我正在尝试使用 RxAndroidBLE 扫描设备，但扫描立即停止且没有扫描结果。这是我的代码：
Disposable flowDisposable = rxBleClient.observeStateChanges()
.startWith(rxBleClient.getState())
.switchMap(state -> { // switchMap makes sure that if the state will change the rxBleClient.scanBleDevices() will dispose and thus end the scan
switch (state) {
case READY:
// everything should work
Log.d("rxble","READY scan start:" );
return rxBleClient.scanBleDevices(
new ScanSettings.Builder()
.setScanMode(ScanSettings.SCAN_MODE_BALANCED) // change if needed
.setCallbackType(ScanSettings.CALLBACK_TYPE_ALL_MATCHES) // change if needed
.build(),
new ScanFilter.Builder()
.setDeviceName("localname")
.build()
);
case BLUETOOTH_NOT_AVAILABLE:
Log.d("rxble","no Bluetooth" );
// basically no functionality will work here
case LOCATION_PERMISSION_NOT_GRANTED:
// scanning and connecting will not work
Log.d("rxble","no locate permission" );
case BLUETOOTH_NOT_ENABLED:
// scanning and connecting will not work
Log.d("rxble","Bluetooth not enabled" );
case LOCATION_SERVICES_NOT_ENABLED:
// scanning will not work
Log.d("rxble","location services not enabled" );
default:
return Observable.empty();
}
})
.timeout(10, TimeUnit.SECONDS)
.subscribe(
rxBleScanResult -> {
String sc = rxBleScanResult.toString();
Log.d("rxble","scan result:" + sc); // Process scan result here.
},
throwable -> {
// Handle an error here.
Log.d("rxble","scan error" + throwable.getMessage());
}
);
// When done, just dispose.
flowDisposable.dispose();
我的外围设备是一个 Arduino 板，它可以使用标准的 BLE 扫描仪（如“LikeBlue”）进行扫描 这是我的日志：
2021-06-21 19:29:11.272 3853-3853/heikki.fi.bttest D/rxble: READY scan start:
2021-06-21 19:29:11.411 3853-3853/heikki.fi.bttest D/RxBle#ClientOperationQueue: QUEUED ScanOperationApi21(144257920)
2021-06-21 19:29:11.455 3853-10348/heikki.fi.bttest D/RxBle#ClientOperationQueue: STARTED ScanOperationApi21(144257920)
2021-06-21 19:29:11.483 3853-10348/heikki.fi.bttest I/RxBle#ClientOperationQueue: RUNNING ScanOperationApi21{ANY_MUST_MATCH -> nativeFilters=[BluetoothLeScanFilter [mDeviceName=localname, MAC=null, mUuid=null, mUuidMask=null, mSolicitedUuid=null, mSolicitedUuidMask=null, mServiceDataUuid=null, mServiceData=null, mServiceDataMask=null, mManufacturerId=-1, mManufacturerData=null, mManufacturerDataMask=null]]}
2021-06-21 19:29:11.506 3853-11095/heikki.fi.bttest I/RxBle#QueueOperation: Scan operation is requested to start.
2021-06-21 19:29:11.513 3853-11095/heikki.fi.bttest D/RxBle#ScanOperationApi21: No library side filtering —> debug logs of scanned devices disabled
2021-06-21 19:29:11.668 3853-10348/heikki.fi.bttest D/RxBle#ClientOperationQueue: FINISHED ScanOperationApi21(144257920) in 227 ms
2021-06-21 19:29:12.018 3853-11095/heikki.fi.bttest I/RxBle#CancellableDisposable: Scan operation is requested to stop.
所以这里有什么问题？ 我试过有或没有超时，有或没有扫描过滤器，但没有任何效果。 我的 Arduino 有固定的 macaddress，所以我还是尝试连接和读取特性：
String macAddress = "84:CC:A8:2E:24:6A";
RxBleDevice device = rxBleClient.getBleDevice(macAddress);
Log.d("rxble","trying to read characteristic" );
Disposable disposable =device.establishConnection(false)
.flatMapSingle(rxBleConnection -> rxBleConnection.readCharacteristic(UUID.fromString(PIN_UUID)))
// .observeOn(AndroidSchedulers.mainThread())
.subscribe(
characteristicValue -> {
// Read characteristic value.
Log.d("rxble","read value:" + new String(characteristicValue));
// rtext.setText(new String(characteristicValue));
},
throwable -> {
Log.d("rxble","read error" + throwable.getMessage());
// Handle an error here.
}
);
disposable.dispose();
这不会出错，但不会读取已知特征，这里是 logcat：
2021-06-21 19:52:25.542 3853-3853/heikki.fi.bttest D/rxble: trying to read characteristic
2021-06-21 19:52:25.646 3853-24305/heikki.fi.bttest D/RxBle#ClientOperationQueue: QUEUED ConnectOperation(156775354)
2021-06-21 19:52:25.683 3853-10348/heikki.fi.bttest D/RxBle#ClientOperationQueue: STARTED ConnectOperation(156775354)
2021-06-21 19:52:25.705 3853-10348/heikki.fi.bttest I/RxBle#ClientOperationQueue: RUNNING ConnectOperation{MAC='XX:XX:XX:XX:XX:XX', autoConnect=true}
2021-06-21 19:52:25.815 3853-11095/heikki.fi.bttest V/RxBle#BleConnectionCompat: Connecting without reflection
2021-06-21 19:52:25.878 3853-10348/heikki.fi.bttest D/RxBle#ClientOperationQueue: FINISHED ConnectOperation(156775354) in 195 ms
2021-06-21 19:52:26.888 3853-24305/heikki.fi.bttest D/RxBle#ConnectionOperationQueue: Connection operations queue to be terminated (MAC='XX:XX:XX:XX:XX:XX')
com.polidea.rxandroidble2.exceptions.BleDisconnectedException: Disconnected from MAC='XX:XX:XX:XX:XX:XX' with status -1 (UNKNOWN)
at com.polidea.rxandroidble2.internal.serialization.ConnectionOperationQueueImpl.onConnectionUnsubscribed(ConnectionOperationQueueImpl.java:162)
at com.polidea.rxandroidble2.internal.connection.ConnectorImpl$1$1.run(ConnectorImpl.java:65)
at io.reactivex.internal.operators.observable.ObservableDoFinally$DoFinallyObserver.runFinally(ObservableDoFinally.java:142)
at io.reactivex.internal.operators.observable.ObservableDoFinally$DoFinallyObserver.dispose(ObservableDoFinally.java:98)
at io.reactivex.internal.disposables.DisposableHelper.dispose(DisposableHelper.java:124)
at io.reactivex.internal.operators.observable.ObservableSubscribeOn$SubscribeOnObserver.dispose(ObservableSubscribeOn.java:73)
at io.reactivex.internal.operators.observable.ObservableUnsubscribeOn$UnsubscribeObserver$DisposeTask.run(ObservableUnsubscribeOn.java:95)
at io.reactivex.internal.schedulers.ScheduledDirectTask.call(ScheduledDirectTask.java:38)
at io.reactivex.internal.schedulers.ScheduledDirectTask.call(ScheduledDirectTask.java:26)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:301)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.lang.Thread.run(Thread.java:923)
2021-06-21 19:52:26.914 3853-24305/heikki.fi.bttest D/RxBle#ClientOperationQueue: QUEUED DisconnectOperation(170873441)
2021-06-21 19:52:26.927 3853-24304/heikki.fi.bttest V/RxBle#Executors: Terminated (MAC='XX:XX:XX:XX:XX:XX')
2021-06-21 19:52:26.950 3853-10348/heikki.fi.bttest D/RxBle#ClientOperationQueue: STARTED DisconnectOperation(170873441)
2021-06-21 19:52:26.973 3853-10348/heikki.fi.bttest I/RxBle#ClientOperationQueue: RUNNING DisconnectOperation{MAC='XX:XX:XX:XX:XX:XX'}
2021-06-21 19:52:27.061 3853-10348/heikki.fi.bttest D/RxBle#ClientOperationQueue: FINISHED DisconnectOperation(170873441) in 128 ms
答案 0 :(得分：0)
您面临的问题是立即处理订阅。您应该在完成扫描/连接后调用 disposable.dispose() （因此 // When done, just dispose. – 很可能是在您获得结果后或不再感兴趣时。
答案 1 :(得分：0)
感谢您的帮助。我现在可以进行扫描了，但是文档和示例（RxAndroidBLE）至少对于像我这样的 RXJava 新手来说确实具有误导性！ 这是扫描的工作代码：
enter code here
if (flowDisposable!=null) // dispose first if not disposed
if (!flowDisposable.isDisposed())
flowDisposable.dispose();
flowDisposable = rxBleClient.observeStateChanges()
.startWith(rxBleClient.getState())
.switchMap(state -> { // switchMap makes sure that if the state will change the rxBleClient.scanBleDevices() will dispose and thus end the scan
switch (state) {
case READY:
// everything should work
Log.d("rxble","READY scan start:" );
return rxBleClient.scanBleDevices(
new ScanSettings.Builder()
.setScanMode(ScanSettings.SCAN_MODE_BALANCED) // change if needed
.setCallbackType(ScanSettings.CALLBACK_TYPE_FIRST_MATCH) // change if needed
.build(),
new ScanFilter.Builder()
.setDeviceName("localname")
.build()
);
case BLUETOOTH_NOT_AVAILABLE:
Log.d("rxble","no Bluetooth" );
// basically no functionality will work here
case LOCATION_PERMISSION_NOT_GRANTED:
// scanning and connecting will not work
Log.d("rxble","no locate permission" );
case BLUETOOTH_NOT_ENABLED:
// scanning and connecting will not work
Log.d("rxble","Bluetooth not enabled" );
case LOCATION_SERVICES_NOT_ENABLED:
// scanning will not work
Log.d("rxble","location services not enabled" );
default:
return Observable.empty();
}
})
.timeout(10, TimeUnit.SECONDS)
.subscribe(
rxBleScanResult -> {
device = rxBleScanResult.getBleDevice(); // get device to use later
String sc = rxBleScanResult.toString();
Log.d("rxble","scan result:"+rxBleScanResult.getBleDevice().getMacAddress()+" " + sc); // Process scan result here.
flowDisposable.dispose(); // dispose after use
},
throwable -> {
// Handle an error here.
Log.d("rxble","scan error" + throwable.getMessage());
flowDisposable.dispose(); // dispose after error
}
);
enter code here
因此在扫描结果后立即处理并保存扫描的设备。然后我尝试使用以下代码读取特征：
UUID uuid = UUID.fromString(PIN_UUID);
Log.d("rxble","trying to read characteristic:"+uuid );
if (disposable!=null) // dispose first if was not disposed
if (!disposable.isDisposed()) {
disposable.dispose();
}
disposable = device.establishConnection(false)
.flatMapSingle(rxBleConnection -> rxBleConnection.readCharacteristic(uuid))
.subscribe(
characteristicValue -> {
// Read characteristic value.
Log.d("rxble","read value:" + new String(characteristicValue));
disposable.dispose(); //dispose after use
},
throwable -> {
Log.d("rxble","read error" + throwable.getMessage());
disposable.dispose(); // dispose after error
}
);
但是这失败了，并在 logcat 中出现错误：
2021-06-22 11:54:55.495 25353-26152/heikki.fi.bttest D/rxble: read errorGATT exception from MAC address 84:CC:A8:2E:24:6A, with type BleGattOperation{description='SERVICE_DISCOVERY'}
看来我必须先做服务发现，但是怎么做？