我正在开发一个应用程序与BLE设备连接，我下面的谷歌开发者指南。
按照开发人员指南我已经扫描BLE装置，并成功地与他们建立连接，并能够获得可用的服务和特性。
在这里我的问题是当我试图读取使用特征值
bluetoothGatt.readCharacteristic(gattCharacteristic)
但它不工作他并没有叫关贸总协定回调方法
onCharacteristicRead
这些特征属性是因为，我没有使用描述或支持任何通知阅读。
我尝试在SO和谷歌中提到的所有解决方案，但我还是很无力解决这一问题
我是新来这个概念，如果任何人能帮助我。
请找到下面的参考代码：
这个类是bluetoothgatt回调的服务。
private BluetoothGattCallback bluetoothGattCallback = new BluetoothGattCallback() {
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
String intentAction;
bluetoothGatt = gatt;
if (newState == BluetoothProfile.STATE_CONNECTED) {
//bluetoothGatt = gatt;
intentAction = Constants.GATT_CONNECTED;
Log.i(TAG, "Connected to GATT server.");
// Attempts to discover services after successful connection.
Log.i(TAG, "Attempting to start service discovery:" +
bluetoothGatt.discoverServices());
gatt.discoverServices();
broadCastUpdates(intentAction);
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
intentAction = Constants.GATT_DISCONNECTED;
Log.i(TAG, "Disconnected to GATT server.");
broadCastUpdates(intentAction);
}
super.onConnectionStateChange(gatt, status, newState);
}
@Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadCastUpdates(Constants.GATT_SERVICE_DISCOVERED);
Log.i("Services count", " " + gatt.getServices().size());
} else {
Log.w(TAG, "onServicesDiscovered received: " + status);
}
super.onServicesDiscovered(gatt, status);
}
@Override
public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
Log.e(TAG, "Characteristics calling");
UUID charUuid = characteristic.getUuid();
Intent intent = new Intent(Constants.GATT_DATA_AVAILABLE);
Bundle bundle = new Bundle();
// Putting the byte value read for GATT Db
bundle.putByteArray(Constants.EXTRA_BYTE_VALUE,
characteristic.getValue());
bundle.putString(Constants.EXTRA_BYTE_UUID_VALUE,
characteristic.getUuid().toString());
if (charUuid
.equals(UUID_MANUFATURE_NAME_STRING)) {
bundle.putString(Constants.EXTRA_MNS_VALUE,
Constants.getDisplayString(characteristic));
}
// Model number read value
else if (charUuid.equals(UUID_MODEL_NUMBER_STRING)) {
bundle.putString(Constants.EXTRA_MONS_VALUE,
Constants.getDisplayString(characteristic));
}
// Serial number read value
else if (charUuid
.equals(UUID_SERIAL_NUMBER_STRING)) {
bundle.putString(Constants.EXTRA_SNS_VALUE,
Constants.getDisplayString(characteristic));
}
// Hardware revision read value
else if (charUuid
.equals(UUID_HARDWARE_REVISION_STRING)) {
bundle.putString(Constants.EXTRA_HRS_VALUE,
Constants.getDisplayString(characteristic));
}
// Firmware revision read value
else if (charUuid
.equals(UUID_FIRWARE_REVISION_STRING)) {
bundle.putString(Constants.EXTRA_FRS_VALUE,
Constants.getDisplayString(characteristic));
}
// Software revision read value
else if (charUuid
.equals(UUID_SOFTWARE_REVISION_STRING)) {
bundle.putString(Constants.EXTRA_SRS_VALUE,
Constants.getDisplayString(characteristic));
}
// PNP ID read value
else if (charUuid.equals(UUID_PNP_ID)) {
bundle.putString(Constants.EXTRA_PNP_VALUE,
Constants.getDisplayString(characteristic));
}
// System ID read value
else if (charUuid.equals(UUID_SYSTEM_ID)) {
bundle.putString(Constants.EXTRA_SID_VALUE,
Constants.getDisplayString(characteristic));
}
intent.putExtras(bundle);
sendBroadcast(intent);
}
Log.e(TAG, "Characterstics calling");
//broadCastUpdates(Constants.GATT_DATA_AVAILABLE, characteristic);
//super.onCharacteristicRead(gatt, characteristic, status);
}
@Override
public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
Log.e(TAG, "Characteristic write calling");
super.onCharacteristicWrite(gatt, characteristic, status);
}
@Override
public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
Log.e(TAG, "Characteristic change calling");
super.onCharacteristicChanged(gatt, characteristic);
}
@Override
public void onDescriptorRead(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) {
Log.e(TAG, "Descriptor calling");
super.onDescriptorRead(gatt, descriptor, status);
}
@Override
public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) {
Log.e(TAG, "Descriptor write calling");
super.onDescriptorWrite(gatt, descriptor, status);
}
@Override
public void onReliableWriteCompleted(BluetoothGatt gatt, int status) {
super.onReliableWriteCompleted(gatt, status);
}
@Override
public void onReadRemoteRssi(BluetoothGatt gatt, int rssi, int status) {
super.onReadRemoteRssi(gatt, rssi, status);
}
};
/* public static void setNotifyCharacteristics(BluetoothGattCharacteristic notifyCharacteristics) {
bluetoothGatt.setCharacteristicNotification(notifyCharacteristics, true);
BluetoothGattDescriptor gattDescriptor = notifyCharacteristics.getDescriptor(notifyCharacteristics.getDescriptors().get(0).getUuid());
gattDescriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
bluetoothGatt.writeDescriptor(gattDescriptor);
}*/
public void readCharacteristics(BluetoothGattCharacteristic gattCharacteristic) {
if (bluetoothGatt != null) {
int charaProp = gattCharacteristic.getProperties();
Log.e(TAG, "Property-" + charaProp);
Log.e(TAG, gattCharacteristic.getUuid().toString());
bluetoothGatt.discoverServices();
bluetoothGatt.readCharacteristic(gattCharacteristic);
Log.e(TAG, "Gatt is not null");
} else {
Log.e(TAG, "Gatt is null");
}
}
下面类就是我打电话readCharacteristic
private BroadcastReceiver characteristicReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
Bundle extras = intent.getExtras();
if (Constants.GATT_DATA_AVAILABLE.equals(action)) {
if (extras != null) {
String name = extras.getString(Constants.EXTRA_MNS_VALUE);
Log.e("This is test name :-", name);
byte[] valueArry = extras.getByteArray(Constants.EXTRA_BYTE_VALUE);
displayHexValue(valueArry);
displayName(tvTempType.getText().toString());
}
} else {
Toast.makeText(context, "There is no extra data.", Toast.LENGTH_SHORT).show();
}
}
};
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_character_details);
try {
tvUid = findViewById(R.id.tvCharUid);
tvTemprature = findViewById(R.id.tvTemprature);
tvCharName = findViewById(R.id.tvCharName);
tvTempType = findViewById(R.id.tvTypename);
ArrayList<BluetoothGattCharacteristic> bluetoothGattCharacteristics = getIntent().getParcelableArrayListExtra(Constants.CHARACTERISTIC);
int selectPos = getIntent().getIntExtra(Constants.SELECTED_SERVICE, 0);
gattCharacteristic = bluetoothGattCharacteristics.get(selectPos);
registerReceiver(characteristicReceiver, Constants.makeGattUpdateIntentFilter());
BLEGattService bleGattService = new BLEGattService();
bleGattService.readCharacteristics(gattCharacteristic);
String uid = gattCharacteristic.getUuid().toString();
String displayUid = Constants.getDisplayString(gattCharacteristic);
tvUid.setText(displayUid);
} catch (Exception e) {
e.printStackTrace();
}
/*String name = Constants.getDisplayString(gattCharacteristic);
tvCharName.setText(name);*/
}
@Override
protected void onResume() {
super.onResume();
registerReceiver(characteristicReceiver, Constants.makeGattUpdateIntentFilter());
}
@Override
protected void onDestroy() {
super.onDestroy();
unregisterReceiver(characteristicReceiver);
}
尝试使用自己定制的方法对每个特征。你需要知道你的服务，你的特点的UUID的UUID：
public void readCustomCharacteristic() {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
/*check if the service is available on the device*/
BluetoothGattService mCustomService = mBluetoothGatt.getService(UUID.fromString("UUID of service"));
if(mCustomService == null){
Log.w(TAG, "Custom BLE Service not found");
return;
}
/*get the read characteristic from the service*/
BluetoothGattCharacteristic mReadCharacteristic = mCustomService.getCharacteristic(UUID.fromString("UUID of characteristic"));
if(mBluetoothGatt.readCharacteristic(mReadCharacteristic) == false){
Log.w(TAG, "Failed to read characteristic");
}
}
public void writeCustomCharacteristic(byte[] value) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
/*check if the service is available on the device*/
BluetoothGattService mCustomService = mBluetoothGatt.getService(UUID.fromString("UUID of service"));
if(mCustomService == null){
Log.w(TAG, "Custom BLE Service not found");
return;
}
/*get the read characteristic from the service*/
BluetoothGattCharacteristic mWriteCharacteristic = mCustomService.getCharacteristic(UUID.fromString("UUID of characteristic"));
mWriteCharacteristic.setValue(value);
if(mBluetoothGatt.writeCharacteristic(mWriteCharacteristic) == false){
Log.w(TAG, "Failed to write characteristic");
}
}