Android Bluetooth Low Energy (BLE) - cozinhando da maneira certa, parte 4 (ligação)

Conteúdo

Parte # 1 (digitalização)

Parte # 2 (conectando / desconectando)

Parte # 3 (leitura / gravação)

Parte # 4 (ligação), você está aqui

No  artigo anterior,  descobrimos as operações de leitura / gravação, habilitar / desabilitar notificações e comandos de fila. Neste artigo, falaremos sobre  dispositivos de emparelhamento  ( Nota do tradutor - posteriormente usarei o termo "vinculação" ).

União

Alguns dispositivos requerem ligação para funcionar corretamente. Tecnicamente, isso significa que as chaves de criptografia são geradas, trocadas e armazenadas para uma troca segura de dados. Ao iniciar o procedimento de vinculação, o Android pode solicitar ao usuário consentimento, código PIN ou senha. Nas próximas conexões, o Android já sabe que o dispositivo está emparelhado e as chaves de criptografia são trocadas secretamente, sem intervenção do usuário. O uso de vínculo torna a conexão com o dispositivo mais segura porque a conexão é criptografada.

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. , iOS  CoreBluetooth



  !  createBond()



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bonding:

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Bonding

bonding ,  onConnectionStateChange



  bonding  BOND_BONDING



. bonding   ,  discoverServices()



, bonding ! .  onConnectionStateChanged



:

// Take action depending on the bond state
if(bondstate == BOND_NONE || bondstate == BOND_BONDED) {
    // Connected to device, now proceed to discover it's services
    ... 
} else if (bondstate == BOND_BONDING) {
    // Bonding process has already started let it complete
    Log.i(TAG, "waiting for bonding to complete");
}
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

, bonding,  BroadcastReceiver



   ACTION_BOND_STATE_CHANGED



   connectGatt



. bonding.

context.registerReceiver(bondStateReceiver, 
                        new IntentFilter(ACTION_BOND_STATE_CHANGED));
private final BroadcastReceiver bondStateReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        final String action = intent.getAction();
        final BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

        // Ignore updates for other devices
        if (bluetoothGatt == null || !device.getAddress().equals(bluetoothGatt.getDevice().getAddress()))
            return;

        // Check if action is valid
        if(action == null) return;

        // Take action depending on new bond state
        if (action.equals(ACTION_BOND_STATE_CHANGED)) {
            final int bondState = intent.getIntExtra(EXTRA_BOND_STATE, ERROR);
            final int previousBondState = intent.getIntExtra(BluetoothDevice.EXTRA_PREVIOUS_BOND_STATE, -1);

            switch (bondState) {
                case BOND_BONDING:
                    // Bonding started
                    ...
                    break;
                case BOND_BONDED:
                    // Bonding succeeded
                    ...
                    break;
                case BOND_NONE:
                    // Oh oh
                    ...
                    break;
            }
        }
    }
};
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

bonding, (service discovery), , :

case BOND_BONDED:
    // Bonding succeeded
    Log.d(TAG, "bonded");

    // Check if there are services
    if(bluetoothGatt.getServices().isEmpty()) {
        // No services discovered yet
        bleHandler.post(new Runnable() {
            @Override
            public void run() {
                Log.d(TAG, String.format("discovering services of '%s'", getName()));
                boolean result = bluetoothGatt.discoverServices();
                if (!result) {
                    Log.e(TAG, "discoverServices failed to start");
                }
            }
        });
    }
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

, bonding .

Bonding /

bonding / , /  GATT_INSUFFICIENT_AUTHENTICATION



. Android-6, 7  onCharacteristicRead



/onCharacteristicWrite



, bonding Android. Android-8 Android bonding. Android-6, 7 / . , bonding.

, :

public void onCharacteristicRead(BluetoothGatt gatt, final BluetoothGattCharacteristic characteristic, int status) {
    // Perform some checks on the status field
    if (status != GATT_SUCCESS) {
        if (status == GATT_INSUFFICIENT_AUTHENTICATION ) {
            // Characteristic encrypted and needs bonding,
            // So retry operation after bonding completes
            // This only happens on Android 5/6/7
            Log.w(TAG, "read needs bonding, bonding in progress");
            return;
        } else {
            Log.e(TAG, String.format(Locale.ENGLISH,"ERROR: Read failed for characteristic: %s, status %d", characteristic.getUuid(), status));
            completedCommand();
            return;
        }
    }
...
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

bonding , :

case BOND_BONDED:
    // Bonding succeeded
    Log.d(TAG, "bonded");

    // Check if there are services
    ...
    // If bonding was triggered by a read/write, we must retry it
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) {
        if (commandQueueBusy && !manuallyBonding) {
            bleHandler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    Log.d(TAG, "retrying command after bonding");
                    retryCommand();
                }
            }, 50);
        }
    }
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

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,  createBond



 , , . , ? iOS  createBond()



, – bonding , iOS. iOS. BLE ,  createBond()



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 createBond



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 createBond()



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  MAC-, (bonding). … ! (. : , , , ).

bonding

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.

, bonding . ,  removeBond()



, Java:

try {
    Method method = device.getClass().getMethod("removeBond", (Class[]) null);
    result = (boolean) method.invoke(device, (Object[]) null);
    if (result) {
        Log.i(TAG, "Successfully removed bond");
    }
    return result;
} catch (Exception e) {
    Log.e(TAG, "ERROR: could not remove bond");
    e.printStackTrace();
    return false;
}
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

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• bonding

  
  
  
  
  

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bonding BOND_NONE



   BroadcastReceiver



. bonding, :

case BOND_NONE:
    if(previousBondState == BOND_BONDING) {
       // Bonding failed
       ...
    } else {
       // Bond lost
       ...
    }
    disconnect();
    break;
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

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, . bonding,     , Bluetooth . bonding, Android , , . .

Pairing

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• ;

  
  
  
  
  

• ;

  
  
  
  
  

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• Bluetooth .

  
  
  
  
  

«»   60 . ,   . , , . , . UI -! () ! Samsung - ( JustWorks) , . PIN- . . !

, , , . , . :

public void startPairingPopupHack() {
    String manufacturer = Build.MANUFACTURER;
    if(!manufacturer.equals("samsung")) {
        bluetoothAdapter.startDiscovery();

        callBackHandler.postDelayed(new Runnable() {
            @Override
            public void run() {
                Log.d(TAG, "popup hack completed");
                bluetoothAdapter.cancelDiscovery();
            }
        }, 1000);
    }
}
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

– BLE . .

, bonding !

…

BLE Android (. : -, BLE Android, ). BLE . BLE, . !

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