Android BLE 从不接收来自特性的通知
Android BLE never receiving notifications from characteristics
我已经苦苦挣扎了一段时间，试图让我的 BLE 设备与我的 android 应用程序通信。
首先，这是我的 BLE 处理的完整代码：
BleCentral.java
import java.util.HashMap;
import java.util.function.Supplier;
import android.util.Log;
import android.content.Context;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothManager;
public class BleCentral
{
private HashMap<String, BluetoothGatt> m_connectedDevices;
public BleCentral()
{
m_connectedDevices = new HashMap<>();
}
private BluetoothAdapter m_GetAdapter(Context ctx)
{
final BluetoothManager bleMgr = (BluetoothManager)(ctx.getSystemService(Context.BLUETOOTH_SERVICE));
BluetoothAdapter adapter = bleMgr.getAdapter();
if (adapter == null || !adapter.isEnabled())
{
Log.e("BLE Central", "BLE either not available or not enabled. Please do something about it.");
return null;
}
return adapter;
}
public BluetoothDevice GetDevice(Context ctx, String address)
{
return m_GetAdapter(ctx).getRemoteDevice(address);
}
public <T extends BlePeripheral>
T Connect(Context ctx, String address, Supplier<T> supplier)
{
BluetoothDevice device = GetDevice(ctx, address);
T result = supplier.get();
m_connectedDevices.put(address, device.connectGatt(ctx, false, result, BluetoothDevice.TRANSPORT_LE));
return result;
}
}
BlePeripheral.java
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.UUID;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattDescriptor;
import android.os.Build;
import android.os.Handler;
import android.util.Log;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattService;
public abstract class BlePeripheral
extends BluetoothGattCallback
{
private final String kCCC_DESCRIPTOR_UUID = "00002902-0000-1000-8000-00805f9b34fb";
private Handler m_handler;
private boolean m_deviceReady;
private BluetoothGatt m_bluetoothGatt;
private Queue<CmdQueueItem> m_cmdQueue;
private boolean m_cmdQueueProcessing;
// ------------------------------------------------------------------------
// -- Own methods
protected BlePeripheral()
{
m_handler = new Handler();
m_deviceReady = false;
m_bluetoothGatt = null;
m_cmdQueue = new LinkedList<>();
m_cmdQueueProcessing = false;
}
public boolean IsDeviceReady()
{ return m_deviceReady; }
public void EnableNotifications(UUID service, UUID characteristic)
{ EnqueueSetNotificationForCharacteristic(m_bluetoothGatt.getService(service).getCharacteristic(characteristic), true); }
public void DisableNotifications(UUID service, UUID characteristic)
{ EnqueueSetNotificationForCharacteristic(m_bluetoothGatt.getService(service).getCharacteristic(characteristic), false); }
protected void WriteCharacteristic(UUID service, UUID characteristic, byte[] value, boolean requestResponse)
{ EnqueueWriteCharacteristic(m_bluetoothGatt.getService(service).getCharacteristic(characteristic), value, requestResponse); }
protected void ReadCharacteristic(UUID service, UUID characteristic)
{ EnqueueReadCharacteristic(m_bluetoothGatt.getService(service).getCharacteristic(characteristic)); }
// ------------------------------------------------------------------------
// -- BluetoothGattCallback overrides
@Override
public void onConnectionStateChange(final BluetoothGatt gatt, int status, int newState)
{
super.onConnectionStateChange(gatt, status, newState);
final BluetoothDevice device = gatt.getDevice();
switch (status)
{
case 133: /* GATT_ERROR */
Log.e("BLE", "GATT_ERROR");
gatt.close();
try { Thread.sleep(150); }
catch (InterruptedException e) { e.printStackTrace(); }
break;
case 0: /* GATT_SUCCESS */
switch (newState)
{
case BluetoothGatt.STATE_CONNECTED:
Log.i("BLE", "Connected to " + device.getAddress() + " (" + device.getName() + ")");
m_bluetoothGatt = gatt;
int delayWhenBonded = (Build.VERSION.SDK_INT <= Build.VERSION_CODES.N) ? 2000 : 0;
switch (device.getBondState())
{
case BluetoothDevice.BOND_NONE:
delayWhenBonded = 0;
case BluetoothDevice.BOND_BONDED:
m_handler.postDelayed(new Runnable() {
@Override
public void run() {
boolean result = gatt.discoverServices();
if (!result)
Log.e("BLE", "discoverServices() failed to start");
}
}, delayWhenBonded);
break;
case BluetoothDevice.BOND_BONDING:
Log.i("BLE", "Waiting for bonding to complete");
break;
}
break;
case BluetoothGatt.STATE_DISCONNECTED:
gatt.close();
break;
}
break;
}
}
@Override
public void onServicesDiscovered(BluetoothGatt gatt, int status)
{
super.onServicesDiscovered(gatt, status);
if (status == 129 /* GATT_INTERNAL_ERROR */)
{
Log.e("BLE", "Service discovery failed");
gatt.disconnect();
return;
}
final List<BluetoothGattService> services = gatt.getServices();
Log.i("BLE", "Discovered " + services.size() + " services for " + gatt.getDevice().getAddress());
m_deviceReady = SetupDevice(gatt);
if (!m_deviceReady)
Log.e("BLE", "Peripheral does not comply to this device's requirements");
}
@Override
public void onCharacteristicChanged(BluetoothGatt gatt, final BluetoothGattCharacteristic characteristic)
{
super.onCharacteristicChanged(gatt, characteristic);
Log.i("BLE", "onCharacteristicChanged: " + characteristic.getUuid());
final byte[] value = new byte[characteristic.getValue().length];
System.arraycopy(characteristic.getValue(), 0, value, 0, characteristic.getValue().length);
OnUpdate(characteristic.getService().getUuid(), characteristic.getUuid(), value);
}
@Override
public void onCharacteristicRead(BluetoothGatt gatt, final BluetoothGattCharacteristic characteristic, int status)
{
super.onCharacteristicRead(gatt, characteristic, status);
ProcessCmdQueue();
Log.i("BLE", "onCharacteristicRead: " + characteristic.getUuid());
final byte[] value = new byte[characteristic.getValue().length];
System.arraycopy(characteristic.getValue(), 0, value, 0, characteristic.getValue().length);
OnUpdate(characteristic.getService().getUuid(), characteristic.getUuid(), value);
}
@Override
public void onCharacteristicWrite(BluetoothGatt gatt, final BluetoothGattCharacteristic characteristic, int status)
{
super.onCharacteristicWrite(gatt, characteristic, status);
ProcessCmdQueue();
Log.i("BLE", "onCharacteristicWrite: " + characteristic.getUuid());
}
@Override
public void onDescriptorWrite(BluetoothGatt gatt, final BluetoothGattDescriptor descriptor, final int status)
{
super.onDescriptorWrite(gatt, descriptor, status);
ProcessCmdQueue();
final BluetoothGattCharacteristic parentCharacteristic = descriptor.getCharacteristic();
if(status != 0 /* GATT_SUCCESS */)
{
Log.e("BLE", "WriteDescriptor failed for characteristic " + parentCharacteristic.getUuid());
return;
}
if(descriptor.getUuid().equals(UUID.fromString(kCCC_DESCRIPTOR_UUID)))
{
if(status == 0 /* GATT_SUCCESS */)
{
byte[] value = descriptor.getValue();
if (value != null)
{
if (value[0] != 0)
Log.i("BLE", "Characteristic " + parentCharacteristic.getUuid() + " is now notifying");
else
Log.i("BLE", "Characteristic " + parentCharacteristic.getUuid() + " is now NOT notifying");
}
}
}
}
// ------------------------------------------------------------------------
// -- Command Queue implementation
/* An enqueueable write operation - notification subscription or characteristic write */
private class CmdQueueItem
{
BluetoothGattCharacteristic characteristic;
byte[] dataToWrite; // Only used for characteristic write
boolean writeWoRsp; // Only used for characteristic write
boolean enabled; // Only used for characteristic notification subscription
public m_queueItemType type;
}
private enum m_queueItemType
{
SubscribeCharacteristic,
ReadCharacteristic,
WriteCharacteristic
}
/* queues enables/disables notification for characteristic */
public void EnqueueSetNotificationForCharacteristic(BluetoothGattCharacteristic ch, boolean enabled)
{
// Add to queue because shitty Android GATT stuff is only synchronous
CmdQueueItem m_queueItem = new CmdQueueItem();
m_queueItem.characteristic = ch;
m_queueItem.enabled = enabled;
m_queueItem.type = m_queueItemType.SubscribeCharacteristic;
EnqueueBleCommand(m_queueItem);
}
/* queues enables/disables notification for characteristic */
public void EnqueueWriteCharacteristic(final BluetoothGattCharacteristic ch, final byte[] dataToWrite, boolean requestResponse)
{
// Add to queue because shitty Android GATT stuff is only synchronous
CmdQueueItem m_queueItem = new CmdQueueItem();
m_queueItem.characteristic = ch;
m_queueItem.dataToWrite = dataToWrite;
m_queueItem.writeWoRsp = !requestResponse;
m_queueItem.type = m_queueItemType.WriteCharacteristic;
EnqueueBleCommand(m_queueItem);
}
/* request to fetch newest value stored on the remote device for particular characteristic */
public void EnqueueReadCharacteristic(BluetoothGattCharacteristic ch)
{
// Add to queue because shitty Android GATT stuff is only synchronous
CmdQueueItem m_queueItem = new CmdQueueItem();
m_queueItem.characteristic = ch;
m_queueItem.type = m_queueItemType.ReadCharacteristic;
EnqueueBleCommand(m_queueItem);
}
/**
* Add a transaction item to transaction queue
* @param m_queueItem
*/
private void EnqueueBleCommand(CmdQueueItem m_queueItem)
{
m_cmdQueue.add(m_queueItem);
// If there is no other transmission processing, go do this one!
if (!m_cmdQueueProcessing)
ProcessCmdQueue();
}
/**
* Call when a transaction has been completed.
* Will process next transaction if queued
*/
private void ProcessCmdQueue()
{
if (m_cmdQueue.size() <= 0)
{
m_cmdQueueProcessing = false;
return;
}
m_cmdQueueProcessing = true;
CmdQueueItem m_queueItem = m_cmdQueue.remove();
switch (m_queueItem.type)
{
case WriteCharacteristic:
writeDataToCharacteristic(m_queueItem.characteristic, m_queueItem.dataToWrite, m_queueItem.writeWoRsp);
break;
case SubscribeCharacteristic:
setNotificationForCharacteristic(m_queueItem.characteristic, m_queueItem.enabled);
break;
case ReadCharacteristic:
requestCharacteristicValue(m_queueItem.characteristic);
break;
}
}
public void requestCharacteristicValue(BluetoothGattCharacteristic ch)
{
if (m_bluetoothGatt == null)
return;
m_bluetoothGatt.readCharacteristic(ch);
}
private void writeDataToCharacteristic(final BluetoothGattCharacteristic ch, final byte[] dataToWrite, boolean writeWoRsp)
{
if (m_bluetoothGatt == null || ch == null)
return;
ch.setValue(dataToWrite);
ch.setWriteType(writeWoRsp ? BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE : BluetoothGattCharacteristic.WRITE_TYPE_DEFAULT);
m_bluetoothGatt.writeCharacteristic(ch);
}
/* enables/disables notification for characteristic */
private void setNotificationForCharacteristic(BluetoothGattCharacteristic ch, boolean enabled)
{
if (m_bluetoothGatt == null || ch == null)
return;
ch.setWriteType(BluetoothGattCharacteristic.WRITE_TYPE_DEFAULT);
boolean success = m_bluetoothGatt.setCharacteristicNotification(ch, enabled);
if(success)
{
// This is also sometimes required (e.g. for heart rate monitors) to enable notifications/indications
// see: https://developer.bluetooth.org/gatt/descriptors/Pages/DescriptorViewer.aspx?u=org.bluetooth.descriptor.gatt.client_characteristic_configuration.xml
BluetoothGattDescriptor descriptor = ch.getDescriptor(UUID.fromString("00002902-0000-1000-8000-00805f9b34fb"));
if(descriptor != null)
{
if (enabled)
descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
else
descriptor.setValue(BluetoothGattDescriptor.DISABLE_NOTIFICATION_VALUE);
if (m_bluetoothGatt.writeDescriptor(descriptor))
{
Log.i("BLE Peripheral", "SetNotification (Set + CCC) succeeded!");
}
}
else
Log.i("BLE Peripheral", "SetNotification (Set only) succeeded!");
}
else
Log.e("BLE Peripheral", "SetNotification failed!");
}
// ------------------------------------------------------------------------
// -- Abstract methods
protected abstract boolean SetupDevice(BluetoothGatt gatt);
protected abstract void OnUpdate(UUID service, UUID characteristic, final byte[] value);
}
用于创建和连接到设备的代码
BleCentral central = new BleCentral();
m_customDevice = central.Connect(this, deviceMacAddress, () -> new CustomDevice());
CustomDevice 只是继承了 BlePeripheral class，实现了 SetupDevice（检查所有服务和特性是否存在）和 OnUpdate（接收新数据并处理它）。
现在，有两件事困扰着我：
当连接到设备时，有时它可以立即工作，有时则不能。如果没有，我必须通过另一个应用程序（例如 Bluefruit Connect）连接到设备，然后再次启动我的应用程序，然后它就会连接；
当它连接时，它会进行服务发现和所有操作，并且在 setNotificationForCharacteristic 函数中一切都被正确调用（我调用了 onDescriptorWrite 和所有操作）但我从未收到任何通知。
因为我是 BLE 外围设备上代码 运行 的幕后黑手，所以我可以保证我试图从中获取数据的特征是 NOTIFY 类型（而不是例如 INDICATE）。
如果它能以任何方式提供帮助，唯一的 NOTIFY 特性就是尽可能频繁地发送一个 56 字节的数组，其中填充了 14 个浮点数。使用 Web Bluetooth 或 NativeScript（使用 nativescript-bluetooth 插件）的早期原型向我展示了这确实有效，在这些情况下，我大约每 90 毫秒得到一次结果。
我想我已经将这段代码重写了大约 3 次，我有点绝望了，所以任何朝着正确方向前进的帮助都将不胜感激。 :D
非常感谢！
Edit：为了科学，我尝试在设备上将特性切换为 READ 特性，然后生成线程读取每秒发送一次，而不是等待通知。好吧，调用了 onCharacteristicRead，但是传递给它的字节数组的长度始终为零...
我发现了问题 - 它与 Java 代码根本无关，而是由于我的 BLE 设备中的硬件故障导致所有值更新被丢弃。
我已经苦苦挣扎了一段时间，试图让我的 BLE 设备与我的 android 应用程序通信。
首先，这是我的 BLE 处理的完整代码：
BleCentral.java
import java.util.HashMap;
import java.util.function.Supplier;
import android.util.Log;
import android.content.Context;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothManager;
public class BleCentral
{
private HashMap<String, BluetoothGatt> m_connectedDevices;
public BleCentral()
{
m_connectedDevices = new HashMap<>();
}
private BluetoothAdapter m_GetAdapter(Context ctx)
{
final BluetoothManager bleMgr = (BluetoothManager)(ctx.getSystemService(Context.BLUETOOTH_SERVICE));
BluetoothAdapter adapter = bleMgr.getAdapter();
if (adapter == null || !adapter.isEnabled())
{
Log.e("BLE Central", "BLE either not available or not enabled. Please do something about it.");
return null;
}
return adapter;
}
public BluetoothDevice GetDevice(Context ctx, String address)
{
return m_GetAdapter(ctx).getRemoteDevice(address);
}
public <T extends BlePeripheral>
T Connect(Context ctx, String address, Supplier<T> supplier)
{
BluetoothDevice device = GetDevice(ctx, address);
T result = supplier.get();
m_connectedDevices.put(address, device.connectGatt(ctx, false, result, BluetoothDevice.TRANSPORT_LE));
return result;
}
}
BlePeripheral.java
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.UUID;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattDescriptor;
import android.os.Build;
import android.os.Handler;
import android.util.Log;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattService;
public abstract class BlePeripheral
extends BluetoothGattCallback
{
private final String kCCC_DESCRIPTOR_UUID = "00002902-0000-1000-8000-00805f9b34fb";
private Handler m_handler;
private boolean m_deviceReady;
private BluetoothGatt m_bluetoothGatt;
private Queue<CmdQueueItem> m_cmdQueue;
private boolean m_cmdQueueProcessing;
// ------------------------------------------------------------------------
// -- Own methods
protected BlePeripheral()
{
m_handler = new Handler();
m_deviceReady = false;
m_bluetoothGatt = null;
m_cmdQueue = new LinkedList<>();
m_cmdQueueProcessing = false;
}
public boolean IsDeviceReady()
{ return m_deviceReady; }
public void EnableNotifications(UUID service, UUID characteristic)
{ EnqueueSetNotificationForCharacteristic(m_bluetoothGatt.getService(service).getCharacteristic(characteristic), true); }
public void DisableNotifications(UUID service, UUID characteristic)
{ EnqueueSetNotificationForCharacteristic(m_bluetoothGatt.getService(service).getCharacteristic(characteristic), false); }
protected void WriteCharacteristic(UUID service, UUID characteristic, byte[] value, boolean requestResponse)
{ EnqueueWriteCharacteristic(m_bluetoothGatt.getService(service).getCharacteristic(characteristic), value, requestResponse); }
protected void ReadCharacteristic(UUID service, UUID characteristic)
{ EnqueueReadCharacteristic(m_bluetoothGatt.getService(service).getCharacteristic(characteristic)); }
// ------------------------------------------------------------------------
// -- BluetoothGattCallback overrides
@Override
public void onConnectionStateChange(final BluetoothGatt gatt, int status, int newState)
{
super.onConnectionStateChange(gatt, status, newState);
final BluetoothDevice device = gatt.getDevice();
switch (status)
{
case 133: /* GATT_ERROR */
Log.e("BLE", "GATT_ERROR");
gatt.close();
try { Thread.sleep(150); }
catch (InterruptedException e) { e.printStackTrace(); }
break;
case 0: /* GATT_SUCCESS */
switch (newState)
{
case BluetoothGatt.STATE_CONNECTED:
Log.i("BLE", "Connected to " + device.getAddress() + " (" + device.getName() + ")");
m_bluetoothGatt = gatt;
int delayWhenBonded = (Build.VERSION.SDK_INT <= Build.VERSION_CODES.N) ? 2000 : 0;
switch (device.getBondState())
{
case BluetoothDevice.BOND_NONE:
delayWhenBonded = 0;
case BluetoothDevice.BOND_BONDED:
m_handler.postDelayed(new Runnable() {
@Override
public void run() {
boolean result = gatt.discoverServices();
if (!result)
Log.e("BLE", "discoverServices() failed to start");
}
}, delayWhenBonded);
break;
case BluetoothDevice.BOND_BONDING:
Log.i("BLE", "Waiting for bonding to complete");
break;
}
break;
case BluetoothGatt.STATE_DISCONNECTED:
gatt.close();
break;
}
break;
}
}
@Override
public void onServicesDiscovered(BluetoothGatt gatt, int status)
{
super.onServicesDiscovered(gatt, status);
if (status == 129 /* GATT_INTERNAL_ERROR */)
{
Log.e("BLE", "Service discovery failed");
gatt.disconnect();
return;
}
final List<BluetoothGattService> services = gatt.getServices();
Log.i("BLE", "Discovered " + services.size() + " services for " + gatt.getDevice().getAddress());
m_deviceReady = SetupDevice(gatt);
if (!m_deviceReady)
Log.e("BLE", "Peripheral does not comply to this device's requirements");
}
@Override
public void onCharacteristicChanged(BluetoothGatt gatt, final BluetoothGattCharacteristic characteristic)
{
super.onCharacteristicChanged(gatt, characteristic);
Log.i("BLE", "onCharacteristicChanged: " + characteristic.getUuid());
final byte[] value = new byte[characteristic.getValue().length];
System.arraycopy(characteristic.getValue(), 0, value, 0, characteristic.getValue().length);
OnUpdate(characteristic.getService().getUuid(), characteristic.getUuid(), value);
}
@Override
public void onCharacteristicRead(BluetoothGatt gatt, final BluetoothGattCharacteristic characteristic, int status)
{
super.onCharacteristicRead(gatt, characteristic, status);
ProcessCmdQueue();
Log.i("BLE", "onCharacteristicRead: " + characteristic.getUuid());
final byte[] value = new byte[characteristic.getValue().length];
System.arraycopy(characteristic.getValue(), 0, value, 0, characteristic.getValue().length);
OnUpdate(characteristic.getService().getUuid(), characteristic.getUuid(), value);
}
@Override
public void onCharacteristicWrite(BluetoothGatt gatt, final BluetoothGattCharacteristic characteristic, int status)
{
super.onCharacteristicWrite(gatt, characteristic, status);
ProcessCmdQueue();
Log.i("BLE", "onCharacteristicWrite: " + characteristic.getUuid());
}
@Override
public void onDescriptorWrite(BluetoothGatt gatt, final BluetoothGattDescriptor descriptor, final int status)
{
super.onDescriptorWrite(gatt, descriptor, status);
ProcessCmdQueue();
final BluetoothGattCharacteristic parentCharacteristic = descriptor.getCharacteristic();
if(status != 0 /* GATT_SUCCESS */)
{
Log.e("BLE", "WriteDescriptor failed for characteristic " + parentCharacteristic.getUuid());
return;
}
if(descriptor.getUuid().equals(UUID.fromString(kCCC_DESCRIPTOR_UUID)))
{
if(status == 0 /* GATT_SUCCESS */)
{
byte[] value = descriptor.getValue();
if (value != null)
{
if (value[0] != 0)
Log.i("BLE", "Characteristic " + parentCharacteristic.getUuid() + " is now notifying");
else
Log.i("BLE", "Characteristic " + parentCharacteristic.getUuid() + " is now NOT notifying");
}
}
}
}
// ------------------------------------------------------------------------
// -- Command Queue implementation
/* An enqueueable write operation - notification subscription or characteristic write */
private class CmdQueueItem
{
BluetoothGattCharacteristic characteristic;
byte[] dataToWrite; // Only used for characteristic write
boolean writeWoRsp; // Only used for characteristic write
boolean enabled; // Only used for characteristic notification subscription
public m_queueItemType type;
}
private enum m_queueItemType
{
SubscribeCharacteristic,
ReadCharacteristic,
WriteCharacteristic
}
/* queues enables/disables notification for characteristic */
public void EnqueueSetNotificationForCharacteristic(BluetoothGattCharacteristic ch, boolean enabled)
{
// Add to queue because shitty Android GATT stuff is only synchronous
CmdQueueItem m_queueItem = new CmdQueueItem();
m_queueItem.characteristic = ch;
m_queueItem.enabled = enabled;
m_queueItem.type = m_queueItemType.SubscribeCharacteristic;
EnqueueBleCommand(m_queueItem);
}
/* queues enables/disables notification for characteristic */
public void EnqueueWriteCharacteristic(final BluetoothGattCharacteristic ch, final byte[] dataToWrite, boolean requestResponse)
{
// Add to queue because shitty Android GATT stuff is only synchronous
CmdQueueItem m_queueItem = new CmdQueueItem();
m_queueItem.characteristic = ch;
m_queueItem.dataToWrite = dataToWrite;
m_queueItem.writeWoRsp = !requestResponse;
m_queueItem.type = m_queueItemType.WriteCharacteristic;
EnqueueBleCommand(m_queueItem);
}
/* request to fetch newest value stored on the remote device for particular characteristic */
public void EnqueueReadCharacteristic(BluetoothGattCharacteristic ch)
{
// Add to queue because shitty Android GATT stuff is only synchronous
CmdQueueItem m_queueItem = new CmdQueueItem();
m_queueItem.characteristic = ch;
m_queueItem.type = m_queueItemType.ReadCharacteristic;
EnqueueBleCommand(m_queueItem);
}
/**
* Add a transaction item to transaction queue
* @param m_queueItem
*/
private void EnqueueBleCommand(CmdQueueItem m_queueItem)
{
m_cmdQueue.add(m_queueItem);
// If there is no other transmission processing, go do this one!
if (!m_cmdQueueProcessing)
ProcessCmdQueue();
}
/**
* Call when a transaction has been completed.
* Will process next transaction if queued
*/
private void ProcessCmdQueue()
{
if (m_cmdQueue.size() <= 0)
{
m_cmdQueueProcessing = false;
return;
}
m_cmdQueueProcessing = true;
CmdQueueItem m_queueItem = m_cmdQueue.remove();
switch (m_queueItem.type)
{
case WriteCharacteristic:
writeDataToCharacteristic(m_queueItem.characteristic, m_queueItem.dataToWrite, m_queueItem.writeWoRsp);
break;
case SubscribeCharacteristic:
setNotificationForCharacteristic(m_queueItem.characteristic, m_queueItem.enabled);
break;
case ReadCharacteristic:
requestCharacteristicValue(m_queueItem.characteristic);
break;
}
}
public void requestCharacteristicValue(BluetoothGattCharacteristic ch)
{
if (m_bluetoothGatt == null)
return;
m_bluetoothGatt.readCharacteristic(ch);
}
private void writeDataToCharacteristic(final BluetoothGattCharacteristic ch, final byte[] dataToWrite, boolean writeWoRsp)
{
if (m_bluetoothGatt == null || ch == null)
return;
ch.setValue(dataToWrite);
ch.setWriteType(writeWoRsp ? BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE : BluetoothGattCharacteristic.WRITE_TYPE_DEFAULT);
m_bluetoothGatt.writeCharacteristic(ch);
}
/* enables/disables notification for characteristic */
private void setNotificationForCharacteristic(BluetoothGattCharacteristic ch, boolean enabled)
{
if (m_bluetoothGatt == null || ch == null)
return;
ch.setWriteType(BluetoothGattCharacteristic.WRITE_TYPE_DEFAULT);
boolean success = m_bluetoothGatt.setCharacteristicNotification(ch, enabled);
if(success)
{
// This is also sometimes required (e.g. for heart rate monitors) to enable notifications/indications
// see: https://developer.bluetooth.org/gatt/descriptors/Pages/DescriptorViewer.aspx?u=org.bluetooth.descriptor.gatt.client_characteristic_configuration.xml
BluetoothGattDescriptor descriptor = ch.getDescriptor(UUID.fromString("00002902-0000-1000-8000-00805f9b34fb"));
if(descriptor != null)
{
if (enabled)
descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
else
descriptor.setValue(BluetoothGattDescriptor.DISABLE_NOTIFICATION_VALUE);
if (m_bluetoothGatt.writeDescriptor(descriptor))
{
Log.i("BLE Peripheral", "SetNotification (Set + CCC) succeeded!");
}
}
else
Log.i("BLE Peripheral", "SetNotification (Set only) succeeded!");
}
else
Log.e("BLE Peripheral", "SetNotification failed!");
}
// ------------------------------------------------------------------------
// -- Abstract methods
protected abstract boolean SetupDevice(BluetoothGatt gatt);
protected abstract void OnUpdate(UUID service, UUID characteristic, final byte[] value);
}
用于创建和连接到设备的代码
BleCentral central = new BleCentral();
m_customDevice = central.Connect(this, deviceMacAddress, () -> new CustomDevice());
CustomDevice 只是继承了 BlePeripheral class，实现了 SetupDevice（检查所有服务和特性是否存在）和 OnUpdate（接收新数据并处理它）。
现在，有两件事困扰着我：
当连接到设备时，有时它可以立即工作，有时则不能。如果没有，我必须通过另一个应用程序（例如 Bluefruit Connect）连接到设备，然后再次启动我的应用程序，然后它就会连接；
当它连接时，它会进行服务发现和所有操作，并且在 setNotificationForCharacteristic 函数中一切都被正确调用（我调用了 onDescriptorWrite 和所有操作）但我从未收到任何通知。
因为我是 BLE 外围设备上代码 运行 的幕后黑手，所以我可以保证我试图从中获取数据的特征是 NOTIFY 类型（而不是例如 INDICATE）。
如果它能以任何方式提供帮助，唯一的 NOTIFY 特性就是尽可能频繁地发送一个 56 字节的数组，其中填充了 14 个浮点数。使用 Web Bluetooth 或 NativeScript（使用 nativescript-bluetooth 插件）的早期原型向我展示了这确实有效，在这些情况下，我大约每 90 毫秒得到一次结果。
我想我已经将这段代码重写了大约 3 次，我有点绝望了，所以任何朝着正确方向前进的帮助都将不胜感激。 :D
非常感谢！
Edit：为了科学，我尝试在设备上将特性切换为 READ 特性，然后生成线程读取每秒发送一次，而不是等待通知。好吧，调用了 onCharacteristicRead，但是传递给它的字节数组的长度始终为零...
我发现了问题 - 它与 Java 代码根本无关，而是由于我的 BLE 设备中的硬件故障导致所有值更新被丢弃。