Question

我正在使用Android Studio构建一个可以从设备BLE中读取值的应用。该设备有4项服务。第四项服务有3个特点。我想阅读第四项服务的所有特点。

此设备可以发送更多信息，因此我希望应用程序可以存储从设备BLE到达的所有信息。

所以这是我的代码：

@TargetApi(21)
public class BLEActivity extends BaseActivity {

    private BluetoothAdapter mBluetoothAdapter;
    private int REQUEST_ENABLE_BT = 1;
    private Handler mHandler;
    private static final long SCAN_PERIOD = 10000;
    private BluetoothLeScanner mLEScanner;
    private ScanSettings settings;
    private List<ScanFilter> filters;
    private BluetoothGatt mGatt;
    String mCurrentService;
    TextView tvBLE;
    ImageButton ibDownload;
    BluetoothDevice currDevice;
    private int id = 1000;
    public SensorDataAdapter adapter;
    final BLEActivity classe = this;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_ble);
        mHandler = new Handler();

        //mSensors = db.getAllSensorTypes();
        //BLUETOOTH LOW ENERGY NON SUPPORTATO
        if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
            Toast.makeText(this, "BLE Not Supported",
                    Toast.LENGTH_SHORT).show();
            finish();
        }
        final BluetoothManager bluetoothManager =
                (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
        mBluetoothAdapter = bluetoothManager.getAdapter();
        //VERIFICO SE IL BLUETOOTH DEL DISPOSITIVO E' ABILITATO
        //OPPURE NO. SE NON è ABILITATO DEVO CHIEDERE ALL'UTENTE DI ATTIVARLO
        // Ensures Bluetooth is available on the device and it is enabled. If not,
        if (mBluetoothAdapter == null || !mBluetoothAdapter.isEnabled()) {
            Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
        }

        ibDownload.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(currDevice!=null){
                    mGatt = currDevice.connectGatt(getBaseContext(), false, gattCallback);
                    scanLeDevice(false);// will stop after first device detection
                }
            }
        });
    }

    private void scanLeDevice(final boolean enable) {
        if (enable) {
            mHandler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    if (Build.VERSION.SDK_INT < 21) {
                        mBluetoothAdapter.stopLeScan(mLeScanCallback);
                    } else {
                        mLEScanner.stopScan(mScanCallback);

                    }
                }
            }, SCAN_PERIOD);
            if (Build.VERSION.SDK_INT < 21) {
                mBluetoothAdapter.startLeScan(mLeScanCallback);
            } else {
                mLEScanner.startScan(filters, settings, mScanCallback);
            }
        } else {
            if (Build.VERSION.SDK_INT < 21) {
                mBluetoothAdapter.stopLeScan(mLeScanCallback);
            } else {
                mLEScanner.stopScan(mScanCallback);
            }
        }
    }


    private ScanCallback mScanCallback = new ScanCallback() {
        @Override
        public void onScanResult(int callbackType, ScanResult result) {
            Log.i("callbackType", String.valueOf(callbackType));
            Log.i("result", result.toString());
            BluetoothDevice btDevice = result.getDevice();
            connectToDevice(btDevice);
        }

        @Override
        public void onBatchScanResults(List<ScanResult> results) {
            for (ScanResult sr : results) {
                Log.i("ScanResult - Results", sr.toString());
            }
        }

        @Override
        public void onScanFailed(int errorCode) {
            Log.e("Scan Failed", "Error Code: " + errorCode);
        }
    };

    private BluetoothAdapter.LeScanCallback mLeScanCallback =
            new BluetoothAdapter.LeScanCallback() {
                @Override
                public void onLeScan(final BluetoothDevice device, int rssi,
                                     byte[] scanRecord) {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Log.i("onLeScan", device.toString());
                            connectToDevice(device);
                        }
                    });
                }
            };

    public void connectToDevice(BluetoothDevice device) {
        if (mGatt == null) {
            currDevice = device;
            ibDownload.setEnabled(true);
            ibDownload.setImageResource(R.drawable.download_ok);
        }
    }

    private final BluetoothGattCallback gattCallback = new BluetoothGattCallback() {
        @Override
        public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
            Log.i("onConnectionStateChange", "Status: " + status);
            switch (newState) {
                case BluetoothProfile.STATE_CONNECTED:
                    Log.i("gattCallback", "STATE_CONNECTED");
                    gatt.discoverServices();
                    break;
                case BluetoothProfile.STATE_DISCONNECTED:
                    Log.e("gattCallback", "STATE_DISCONNECTED");
                    break;
                default:
                    Log.e("gattCallback", "STATE_OTHER");
            }
        }

     @Override
        public void onServicesDiscovered(BluetoothGatt gatt, int status) {
            List<BluetoothGattService> services = gatt.getServices();
            Log.i("onServicesDiscovered", services.toString());
            ;
            for(BluetoothGattService srv : services){
               // if(srv.getUuid().toString().equals(mSensors.get(1).getServUid())){
                    mCurrentService = srv.getUuid().toString();
                    //RECUPERO SOLO IL SERVIZIO CON UID 1130
                if(mCurrentService.contains("1130")){
                    List<BluetoothGattCharacteristic> mListCars = srv.getCharacteristics();
                    //leggo le caratteristiche del servizio che cerco
                    for(BluetoothGattCharacteristic bc : mListCars){
                        //recupero solo le caratteristiche 1131, 1132
                        if(bc.getUuid().toString().contains("1131") ||
                                bc.getUuid().toString().contains("1132")){
                            //LEGGO LE 2 CARATTERISTICHE NECESSARIE
                           gatt.readCharacteristic(srv.getCharacteristic(bc.getUuid()));
                        }

                    }
                }else{
                    Log.i("SERVIZIO NON CORRETTO", "SERVIZIO NON CORRETTO");
                }

              //  }
            }


        }

        @Override
        public void onCharacteristicRead(BluetoothGatt gatt,
                                         BluetoothGattCharacteristic
                                                 characteristic, int status) {
            Log.i("onCharacteristicRead", characteristic.toString());

               SensorData mSenData = new SensorData();
                    mSenData.setValue(characteristic.getStringValue(0));
                    Log.i("LETTURA DATI ", mSenData.getValue());
                    mSenData.setIdType(++id);
                    mSenData.setCharacteristic(characteristic.getUuid().toString());
                    mSenData.setValueTimestamp(db.getDateTime());
                    db.insertSensorData(mSenData);


        }




    };
}

使用此代码，我可以读取我的服务的第一个特征，并且只读取第一个特征的一个值。

我想自动读取BLE设备的所有特性值。如何更改我的代码才能执行此操作？

Answer 1

您可以使用以下代码实现多次读取：首先创建一个List

test.sh    #it means that ls command executed
test.sh: line 2: add: command not found  #it means that add function can't be called from  /etc/vim/vimrc or .bashrc  or .vimrc.

[4]+  Stopped                 vim test.sh

在private int ReadQueueIndex; private List<BluetoothGattCharacteristic> ReadQueue;中添加ReadQueue中的特征：

onServicesDiscovered

创建ReadQueue = new ArrayList<>(); ReadQueue.add(characteristicsList.get(2)); ReadQueue.add(characteristicsList.get(1)); ReadQueue.add(characteristicsList.get(0)); ReadQueueIndex = 2; ReadCharacteristics(ReadQueueIndex);方法

ReadCharacteristics

然后在private void ReadCharacteristics(int index){ bluetoothGatt.readCharacteristic(ReadQueue.get(index)); }回调中：

onCharacteristicRead

希望它有所帮助。

Answer 2

首先存储您的读取特征和ghatt对象。如果你想从特征中读取一个值，请调用此方法：

private fun readDataFromCharacteristic(ghatt: BluetoothGhatt? , characteristic:BluetoothGhattCharacteristic) {
        Log.d(TAG, " readDataFromCharacteristic")
        ghatt?.readCharacteristic(characteristic)
    }

如果你在ghatt上调用readCharacteristic（特征），下面的方法将给出结果

override fun onCharacteristicRead(gatt: BluetoothGatt, characteristic: BluetoothGattCharacteristic, status: Int) {}

Answer 3

你不应该在onServicesDiscovered方法中阅读完整的特征列表，因为ble设备可能没时间执行来自android客户端的所有请求。

我告诉你：

保留onServicesDiscovered的所有特征
轮流尝试在onCharacteristicRead方法中读取特征（首先读取第一个特征，在读取特征后，尝试读取第二个特征和...）

如何读取我的BLE设备的所有特性值？

3 个答案: