很抱歉提出一个老问题，但这是我在使用蓝牙 (BLE) 4.0 时遇到的许多问题的解决方案。再次为下面的大类感到抱歉，但请确保它们是必需的，并且没有不相关或未使用的方法。
public abstract class AbstractBluetoothBroadcaster extends BroadcastReceiver {
protected static final String LOG_TAG = BluetoothLowEnergy.LOG_TAG;
protected BluetoothLowEnergy bluetoothLowEnergy;
public AbstractBluetoothBroadcaster(BluetoothLowEnergy bluetoothLowEnergy, String action){
super();
this.bluetoothLowEnergy = bluetoothLowEnergy;
IntentFilter intentFilterStateChange = new IntentFilter(action);
intentFilterStateChange.setPriority(IntentFilter.SYSTEM_HIGH_PRIORITY);
this.bluetoothLowEnergy.getActivity().registerReceiver(this, intentFilterStateChange);
}
public void onDestroy(){
this.bluetoothLowEnergy.getActivity().unregisterReceiver(this);
}
}
public class BluetoothBondStateBroadcaster extends AbstractBluetoothBroadcaster {
private BluetoothLowEnergy bluetoothLowEnergy;
private boolean deviceBonded;
public BluetoothBondStateBroadcaster(BluetoothLowEnergy bluetoothLowEnergy) {
super(bluetoothLowEnergy, BluetoothDevice.ACTION_BOND_STATE_CHANGED);
this.bluetoothLowEnergy = bluetoothLowEnergy;
this.deviceBonded = false;
}
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (action == null){
return;
}
BluetoothDevice bluetoothDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
if (action.equals(BluetoothDevice.ACTION_BOND_STATE_CHANGED) &&
bluetoothDevice != null &&
bluetoothDevice.getAddress().equals(bluetoothLowEnergy.getDeviceUUID())) {
int state = intent.getIntExtra(BluetoothDevice.EXTRA_BOND_STATE, -1);
switch (state) {
case BluetoothDevice.BOND_NONE:
Log.d(LOG_TAG, " NOT BONDED - dev " + bluetoothDevice.getAddress());
this.deviceBonded = false;
break;
case BluetoothDevice.BOND_BONDING:
Log.d(LOG_TAG, " BONDING ... - dev " + bluetoothDevice.getAddress());
break;
case BluetoothDevice.BOND_BONDED:
Log.d(LOG_TAG, " BONDED - dev " + bluetoothDevice.getAddress());
deviceBonded = true;
bluetoothLowEnergy.onBluetoothBonded();
break;
default:
break;
}
}
}
public void resetDeviceBonded(){
this.deviceBonded = false;
}
public boolean isDeviceBonded() {
return deviceBonded;
}
}
public class BluetoothPairingBroadcaster extends AbstractBluetoothBroadcaster {
private String devicePIN;
public BluetoothPairingBroadcaster(BluetoothLowEnergy bluetoothLowEnergy){
super(bluetoothLowEnergy, BluetoothDevice.ACTION_PAIRING_REQUEST);
this.devicePIN = "";
}
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (action == null){
return;
}
BluetoothDevice bluetoothDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
int pairingType = intent.getIntExtra(BluetoothDevice.EXTRA_PAIRING_VARIANT, BluetoothDevice.ERROR);
if (action.equals(BluetoothDevice.ACTION_PAIRING_REQUEST) &&
bluetoothDevice != null &&
bluetoothDevice.getAddress().equals(bluetoothLowEnergy.getDeviceUUID()) &&
!getDevicePIN().isEmpty()) {
if (pairingType == BluetoothDevice.PAIRING_VARIANT_PIN){
bluetoothDevice.setPin(getDevicePIN().getBytes());
Log.d(LOG_TAG," Auto-entering pin - " + getDevicePIN());
bluetoothDevice.createBond();
Log.d(LOG_TAG," pin entered and request sent...");
abortBroadcast();
}
}
}
public void setDevicePIN(String pin){
this.devicePIN = pin;
}
public String getDevicePIN(){
return this.devicePIN ;
}
}
public class BluetoothLowEnergy extends BluetoothGattCallback {
// listener that has the methods that the application (activity)
// will use to send / receive data, or to reflect the system state
// in the UI
public interface BluetoothListener {
/**
* Triggered when the scanning has started successfully
*/
void onBluetoothStartScan();
/**
* Triggered when the scanning stops
* @param scanResults results of the scanning
*/
void onBluetoothStopScan(Collection<BluetoothDevice> scanResults);
/**
* Triggered when the device is ready to send/receive data
*/
void onBluetoothConnectionReady();
/**
* Triggered when a bluetooth msg is received
* @param msg message received
*/
void onBluetoothReceiveMsg(String msg);
/**
* Triggered whenever data is send
* @param success true means data was sent fine to the remote device, false otherwise
*/
void onBluetoothSend(String data, boolean success);
/**
* Triggered if no bluetooth is connected, and we need a connection
* to send / receive / discover services
*/
void onBluetoothNotConnected();
}
// custom exceptions
public class BluetoothNotEnabledException extends Exception { }
public class BluetoothLowEnergyNotSupported extends Exception { }
public class BluetoothDeviceNotFound extends Exception { }
// service and characteristic uuids that are going to be used to
// send / receive data between central and peripheral GATTs
private static final String SERVICE_UUID = "FFE0-";
private static final String CHARACTERISTIC_UUID = "FFE1-";
// timeout for bluetooth scan (in ms)
public static final int SCAN_TIMEOUT = 5000;
// BLE LOG TAG
public static final String LOG_TAG = "BLUETOOTH_BLE";
// model
private boolean bluetoothScanning;
private boolean bluetoothConnected;
private Map<String, BluetoothDevice> bluetoothScanResults;
// gui
private Activity activity;
// bluetooth
private BluetoothAdapter bluetoothAdapter;
private BluetoothLeScanner bluetoothLeScanner;
private ScanCallback bluetoothScanCallback;
private BluetoothGatt bluetoothGatt;
private BluetoothGattCharacteristic characteristic;
public BluetoothLowEnergy(Activity activity, BluetoothListener bluetoothListener){
this.activity = activity;
this.bluetoothListener = bluetoothListener;
// this keeps track of the scanning and connection states
this.bluetoothScanning = this.bluetoothConnected = false;
// keeps track of the scanning results
this.bluetoothScanResults = new HashMap<>();
// set bluetooth pairing request and bonded callback
// these broadcasters will be responsible to detect and validate
// the bonded state of your device
this.pairingRequestBroadcaster = new BluetoothPairingBroadcaster(this);
this.bondedBroadcaster = new BluetoothBondStateBroadcaster(this);
// set the scan callback methods that will add results to
// this.bluetoothScanResults map
this.bluetoothScanCallback = new ScanCallback() {
@Override
public void onScanResult(int callbackType, ScanResult result) {
super.onScanResult(callbackType, result);
addScanResult(result);
}
@Override
public void onBatchScanResults(List<ScanResult> results) {
super.onBatchScanResults(results);
for (ScanResult result: results) {
addScanResult(result);
}
}
@Override
public void onScanFailed(int errorCode) {
super.onScanFailed(errorCode);
Log.e(LOG_TAG, "Scan Failed with code " + errorCode);
}
private void addScanResult(ScanResult result) {
BluetoothDevice device = result.getDevice();
String deviceAddress = device.getAddress();
bluetoothScanResults.put(deviceAddress, device);
Log.d(LOG_TAG, "Found device " + deviceAddress);
}
};
// Use this to determine whether BLE is supported on the device.
if (!this.activity.getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
throw new BluetoothLowEnergyNotSupported();
}
}
/**
* This method should be called when the activity is destroyed
*/
public void onDestroy(){
this.bondedBroadcaster.onDestroy();
this.pairingRequestBroadcaster.onDestroy();
this.disconnect();
}
/**
* This method is called when we finish pairing/bonding to the device
*/
public void onBluetoothBonded(){
// if we have the services already discovered, then we can
// send/receive data, to do so we call the bluetooth listener below
if (servicesDiscovered){
this.bluetoothListener.onBluetoothConnectionReady();
// if we know we have a connection established, then we can
// discover services
} else if (bluetoothConnected){
bluetoothGatt.discoverServices();
}
}
/**
* This method is called whenever a connection is established or a disconnection happens
*/
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
super.onConnectionStateChange(gatt, status, newState);
BluetoothDevice bluetoothDevice = gatt.getDevice();
// if these conditions == true, then we have a disconnect
if ( status == BluetoothGatt.GATT_FAILURE ||
status != BluetoothGatt.GATT_SUCCESS ||
newState == BluetoothProfile.STATE_DISCONNECTED) {
Log.d(LOG_TAG, String.format(Locale.getDefault(),
"Disconnected from %s (%s) - status %d - state %d",
bluetoothDevice.getName(),
bluetoothDevice.getAddress(),
status,
newState
));
this.disconnect();
// if these conditions == true, then we have a successful connection
} else if (newState == BluetoothProfile.STATE_CONNECTED) {
bluetoothConnected = true;
Log.d(LOG_TAG, String.format(Locale.getDefault(),
"Connected to %s (%s) - status %d - state %d",
bluetoothDevice.getName(),
bluetoothDevice.getAddress(),
status,
newState
));
// this sleep is here to avoid TONS of problems in BLE, that occur whenever we start
// service discovery immediately after the connection is established
try {
Thread.sleep(600);
} catch (InterruptedException e) {
e.printStackTrace();
}
gatt.discoverServices();
}
}
@Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
super.onServicesDiscovered(gatt, status);
if (status != BluetoothGatt.GATT_SUCCESS) {
return;
}
// BEGIN - find the service and characteristic that we want (defined as a static attribute
// of the BluetoothLowEnergy class)
Log.d(LOG_TAG, "Discovering services ...");
BluetoothGattService service = null;
for (BluetoothGattService serv: gatt.getServices()){
Log.d(LOG_TAG, "Found service " + serv.getUuid().toString());
if (serv.getUuid().toString().toUpperCase().contains(SERVICE_UUID)){
service = serv;
Log.d(LOG_TAG, "---> Selected service " + serv.getUuid().toString());
break;
}
}
if (service == null){
return;
}
for (BluetoothGattCharacteristic charac: service.getCharacteristics()){
Log.d(LOG_TAG, "Found characteristic " + charac.getUuid().toString());
if (charac.getUuid().toString().toUpperCase().contains(CHARACTERISTIC_UUID)){
this.characteristic = charac;
Log.d(LOG_TAG, "---> Selected characteristic " + charac.getUuid().toString());
break;
}
}
if (this.characteristic == null){
return;
}
Log.d(LOG_TAG, "Setting write and notification to the characteristic ...");
bluetoothAdapter.cancelDiscovery();
// END - find the service and characteristic
// set that we want to write to the selected characteristic and be notified if
// it changes (the remote GATT peripheral sends data to the Android's GATT Center)
this.characteristic.setWriteType(BluetoothGattCharacteristic.WRITE_TYPE_DEFAULT);
gatt.setCharacteristicNotification(this.characteristic, true);
// we finished service discovery
this.servicesDiscovered = true;
// if we have paired/bonded then we are ready to send/receive data
if (pairingRequestBroadcaster.getDevicePIN().isEmpty() || bondedBroadcaster.isDeviceBonded()) {
this.bluetoothListener.onBluetoothConnectionReady();
}
}
@Override
public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic charac, int status) {
super.onCharacteristicRead(gatt, charac, status);
restartDisconnectTimeout();
if (status != BluetoothGatt.GATT_SUCCESS) {
return;
}
try {
String characValue = new String(charac.getValue(), CHARSET)
.replaceAll(DATA_FILTER_REGEX,"");
Log.i(LOG_TAG, String.format(Locale.getDefault(),
"Characteristic Read - %s",
characValue
));
if (charac.getUuid().equals(this.characteristic.getUuid())) {
this.bluetoothListener.onBluetoothReceiveMsg(characValue);
}
} catch (UnsupportedEncodingException e) {
Log.e(LOG_TAG, "Characteristic Read - Failed to convert message string to byte array");
}
}
@Override
public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic charac, int status) {
super.onCharacteristicWrite(gatt, charac, status);
restartDisconnectTimeout();
try {
String characValue = new String(charac.getValue(), CHARSET);
Log.i(LOG_TAG, String.format(Locale.getDefault(),
"Characteristic Write - SUCCESS - %s",
characValue
));
bluetoothListener.onBluetoothSend( characValue, (status == BluetoothGatt.GATT_SUCCESS) );
} catch (UnsupportedEncodingException e) {
Log.e(LOG_TAG, "Characteristic Write - Failed to convert message string to byte array");
}
}
@Override
public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic charac) {
super.onCharacteristicChanged(gatt, charac);
Log.d(LOG_TAG,"Characteristic Changed");
onCharacteristicRead(gatt, charac, BluetoothGatt.GATT_SUCCESS);
}
/**
* Remove pairing/bonding of the device
* @param device Device to remove bonding
*/
public static void removeBond(BluetoothDevice device){
try {
if (device == null){
throw new Exception();
}
Method method = device.getClass().getMethod("removeBond", (Class[]) null);
method.invoke(device, (Object[]) null);
Log.d(LOG_TAG, "removeBond() called");
Thread.sleep(600);
Log.d(LOG_TAG, "removeBond() - finished method");
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Clears the GATT services cache, so that new services can be discovered
* @param bluetoothGatt GATT Client to clear service's discovery cache
*/
public static void refresh(BluetoothGatt bluetoothGatt){
try {
Method method = bluetoothGatt.getClass().getMethod("refresh", (Class[]) null);
method.invoke(bluetoothGatt, (Object[]) null);
} catch (Exception e){
e.printStackTrace();
}
}
/**
* Connect to the GATT Peripheral device
* @param uuid GATT Peripheral address / mac / uuid to connect to
* @param pin PIN to authenticate and pair to the device
*/
public void connect(String uuid, String pin) throws BluetoothNotEnabledException, BluetoothDeviceNotFound {
checkBluetooth();
// do not connect twice
if (this.isConnected()){
return;
}
// get device
BluetoothDevice device = this.bluetoothScanResults.get(uuid);
if (device == null){
throw new BluetoothDeviceNotFound();
}
this.deviceUUID = uuid;
pairingRequestBroadcaster.setDevicePIN(pin);
removeBond(device);
// create connection to the bluetooth device
bluetoothGatt = device.connectGatt(activity, false, this);
refresh(bluetoothGatt);
}
/**
* Disconnect from BLE device. This method should be called whenever we want to
* close the APP, or the BLE connection.
*/
public void disconnect() {
Log.d(LOG_TAG, "disconnect() - executed");
if (bluetoothGatt != null) {
if (characteristic != null) {
bluetoothGatt.setCharacteristicNotification(characteristic, false);
}
//remove device authorization/ bond/ pairing
removeBond(bluetoothGatt);
// disconnect now
bluetoothGatt.disconnect();
bluetoothGatt.close();
Log.d(LOG_TAG, "disconnect() - bluetoothGatt disconnect happened");
}
bluetoothGatt = null;
characteristic = null;
bluetoothConnected = false;
servicesDiscovered = false;
// set device as not bonded anymore
bondedBroadcaster.resetDeviceBonded();
}
/**
* bluetooth nearby devices scan is on
* @return true if scanning is on, false otherwise
*/
public boolean isScanning(){
return (this.bluetoothScanning);
}
/**
* Check bluetooth system state (on or off)
* @return true if system is on, false otherwise
*/
public boolean isEnabled(){
try {
checkBluetooth();
return bluetoothAdapter.isEnabled();
} catch (BluetoothNotEnabledException e) {
return false;
}
}
/**
* Check bluetooth connection
* @return true if connected, false otherwise
*/
public boolean isConnected(){
return (this.bluetoothConnected);
}
/**
* Start bluetooth scan for nearby devices
* @param filters Scan filters that define what devices to scan for
*/
public void startScan(List<ScanFilter> filters)
throws BluetoothNotEnabledException{
checkBluetooth();
// dont run two scans simultaneously
if (isScanning()) {
return;
}
// disconnect previously connected devices
if (isConnected()) {
this.disconnect();
return;
}
// setup bluetooth scanning settings
ScanSettings settings = new ScanSettings.Builder()
.setScanMode(ScanSettings.SCAN_MODE_LOW_POWER)
.build();
// start scanning
this.bluetoothScanning = true;
this.bluetoothScanResults.clear();
this.bluetoothLeScanner = bluetoothAdapter.getBluetoothLeScanner();
// Stops scanning after a pre-defined scan period.
Handler bluetoothHandler = new Handler();
bluetoothHandler.postDelayed(new Runnable() {
@Override
public void run() {
stopScan();
}
}, SCAN_TIMEOUT);
// start scan with default scan callback
this.bluetoothLeScanner.startScan(filters, settings, bluetoothScanCallback);
// we have started successfully the BLE scanning
bluetoothListener.onBluetoothStartScan();
}
/**
* Stop bluetooth scan for nearby devices
*/
public void stopScan(){
if (!bluetoothScanning) {
return;
}
// set app scan state to false
bluetoothScanning = false;
if (bluetoothLeScanner != null) {
bluetoothLeScanner.stopScan(bluetoothScanCallback);
bluetoothLeScanner = null;
}
// we have stopped BLE scanning, call the user's callback
bluetoothListener.onBluetoothStopScan(bluetoothScanResults.values());
}
/**
* Send a message via bluetooth
* @param msg message to send
*/
public void send(String msg) {
if (!bluetoothConnected || characteristic == null){
bluetoothListener.onBluetoothNotConnected();
return;
}
try {
msg = msg.replaceAll(DATA_FILTER_REGEX, "") + TERMINATION_CHAR;
Log.d(LOG_TAG, String.format(Locale.getDefault(),
"Sending message: %s",
msg));
characteristic.setValue(msg.getBytes(CHARSET));
bluetoothGatt.writeCharacteristic(characteristic);
} catch (UnsupportedEncodingException e) {
Log.e(LOG_TAG,
"BluetoothLowEnergy.send: Failed to convert message string to byte array");
}
}
public String getDeviceUUID(){
return deviceUUID;
}
public Activity getActivity(){
return activity;
}
/**
* Check if bluetooth is enabled and working properly
*/
private void checkBluetooth() throws BluetoothNotEnabledException{
if (bluetoothAdapter == null) {
final BluetoothManager bluetoothManager =
(BluetoothManager) activity.getSystemService(Context.BLUETOOTH_SERVICE);
if (bluetoothManager == null){
throw new BluetoothNotEnabledException();
}
bluetoothAdapter = bluetoothManager.getAdapter();
}
// Ensures Bluetooth is available on the device and it is enabled. If not,
// displays a dialog requesting user permission to enable Bluetooth.
if (bluetoothAdapter == null || !bluetoothAdapter.isEnabled()) {
throw new BluetoothNotEnabledException();
}
}
}
避免上述问题的关键方法和功能是：
Thread.sleep(600)removeBond(device)refresh(gatt)gatt.disconnect()gatt.close()