我正在尝试从德州传感器标签接收数据，但到目前为止，我只是设法连接并向其写入特征。
这是我的setCharacteristicNotification（）; 下面评论的部分不起作用，我没有设法使用它。
public void setCharacteristicNotification(BluetoothGattCharacteristic characteristic,
boolean enabled) {
if(bluetoothAdapter == null || bluetoothGatt == null) return;
bluetoothGatt.setCharacteristicNotification(characteristic, enabled);
if(GattUUIDs.containsUuid(characteristic.getUuid())) {
// BluetoothGattDescriptor descriptor = characteristic.getDescriptor(
// UUID.fromString(GattAttributes.CLIENT_CHARACTERISTIC_CONFIG));
BluetoothGattDescriptor descriptor = new BluetoothGattDescriptor(
GattUUIDs.UUID_CLIENT_CHAR_CONFIG, BluetoothGattDescriptor.PERMISSION_WRITE |
BluetoothGattDescriptor.PERMISSION_READ);
descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
bluetoothGatt.writeDescriptor(descriptor);
}
}
当我尝试调用注释块时，这就是我收到的内容：
java.lang.NullPointerException：尝试调用虚方法 'boolean android.bluetooth.BluetoothGattDescriptor.setValue（byte []）' 在空对象引用上
这是我的客户端特性配置UUID：
public static final UUID UUID_CLIENT_CHAR_CONFIG =
UUID.fromString(GattAttributes.CLIENT_CHARACTERISTIC_CONFIG);
public static String CLIENT_CHARACTERISTIC_CONFIG = "f0002902-0451-4000-b000-000000000000";
我认为它在我的描述符中存在某种问题，因为我可以注册它，但我从来没有得到它的回调。
如果有帮助，这是我的服务：
import android.app.Service;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattDescriptor;
import android.bluetooth.BluetoothGattService;
import android.bluetooth.BluetoothManager;
import android.bluetooth.BluetoothProfile;
import android.content.Context;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
import java.util.List;
import java.util.UUID;
/**
* Created by alan on 2/23/16.
*/
public class DeviceService extends Service {
private final static String TAG = DeviceService.class.getSimpleName();
private BluetoothGatt bluetoothGatt;
private String deviceAddress;
private BluetoothManager bluetoothManager;
private BluetoothAdapter bluetoothAdapter;
private int connectionState = STATE_DISCONNECTED;
public final IBinder binder = new LocalBinder();
public static final int STATE_DISCONNECTED = 0;
public static final int STATE_CONNECTING = 1;
public static final int STATE_CONNECTED = 2;
public static final String ACTION_GATT_SERVICES_DISCOVERED = "action_gatt_services_discovered";
public static final String ACTION_GATT_DISCONNECTED = "action_gatt_disconnected";
public static final String ACTION_GATT_CONNECTED = "action_gatt_connected";
public static final String ACTION_DATA_AVAILABLE = "action_data_available";
public static final String ACTION_DATA_NOTIFY = "action_data_notify";
public static final String ACTION_DATA_WRITE = "action_data_write";
public static final String ACTION_DATA_READ = "action_data_read";
public static final String EXTRA_DATA = "extra_data";
@Override
public IBinder onBind(Intent intent) {
return binder;
}
@Override
public boolean onUnbind(Intent intent) {
close();
return super.onUnbind(intent);
}
public boolean initialize() {
if(bluetoothManager == null) {
bluetoothManager = (BluetoothManager)getSystemService(Context.BLUETOOTH_SERVICE);
if(bluetoothManager == null) {
Log.e(TAG,"CANNOT INITIALIZE BLUETOOTH");
return false;
}
}bluetoothAdapter = bluetoothManager.getAdapter();
if(bluetoothAdapter == null) {
Log.e(TAG,"CANNOT FIND AN ADAPTER");
return false;
}return true;
}
public boolean connect(final String address) {
Log.w(TAG,"CONNECT PROCESS INITIALIZED");
if(bluetoothAdapter == null || address == null) {
Log.e(TAG,"ADAPTER NOT INITIALIZED");
return false;
}
//previously connected device, attempt to reconnect
if(deviceAddress != null && deviceAddress.equals(address)
&&bluetoothGatt != null) {
Log.d(TAG, "TRYING TO USE EXISTING GATT");
if(bluetoothGatt.connect()) {
connectionState = STATE_CONNECTING;
bluetoothGatt.connect();
return true;
} else
return false;
}
final BluetoothDevice device = bluetoothAdapter.getRemoteDevice(address);
if(device == null) {
Log.e(TAG, "DEVICE NOT FOUND");
return false;
}
bluetoothGatt = device.connectGatt(this, false, gattCallback);
deviceAddress = address;
connectionState = STATE_CONNECTING;
return true;
}
public void disconnect() {
if(bluetoothAdapter == null || bluetoothGatt == null) {
Log.w(TAG, "BLUETOOTH NOT INITIALIZED");
return;
}
bluetoothGatt.disconnect();
}
public void close() {
if(bluetoothGatt == null)
return;
bluetoothGatt.close();
bluetoothGatt = null;
}
public class LocalBinder extends Binder {
DeviceService getService() {
return DeviceService.this;
}
}
private final BluetoothGattCallback gattCallback = new BluetoothGattCallback() {
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
String intentAction;
if(newState == BluetoothProfile.STATE_CONNECTED) {
intentAction = ACTION_GATT_CONNECTED;
connectionState = STATE_CONNECTED;
broadcastUpdate(intentAction);
Log.i(TAG,"CONNECTED TO GATT SERVER!");
bluetoothGatt.discoverServices();
} else if(newState == BluetoothProfile.STATE_DISCONNECTED) {
intentAction = ACTION_GATT_DISCONNECTED;
connectionState = STATE_DISCONNECTED;
Log.i(TAG,"DISCONNECTED FROM GATT SERVER");
broadcastUpdate(intentAction);
}
}
@Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
Log.e(TAG,"STATUS: " + String.valueOf(status));
if (status == BluetoothGatt.GATT_SUCCESS)
broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);
}
@Override
public void onCharacteristicRead(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic,
int status) {
if (status == BluetoothGatt.GATT_SUCCESS)
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
@Override
public void onCharacteristicChanged(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic) {
Log.e(TAG,"CHAR CHANGED \n" + gatt.toString() + "\n" + characteristic.getUuid().toString() + "\n");
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
@Override
public void onCharacteristicWrite(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic,
int status) {
Log.e(TAG,"CHAR WROTE" + gatt.toString() + "\n" + characteristic.getUuid().toString() + "\n");
if(status == BluetoothGatt.GATT_SUCCESS)
broadcastUpdate(ACTION_DATA_WRITE, characteristic);
}
};
public void readCharacteristic(BluetoothGattCharacteristic characteristic) {
if(bluetoothAdapter == null || bluetoothGatt == null) {
Log.e(TAG, "ADAPTER NOT INITIALIZED");
return;
}
bluetoothGatt.readCharacteristic(characteristic);
}
public void writeCharacteristic(BluetoothGattCharacteristic characteristic, byte[] value) {
if(bluetoothAdapter == null || bluetoothGatt == null) {
Log.e(TAG, "ADAPTER NOT INITIALIZED");
return;
}
characteristic.setValue(value);
characteristic.setWriteType(BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE);
bluetoothGatt.writeCharacteristic(characteristic);
System.out.println("Write value: " + value[0] + " on UUID: " + characteristic.getUuid().toString());
}
public void setCharacteristicNotification(BluetoothGattCharacteristic characteristic,
boolean enabled) {
if(bluetoothAdapter == null || bluetoothGatt == null) return;
bluetoothGatt.setCharacteristicNotification(characteristic, enabled);
if(GattUUIDs.containsUuid(characteristic.getUuid())) {
BluetoothGattDescriptor descriptor = characteristic.getDescriptor(
UUID.fromString(GattAttributes.CLIENT_CHARACTERISTIC_CONFIG));
// BluetoothGattDescriptor descriptor = new BluetoothGattDescriptor(
// GattUUIDs.UUID_CLIENT_CHAR_CONFIG, BluetoothGattDescriptor.PERMISSION_WRITE |
// BluetoothGattDescriptor.PERMISSION_READ);
descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
bluetoothGatt.writeDescriptor(descriptor);
}
}
public void setCharacteristicIndication(BluetoothGattCharacteristic characteristic,
boolean enabled) {
if(bluetoothAdapter ==null || bluetoothGatt == null) return;
BluetoothGattDescriptor descriptor = characteristic.getDescriptor(
UUID.fromString(GattAttributes.CLIENT_CHARACTERISTIC_CONFIG));
descriptor.setValue(BluetoothGattDescriptor.ENABLE_INDICATION_VALUE);
bluetoothGatt.writeDescriptor(descriptor);
bluetoothGatt.setCharacteristicNotification(characteristic, enabled);
}
private void broadcastUpdate(final String action) {
final Intent intent = new Intent(action);
sendBroadcast(intent);
}
private void broadcastUpdate(final String action,
final BluetoothGattCharacteristic characteristic) {
final Intent intent = new Intent(action);
final UUID uuid = characteristic.getUuid();
Log.w(TAG,"BROADCAST UPDATE WITH ACTION: " + action);
if(GattUUIDs.containsUuid(uuid)) {
Log.e(TAG,"PASSOU AQUI");
int flag = characteristic.getProperties();
int format;
if((flag & 0x01) != 0)
format = BluetoothGattCharacteristic.FORMAT_UINT16;
else
format = BluetoothGattCharacteristic.FORMAT_UINT8;
byte[] data = characteristic.getValue();
if (GattUUIDs.UUID_IR_TEMPERATURE_MEASUREMENT.equals(uuid)) {
float objectTemperature = ((((float)data[1] * 256 + (float)data[0]) / (float)4)) * (float)0.03125;
float ambientTemperature = ((((float)data[3] * 256 + (float)data[2]) / (float)4)) * (float)0.03125;
// final int temp_data = characteristic.getIntValue(format, 1);
intent.putExtra(EXTRA_DATA, String.format("%.2f %.2f", objectTemperature, ambientTemperature));
} else if (GattUUIDs.UUID_IR_TEMPERATURE_CONFIG.equals(uuid)) {
if (data[0] == 0)
intent.putExtra(EXTRA_DATA, "IR DISABLED");
else
intent.putExtra(EXTRA_DATA, "IR ENABLED");
} else if (GattUUIDs.UUID_IR_TEMPERATURE_PERIOD.equals(uuid))
intent.putExtra(EXTRA_DATA, String.format("%d",data[0]*10));
else if (GattUUIDs.UUID_OPTICAL_MEASUREMENT.equals(uuid)) {
int m = (data[1] * 256 + data[0]) & 0x0FFF;
int e = ((data[1] * 256 + data[0]) & 0xF000) >> 12;
double lux = m * 0.01 * Math.pow(2.0,e);
intent.putExtra(EXTRA_DATA, String.format("%.2f",lux));
} else if (GattUUIDs.UUID_OPTICAL_CONFIG.equals(uuid)) {
if(data[0] == 0)
intent.putExtra(EXTRA_DATA, "OPTICAL DISABLED");
else
intent.putExtra(EXTRA_DATA, "OPTICAL ENABLED");
} else if (GattUUIDs.UUID_OPTICAL_PERIOD.equals(uuid))
intent.putExtra(EXTRA_DATA, String.format("%d",data[0] * 10));
else if (GattUUIDs.UUID_MOVEMENT_MEASUREMENT.equals(uuid))
intent.putExtra(EXTRA_DATA, String.format("%d %d %d %d %d %d %d %d %d",
(data[0] + data[1]*256),
(data[2] + data[3]*256),
(data[4] + data[5]*256),
(data[6] + data[7]*256),
(data[8] + data[9]*256),
(data[10] + data[11]*256),
(data[12] + data[13]*256),
(data[14] + data[15]*256),
(data[16] + data[17]*256)));
else if (GattUUIDs.UUID_MOVEMENT_CONFIG.equals(uuid)) {
if (data[0] == 0)
intent.putExtra(EXTRA_DATA, "MOVEMENT DISABLED");
else
intent.putExtra(EXTRA_DATA, "MOVEMENT ENABLEd");
} else if (GattUUIDs.UUID_MOVEMENT_PERIOD.equals(uuid))
intent.putExtra(EXTRA_DATA, String.format("%d",data[0] * 10));
else {
if (data != null && data.length > 0) {
final StringBuilder stringBuilder = new StringBuilder(data.length);
for(byte byteChar : data)
stringBuilder.append(String.format("%02X ",byteChar));
intent.putExtra(EXTRA_DATA, new String(data) + "\n" + stringBuilder.toString());
}
}
}
sendBroadcast(intent);
}
public List<BluetoothGattService> getSupportedGattServices() {
if(bluetoothGatt == null) return null;
return bluetoothGatt.getServices();
}
}
这是我的设备控制：
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattService;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.CompoundButton;
import android.widget.Switch;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.UUID;
/**
* Created by alan on 2/23/16.
*/
public class DeviceControl extends AppCompatActivity {
private final String TAG = DeviceControl.class.getSimpleName();
private ArrayList<ArrayList<BluetoothGattCharacteristic>> mGattCharacterics = new ArrayList<>();
private BluetoothGattCharacteristic bluetoothGattCharacteristic;
public static String ADDRESS;
private DeviceService deviceService;
private boolean connected = false;
private TextView dataText;
private Switch temperatureSwitch,
movementSwitch,
opticalSwitch;
private final String LIST_NAME = "NAME";
private final String LIST_UUID = "UUID";
private final ServiceConnection serviceConnection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Log.e(TAG,"ONSERVICECONNECTED");
deviceService = ((DeviceService.LocalBinder)service).getService();
if(!deviceService.initialize())
finish();
deviceService.connect(ADDRESS);
}
@Override
public void onServiceDisconnected(ComponentName name) {
deviceService = null;
}
};
@Override
public void onCreate(Bundle savedInstanceBundle) {
super.onCreate(savedInstanceBundle);
setContentView(R.layout.activity_device_control);
dataText = (TextView)findViewById(R.id.dataText);
temperatureSwitch = (Switch)findViewById(R.id.temperatureSwitch);
movementSwitch = (Switch)findViewById(R.id.movementSwitch);
opticalSwitch = (Switch)findViewById(R.id.opticalSwitch);
temperatureSwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if(isChecked && connected)
writeCharacteristic(GattUUIDs.UUID_IR_TEMPERATURE_CONFIG, true);
else if(!isChecked && connected)
writeCharacteristic(GattUUIDs.UUID_IR_TEMPERATURE_CONFIG, false);
}
});
Bundle extras = getIntent().getExtras();
if(extras != null) {
setTitle(extras.getString("title"));
ADDRESS = extras.getString("address");
Intent intent = new Intent(this, DeviceService.class);
bindService(intent, serviceConnection, BIND_AUTO_CREATE);
}
registerReceiver(broadcastReceiver, makeIntentFilter());
}
public void writeCharacteristic(UUID toFind, boolean read) {
BluetoothGattCharacteristic gattCharacteristic = null;
byte[] enable = {(byte)0x01},
disable = {(byte)0x00};
for(int i = 0; i < mGattCharacterics.size(); i++) {
for(int j = 0; j < mGattCharacterics.get(i).size(); j++) {
if(mGattCharacterics.get(i).get(j).getUuid().equals(toFind))
gattCharacteristic = mGattCharacterics.get(i).get(j);
}
}
if(gattCharacteristic != null) {
if(read)
deviceService.writeCharacteristic(gattCharacteristic, enable);
else
deviceService.writeCharacteristic(gattCharacteristic, disable);
deviceService.setCharacteristicNotification(gattCharacteristic, true);
} else
Log.e(TAG,"NOTHING FOUND");
}
@Override
protected void onResume() {
super.onResume();
registerReceiver(broadcastReceiver, makeIntentFilter());
Log.w(TAG,"REGISTER RECEIVER");
if (deviceService != null) {
final boolean result = deviceService.connect(ADDRESS);
Log.d(TAG,"CONNECT RESULT = " + result);
}
}
@Override
protected void onPause() {
super.onPause();
unregisterReceiver(broadcastReceiver);
}
@Override
public void onBackPressed() {
super.onBackPressed();
deviceService.disconnect();
}
@Override
protected void onDestroy() {
super.onDestroy();
unbindService(serviceConnection);
deviceService = null;
}
private final BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
Log.e(TAG,"BROADCAST ACTION"+action);
switch (action) {
case DeviceService.ACTION_GATT_CONNECTED:
connected = true;
break;
case DeviceService.ACTION_GATT_DISCONNECTED:
connected = false;
break;
case DeviceService.ACTION_GATT_SERVICES_DISCOVERED:
getGattServices(deviceService.getSupportedGattServices());
break;
case DeviceService.ACTION_DATA_AVAILABLE:
displayData(intent.getStringExtra(DeviceService.EXTRA_DATA));
}
}
};
private void displayData(String data) {
if(data != null)
dataText.setText(data);
}
private void getGattServices(List<BluetoothGattService> gattServices) {
if(gattServices == null) return;
String uuid = null;
ArrayList<HashMap<String, String>> gattServiceData = new ArrayList<>();
ArrayList<ArrayList<HashMap<String, String>>> gattCharacteristicData
= new ArrayList<>();
mGattCharacterics = new ArrayList<>();
for (BluetoothGattService gattService : gattServices) {
HashMap<String, String> currentServiceData = new HashMap<>();
uuid = gattService.getUuid().toString();
currentServiceData.put(LIST_NAME, GattAttributes.lookup(uuid, "UnknownService"));
currentServiceData.put(LIST_UUID, uuid);
gattServiceData.add(currentServiceData);
ArrayList<HashMap<String, String>> gattCharacteristicGroupData = new ArrayList<>();
List<BluetoothGattCharacteristic> gattCharacteristics = gattService.getCharacteristics();
ArrayList<BluetoothGattCharacteristic> charas = new ArrayList<>();
for(BluetoothGattCharacteristic gattCharacteristic : gattCharacteristics) {
charas.add(gattCharacteristic);
HashMap<String, String> currentCharaData = new HashMap<>();
uuid = gattCharacteristic.getUuid().toString();
currentCharaData.put(LIST_NAME, GattAttributes.lookup(uuid, "UnknownCharacteristic"));
currentCharaData.put(LIST_UUID, uuid);
gattCharacteristicGroupData.add(currentCharaData);
//System.out.println("GATTCHAR\n\n" + gattCharacteristic.toString()+"\n");
}
mGattCharacterics.add(charas);
gattCharacteristicData.add(gattCharacteristicGroupData);
}
}
private static IntentFilter makeIntentFilter() {
final IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(DeviceService.ACTION_GATT_CONNECTED);
intentFilter.addAction(DeviceService.ACTION_GATT_DISCONNECTED);
intentFilter.addAction(DeviceService.ACTION_GATT_SERVICES_DISCOVERED);
intentFilter.addAction(DeviceService.ACTION_DATA_AVAILABLE);
return intentFilter;
}
}
感谢您的关注。