Android BLE 连接和断开快速读取 1 个特征。一些BLE设备在快速连接断开后停止广播

Question

我正在尝试编写扫描 BLE 设备的 android 应用程序，当它找到具有命名方案的某些设备时，它会连接到它并读取一个特征(用户定义的设备名称)，然后立即断开连接。然后它将在列表中显示该设备以及找到的任何其他设备并读取用户定义的名称。然后，用户可以选择要连接的设备(或多个设备)并连接到它并从中流式传输数据。

不断发生的问题是在它获得用户定义的名称并断开连接后，BLE 设备停止广播并且我在扫描时无法再找到它，或者如果我在读取用户定义的名称后尝试连接它并且断开连接。

这是 Android BLE 堆栈的问题还是我需要添加更多延迟(我在使用的整个蓝牙服务中有 100 毫秒的延迟)

这是我在服务中使用的部分代码

 public boolean initialize() {

    Log.i(TAG, "Initializing");
    try {
        synchronized (Thread.currentThread()) {
            Thread.currentThread().wait(100);
        }
    }catch(InterruptedException e){
        //ignore
    }
    if (mBluetoothManager == null) {
        mBluetoothManager = (BluetoothManager) getSystemService(BLUETOOTH_SERVICE);
        if (mBluetoothManager == null) {
            Log.e(TAG, "Unable to initialize BluetoothManager.");
            return false;
        }
    }

    mBluetoothAdapter = mBluetoothManager.getAdapter();
    if (mBluetoothAdapter == null) {
        Log.e(TAG, "Unable to obtain a BluetoothAdapter.");
        return false;
    }


    mReadyToWrite = true;
    mReadyToRead = true;
    mReady = true;
    mCharacteristicWriteQueue   = new ArrayDeque<BluetoothGattCharacteristic>();
    mCharacteristicReadQueue    = new ArrayDeque<BluetoothGattCharacteristic>();
    mDescriptorWriteQueue       = new ArrayDeque<BluetoothGattDescriptor>();
    mDescriptorReadQueue        = new ArrayDeque<BluetoothGattDescriptor>();

    //mBluetoothGattMap = new HashMap<String, BluetoothGatt>();
    return true;
}

/**
 * Connects to the GATT server hosted on the Bluetooth LE device.
 *
 * @param address The device address of the device.
 *
 * @return Return true if the connection is initiated successfully. The connection result
 *         is reported asynchronously through the
 *         {@code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
 *         callback.
 */
public boolean connect(final String address) {
    if (mBluetoothAdapter == null || address == null) {
        Log.w(TAG, "BluetoothAdapter not initialized or unspecified address.");
        return false;
    }



    if(mBluetoothGattMap.containsKey(address)) {
        Log.d(TAG, "Trying to use an existing mBluetoothGatt for connection.");
        if (mBluetoothGattMap.get(address).connect()) {
            mConnectionState = STATE_CONNECTING;
            return true;
        } else {
            return false;
        }
    }

    final BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
    if (device == null) {
        Log.w(TAG, "Device not found.  Unable to connect.");
        return false;
    }

    try {
        synchronized (Thread.currentThread()) {
            Thread.currentThread().wait(100);
        }
    }catch(InterruptedException e){
        //ignore
    }
    mBluetoothGattMap.put(address, device.connectGatt(this, false, mGattCallback));


    Log.d(TAG, "Trying to create a new connection to address " + address);
    //mBluetoothDeviceAddress = address;
    mConnectionState = STATE_CONNECTING;
    return true;
}

/**
 * Disconnects an existing connection or cancel a pending connection. The disconnection result
 * is reported asynchronously through the
 * {@code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
 * callback.
 */
public void disconnect(String address) {
    if (mBluetoothAdapter == null || !mBluetoothGattMap.containsKey(address)) {
        Log.w(TAG, "BluetoothAdapter not initialized");
        return;
    }
    Log.i(TAG, "Disconnecting from gatt");
    try {
        synchronized (Thread.currentThread()) {
            Thread.currentThread().wait(100);
        }
    }catch(InterruptedException e){
        //ignore
    }
    mBluetoothGattMap.get(address).disconnect();
}


public void close(String address) {
    try {
        synchronized (Thread.currentThread()) {
            Thread.currentThread().wait(100);
        }
    }catch(InterruptedException e){
        //ignore
    }
    mBluetoothGattMap.get(address).close();
    mBluetoothGattMap.remove(address);
    Log.w(TAG, "Succeeed removing it");
}

public int getConnectionState(String address) {
    Log.i(TAG, "getting connection state for " + address);
    BluetoothGatt gatt = mBluetoothGattMap.get(address);
    return mBluetoothManager.getConnectionState(gatt.getDevice(), BluetoothProfile.GATT);
}

/**
 * Request a read on a given {@code BluetoothGattCharacteristic}. The read result is reported
 * asynchronously through the {@code BluetoothGattCallback#onCharacteristicRead(android.bluetooth.BluetoothGatt, android.bluetooth.BluetoothGattCharacteristic, int)}
 * callback.
 *
 * @param characteristic The characteristic to read from.
 */
public void readCharacteristic(String address, BluetoothGattCharacteristic characteristic) {
    Log.i(TAG, "reading characteristic");
    if (mBluetoothAdapter == null || !mBluetoothGattMap.containsKey(address)) {
        Log.w(TAG, "BluetoothAdapter not initialized");
        return;
    }
    try {
        synchronized (Thread.currentThread()) {
            Thread.currentThread().wait(100);
        }
    }catch(InterruptedException e){
        //ignore
    }
    if(mReadyToRead && mReady) {
        boolean result = mBluetoothGattMap.get(address).readCharacteristic(characteristic);
        mReadyToRead = false;
        mReady = false;
        if(!result) {
            Log.i(TAG, "read failed");
        }
    }else {
        mCharacteristicReadQueue.push(characteristic);
    }
}

public void writeCharacteristic(String address, BluetoothGattCharacteristic characteristic) {
    Log.i(TAG, "writeCharacteristic - readyToWrite = " + mReadyToWrite + " queue size = " + mCharacteristicWriteQueue.size());
    if (mBluetoothAdapter == null || !mBluetoothGattMap.containsKey(address)) {
        Log.w(TAG, "BluetoothAdapter not initialized");
        return;
    }
    try {
        synchronized (Thread.currentThread()) {
            Thread.currentThread().wait(100);
        }
    }catch(InterruptedException e){
        //ignore
    }
    if(mReadyToWrite && mReady) {
        boolean result = mBluetoothGattMap.get(address).writeCharacteristic(characteristic);
        mReadyToWrite = false;
        mReady = false;
        if(!result) {
            Log.i(TAG, "characteristic write failed");
        }
    }else {
        mCharacteristicWriteQueue.push(characteristic);
    }
}

public void readDescriptor(String address, BluetoothGattDescriptor descriptor) {
    Log.i(TAG, "reading descriptor");
    if (mBluetoothAdapter == null || !mBluetoothGattMap.containsKey(address)) {
        Log.w(TAG, "BluetoothAdapter not initialized");
        return;
    }
    try {
        synchronized (Thread.currentThread()) {
            Thread.currentThread().wait(100);
        }
    }catch(InterruptedException e){
        //ignore
    }
    if(mReadyToRead && mReady) {
        boolean result = mBluetoothGattMap.get(address).readDescriptor(descriptor);
        mReadyToRead = false;
        mReady = false;
        if(!result) {
            Log.i(TAG, "descriptor read failed");
        }
    }else {
        mDescriptorReadQueue.push(descriptor);
    }
}

public void writeDescriptor(String address, BluetoothGattDescriptor descriptor) {
    Log.i(TAG, "writing descriptor for characteristic " + descriptor.getCharacteristic().getUuid().toString());
    if (mBluetoothAdapter == null || !mBluetoothGattMap.containsKey(address)) {
        Log.w(TAG, "BluetoothAdapter not initialized");
        return;
    }
    try {
        synchronized (Thread.currentThread()) {
            Thread.currentThread().wait(100);
        }
    }catch(InterruptedException e){
        //ignore
    }
    if(mReadyToWrite && mReady) {
        boolean result = mBluetoothGattMap.get(address).writeDescriptor(descriptor);
        mReadyToWrite = false;
        mReady = false;
        if(!result) {
            Log.i(TAG, "descriptor write failed");
        }
    }else {
        mDescriptorWriteQueue.push(descriptor);
    }
}

public BluetoothGattCharacteristic getCharacteristic(String address, UUID uuid) {
    if(!mBluetoothGattMap.containsKey(address)) {
        Log.i(TAG, "Device address " + address + " not found");
        return null;
    }
    try {
        synchronized (Thread.currentThread()) {
            Thread.currentThread().wait(100);
        }
    }catch(InterruptedException e){
        //ignore
    }
    for(BluetoothGattService service : mBluetoothGattMap.get(address).getServices()) {
        Log.i(TAG, "Service: " + service.getUuid().toString());
        for (BluetoothGattCharacteristic characteristic : service.getCharacteristics()) {
            Log.i(TAG, "Characteristic: " + characteristic.getUuid().toString());
            if(characteristic.getUuid().equals(uuid)) {
                return characteristic;
            }
        }
    }
    Log.i(TAG, "Characteristic not found");
    return null;
}

public Set<String> getConnectedDevices(){
    return this.mBluetoothGattMap.keySet();
}

/**
 * Enables or disables notification on a give characteristic.
 *
 * @param characteristic Characteristic to act on.
 * @param enabled If true, enable notification.  False otherwise.
 */
public void setCharacteristicNotification(String address, BluetoothGattCharacteristic characteristic, boolean enabled) {
    if (mBluetoothAdapter == null || !mBluetoothGattMap.containsKey(address)) {
        Log.w(TAG, "BluetoothAdapter not initialized");
        return;
    }
    try {
        synchronized (Thread.currentThread()) {
            Thread.currentThread().wait(100);
        }
    }catch(InterruptedException e){
        //ignore
    }
    mBluetoothGattMap.get(address).setCharacteristicNotification(characteristic, enabled);
    BluetoothGattDescriptor descriptor = characteristic.getDescriptor(UUID.fromString(GattAttributes.CLIENT_CHAR_CONFIG));
    if(descriptor != null) {
        boolean status = descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
        Log.i(TAG, "descriptor " + descriptor.getUuid().toString() + " setValue() status: " + status);
        Log.i(TAG, "descriptor value: " + descriptor.getValue());
        writeDescriptor(address, descriptor);
    }
}

public void setPhoneEvents(byte priorities) {
    for(String address : mBluetoothGattMap.keySet()) {
        BluetoothGattCharacteristic characteristic = getCharacteristic(address, UUID.fromString(GattAttributes.ALERT_ATTRIBUTE));
        if (characteristic != null) {
            byte prioritiesBuf[] = new byte[1];
            prioritiesBuf[0] = priorities;
            characteristic.setValue(prioritiesBuf);
            writeCharacteristic(address, characteristic);
            Log.i(TAG, String.format("Forwarded phone alert priorities: 0x%X", priorities));
        } else {
            Log.e(TAG, "Failed to get the Alert ID characteristic from Gatt Server for device address " + address);
        }
    }
}

/**
 * Retrieves a list of supported GATT services on the connected device. This should be
 * invoked only after {@code BluetoothGatt#discoverServices()} completes successfully.
 *
 * @return A {@code List} of supported services.
 */
public List<BluetoothGattService> getSupportedGattServices(String address) {
    if (mBluetoothGattMap.get(address) == null) return null;

    return mBluetoothGattMap.get(address).getServices();
}

Answer 1

The problem that keeps happening is after it gets the user defined name and is disconnected the BLE devices stop broadcasting and I can no longer find it when I scan or if I try to connect to it after I read the user defined name and disconnected to it.

您的 BLE 设备不应该在连接断开后立即开始广播吗？我还建议您可以让您的 BLE 设备宣传您的自定义服务而不是您的应用程序以连接然后读取特性；你只需使用“ScanFilter”来过滤掉你最喜欢的设备。您只需让低级代码执行此操作即可。