如何在android后台运行蓝牙连接？

<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />

BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (bluetoothAdapter == null) {
    // 设备不支持蓝牙
    return;
}

if (!bluetoothAdapter.isEnabled()) {
    Intent enableBluetoothIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
    startActivityForResult(enableBluetoothIntent, REQUEST_ENABLE_BLUETOOTH);
}

bluetoothAdapter.startDiscovery();

private final BroadcastReceiver bluetoothReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (BluetoothDevice.ACTION_ACL_CONNECTED.equals(action)) {
            // 蓝牙设备已连接
        } else if (BluetoothDevice.ACTION_ACL_DISCONNECTED.equals(action)) {
            // 蓝牙设备已断开连接
        }
    }
};

BluetoothDevice device = bluetoothAdapter.getRemoteDevice(deviceAddress);
BluetoothGatt gatt = device.connectGatt(context, false, gattCallback);

private final BluetoothGattCallback gattCallback = new BluetoothGattCallback() {
    @Override
    public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
        if (newState == BluetoothProfile.STATE_CONNECTED) {
            // 蓝牙设备已连接
        } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
            // 蓝牙设备已断开连接
        }
    }

    @Override
    public void onServicesDiscovered(BluetoothGatt gatt, int status) {
        // 发现蓝牙设备的服务
    }

    @Override
    public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
        // 读取蓝牙设备的特征值
    }

    @Override
    public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
        // 写入蓝牙设备的特征值
    }
};