.getMainLooper());
            startScan = new StartScannerAndScheduleReboot();
            startScanHandler.postDelayed(startScan, SCANNER_DOWN_TIME);
        }

        private ScanCallback sensorReadingHandler = new ScanCallback() 

{ /* I don't believe the scanCallback code is relevant, as this happens before any connections are even attempted. */ }

        };

毫不奇怪，该应用程序仍然能够读取BLE传输，但其中一些被丢弃。这使我相信我不应该只忽略此错误。

BLE SCAN_FAILED_ALREADY_STARTED（错误代码1）仅在某些设备上

0 个答案: