android BLE扫描、连接、切断的代码

以下是Android BLE的简单示例代码，包括扫描、连接和断开连接：

#### 扫描设备

private BluetoothAdapter mBluetoothAdapter;
private boolean mScanning;
private Handler mHandler;

// Stops scanning after 10 seconds.
private static final long SCAN_PERIOD = 10000;

// Initializes Bluetooth adapter.
final BluetoothManager bluetoothManager =
        (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
mBluetoothAdapter = bluetoothManager.getAdapter();

// Checks if Bluetooth is supported on the device.
if (mBluetoothAdapter == null) {
    Toast.makeText(this, "Bluetooth is not supported on this device", Toast.LENGTH_SHORT).show();
    finish();
    return;
}

// Ensures Bluetooth is enabled on the device. If Bluetooth is not currently
// enabled, fire an intent to display a dialog asking the user to grant
// permission to enable it.
if (!mBluetoothAdapter.isEnabled()) {
    Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
    startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
} else {
    scanLeDevice(true);
}

// Handles various events fired by the Service.
// ACTION_GATT_CONNECTED: connected to a GATT server.
// ACTION_GATT_DISCONNECTED: disconnected from a GATT server.
// ACTION_GATT_SERVICES_DISCOVERED: discovered GATT services.
// ACTION_DATA_AVAILABLE: received data from the device.  This can be a result of read
//                        or notification operations.
private final BroadcastReceiver mGattUpdateReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        final String action = intent.getAction();
        if (BluetoothLeService.ACTION_GATT_CONNECTED.equals(action)) {
            // Update UI
        } else if (BluetoothLeService.ACTION_GATT_DISCONNECTED.equals(action)) {
            // Update UI
        } else if (BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED.equals(action)) {
            // Update UI
        } else if (BluetoothLeService.ACTION_DATA_AVAILABLE.equals(action)) {
            // Update UI
        }
    }
};

// Stops scanning after a pre-defined scan period.
private void scanLeDevice(final boolean enable) {
    if (enable) {
        // Stops scanning after a pre-defined scan period.
        mHandler.postDelayed(new Runnable() {
            @Override
            public void run() {
                mScanning = false;
                mBluetoothAdapter.stopLeScan(mLeScanCallback);
            }
        }, SCAN_PERIOD);

        mScanning = true;
        mBluetoothAdapter.startLeScan(mLeScanCallback);
    } else {
        mScanning = false;
        mBluetoothAdapter.stopLeScan(mLeScanCallback);
    }
}

// Device scan callback.
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() {
                        // Process scan results here.
                    }
                });
            }
        };

#### 连接设备

private BluetoothLeService mBluetoothLeService;
private boolean mConnected = false;

private final ServiceConnection mServiceConnection = new ServiceConnection() {

    @Override
    public void onServiceConnected(ComponentName componentName, IBinder service) {
        mBluetoothLeService = ((BluetoothLeService.LocalBinder) service).getService();
        if (!mBluetoothLeService.initialize()) {
            Log.e(TAG, "Unable to initialize Bluetooth");
            finish();
        }
        // Automatically connects to the device upon successful start-up initialization.
        mBluetoothLeService.connect(mDeviceAddress);
    }

    @Override
    public void onServiceDisconnected(ComponentName componentName) {
        mBluetoothLeService = null;
    }
};

// Code to manage Service lifecycle.
@Override
protected void onResume() {
    super.onResume();
    registerReceiver(mGattUpdateReceiver, makeGattUpdateIntentFilter());
    if (mBluetoothLeService != null) {
        final boolean result = mBluetoothLeService.connect(mDeviceAddress);
        Log.d(TAG, "Connect request result=" + result);
    }
}

@Override
protected void onPause() {
    super.onPause();
    unregisterReceiver(mGattUpdateReceiver);
}

@Override
protected void onDestroy() {
    super.onDestroy();
    unbindService(mServiceConnection);
    mBluetoothLeService = null;
}

private static IntentFilter makeGattUpdateIntentFilter() {
    final IntentFilter intentFilter = new IntentFilter();
    intentFilter.addAction(BluetoothLeService.ACTION_GATT_CONNECTED);
    intentFilter.addAction(BluetoothLeService.ACTION_GATT_DISCONNECTED);
    intentFilter.addAction(BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED);
    intentFilter.addAction(BluetoothLeService.ACTION_DATA_AVAILABLE);
    return intentFilter;
}

#### 断开连接

if (mBluetoothLeService != null) {
    mBluetoothLeService.disconnect();
    mBluetoothLeService.close();
}
mConnected = false;