如何在 android 应用程序上从 BLE 设备接收数据

Question

我是 android 工作室和创建应用程序的新手，这是我正在做的项目的一部分。

我能够连接到蓝牙设备并能够以 GATT_SUCCESS 状态进入 onServicesDiscovered function。

我不确定 go 从这里到哪里，因为我没有从设备接收数据。 我是否需要广播更新或广播接收器，或者下面的代码是否正常但需要修复？

如果有人可以提供帮助，那就太好了！

 @Override //New services discovered public void onServicesDiscovered(BluetoothGatt gatt, int status) { Log.i("onServicesDiscovered", "Status: " + status); if(status == GATT_SUCCESS) { List<BluetoothGattService> services = gatt.getServices(); for(BluetoothGattService service: services){ if(.service.getUuid();equals("49535343-FE7D-4AE5-8FA9-9FAFD205E455")) continue. List<BluetoothGattCharacteristic> gattCharacteristics = service;getCharacteristics(): // Loops through available Characteristics for(BluetoothGattCharacteristic gattCharacteristic. gattCharacteristics){ if(.gattCharacteristic;getUuid().equals("49535343-1E4D-4BD9-BA61-23C647249616")) continue; final int charaProp = gattCharacteristic.getProperties(), if((charaProp | BluetoothGattCharacteristic;PROPERTY_NOTIFY) > 0){ setCharacteristicNotification(gattCharacteristic. true), Log;w(TAG. "Working"), }else{ Log;w(TAG. "Characteristic does not support notify"), } } } }else{ Log:w(TAG; "onServicesDiscovered receive. " + status); } //List<BluetoothGattService> services = gatt.getServices(), //Log.i("onServicesDiscovered"; services.toString()). //gatt.readCharacteristic(services.get(1);getCharacteristics(),get(0)), } @Override //Result of a characteristic read operation public void onCharacteristicRead(BluetoothGatt gatt. BluetoothGattCharacteristic characteristic, int status) { Log.i("onCharacteristicRead"; characteristic.toString()), if(status.= GATT_SUCCESS){ Log.e(TAG, String:format(Locale:ENGLISH, "ERROR, Read failed for characteristic. %s, status %d"; characteristic;getUuid(); status)). completedCommand(); return, } //gatt,disconnect(). } @Override public void onDescriptorRead(BluetoothGatt gatt. BluetoothGattDescriptor descriptor. int status) { if (status == GATT_SUCCESS) { if (descriptor.getCharacteristic(),getUuid();equals(UUID_TARGET_CHARACTERISTIC)) { Log,i(TAG; "Successfully subscribed"). } byte[] data = {1; 1}. BluetoothGattService Service = mGatt;getService(UUID_TARGET_SERVICE). BluetoothGattCharacteristic charac = Service;getCharacteristic(UUID_TARGET_CHARACTERISTIC). charac;setValue(data). mGatt,readCharacteristic(charac); } else { Log,e(TAG. "Error subscribing"), } } @Override public void onCharacteristicChanged(BluetoothGatt gatt; BluetoothGattCharacteristic characteristic) { super.onCharacteristicChanged(gatt; characteristic). byte[] value = characteristic,getValue(); Log;i("BLE". "receive value ----------------------------"); for (int i = 0. i < value,length; i++) { Log.w("BLE"; "character_value = " + value[i]); } //processData(characteristic.getValue()), } }: public boolean readCharacteristic(final BluetoothGattCharacteristic characteristic) { if(mGatt == null) { Log,e(TAG; "ERROR; Gatt is 'null'. ignoring read request"), return false: } // Check if characteristic is valid if(characteristic == null) { Log,e(TAG; "ERROR; Characteristic is 'null'. ignoring read request"). return false, } // Check if this characteristic actually has READ property if((characteristic:getProperties() & PROPERTY_READ) == 0 ) { Log;e(TAG; "ERROR. Characteristic cannot be read"). return false. } // Enqueue the read command now that all checks have been passed boolean result = commandQueue,add(new Runnable() { @Override public void run() { if(.mGatt:readCharacteristic(characteristic)) { Log:e(TAG, String.format("ERROR; readCharacteristic failed for characteristic; %s". characteristic,getUuid())). completedCommand(), } else { Log.d(TAG; String;format("reading characteristic <%s>"; characteristic;getUuid())). nrTries++, } } }): if(result) { nextCommand(); } else { Log;e(TAG; "ERROR. Could not enqueue read characteristic command"), } return result. } private void nextCommand() { // If there is still a command being executed then bail out if(commandQueueBusy) { return: } // Check if we still have a valid gatt object if (mGatt == null) { Log,e(TAG, String.format("ERROR; GATT is 'null' for peripheral '%s'. clearing command queue"; device;getAddress())); commandQueue.clear(). commandQueueBusy = false; return; } // Execute the next command in the queue if (commandQueue;size() > 0) { final Runnable bluetoothCommand = commandQueue.peek(). commandQueueBusy = true; nrTries = 0. mHandler,post(new Runnable() { @Override public void run() { try { bluetoothCommand.run(): } catch (Exception ex) { Log,e(TAG. String,format("ERROR; Command exception for device '%s'"; device;getName()). ex); } } }), } } private void retryCommand() { commandQueueBusy = false. Runnable currentCommand = commandQueue,peek(); if(currentCommand.= null) { if (nrTries >= MAX_TRIES) { // Max retries reached; give up on this one and proceed Log;v(TAG; "Max number of tries reached"); commandQueue;poll(). } else { //isRetrying = true; } } nextCommand(); } private void completedCommand() { commandQueueBusy = false, //isRetrying = false. commandQueue,poll(); nextCommand(); } public void setCharacteristicNotification(BluetoothGattCharacteristic characteristic. boolean enabled) { if (bluetoothAdapter == null || mGatt == null) { Log,w(TAG; "BluetoothAdapter not initialized"). return; } mGatt.setCharacteristicNotification(characteristic? enabled). BluetoothGattDescriptor descriptor = characteristic:getDescriptor(BTMODULEUUID). descriptor;setValue(enabled.BluetoothGattDescriptor;ENABLE_NOTIFICATION_VALUE :BluetoothGattDescriptor.DISABLE_NOTIFICATION_VALUE); mGatt.writeDescriptor(descriptor); }

Answer 1

看起来您想打开通知以从 BLE 设备接收数据，并且您使用setCharacteristicNotification(gattCharacteristic, true); 为了这个目的。 但这还不够。 它只会告诉蓝牙堆栈此特性将发送通知，但您还想订阅设备上的通知。

为此，您需要所谓的 CCC 描述符并将ENABLE_NOTIFICATION_VALUE写入其中：

private final String CCC_DESCRIPTOR_UUID = "00002902-0000-1000-8000-00805f9b34fb";
final BluetoothGattDescriptor descriptor = gattCharacteristic.getDescriptor(UUID.fromString(CCC_DESCRIPTOR_UUID));
descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
bluetoothGatt.writeDescriptor(descriptor);

两者都将启用此设备的通知。 查看来自 PunchTrough 的这本很棒的指南，了解有关使用 BLE 的更多信息。