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This section contains snippets that were automatically translated from C++ to Python and may contain errors.
The discovery process relies on the Bluetooth Service Discovery Process (SDP). The following steps are required to query the services provided by all contactable Bluetooth devices:
create an instance of
start().def startServiceDiscovery(self): # Create a discovery agent and connect to its signals discoveryAgent = QBluetoothServiceDiscoveryAgent(self) connect(discoveryAgent, SIGNAL(serviceDiscovered(QBluetoothServiceInfo)), self, SLOT(serviceDiscovered(QBluetoothServiceInfo))) # Start a discovery discoveryAgent.start() #... # In your local slot, read information about the found devices def serviceDiscovered(self, service): print("Found service():", service.serviceName()) << '(' << service.device().address().toString() << ')'
By default a minimal service discovery is performed. In this mode, the returned
QBluetoothServiceInfo objects are guaranteed to contain only device and service UUID information. Depending on platform and device capabilities, other service information may also be available. The minimal service discovery mode relies on cached SDP data of the platform. Therefore it is possible that this discovery does not find a device although it is physically available. In such cases a full discovery must be performed to force an update of the platform cache. However for most use cases a minimal discovery is adequate as it is much quicker and other classes which require up-to-date information such as
connectToService() will perform additional discovery if required. If the full service information is required, pass
FullDiscovery as the discoveryMode parameter to
This class may internally utilize
QBluetoothDeviceDiscoveryAgent to find unknown devices.
The service discovery may find Bluetooth Low Energy services too if the target device is a combination of a classic and Low Energy device. Those devices are required to advertise their Low Energy services via SDP. If the target device only supports Bluetooth Low Energy services, it is likely to not advertise them via SDP. The
QLowEnergyController class should be utilized to perform the service discovery on Low Energy devices.
On iOS, this class cannot be used because the platform does not expose an API which may permit access to
QBluetoothServiceDiscoveryAgent related features.
- class PySide6.QtBluetooth.QBluetoothServiceDiscoveryAgent([parent=None])#
Constructs a new
parent. The search is performed via the local default Bluetooth adapter.
Constructs a new
deviceAdapter and with
deviceAdapter for the service search. If
deviceAdapter is default constructed the resulting
QBluetoothServiceDiscoveryAgent object will use the local default Bluetooth adapter.
deviceAdapter is specified that is not a local adapter
error() will be set to
InvalidBluetoothAdapterError . Therefore it is recommended to test the error flag immediately after using this constructor.
On WinRT the passed adapter address will be ignored.
On Android passing any
deviceAdapter address is meaningless as Android 6.0 or later does not publish the local Bluetooth address anymore. Subsequently, the passed adapter address can never be matched against the local adapter address. Therefore the subsequent call to
start() will always trigger
This enum describes errors that can occur during service discovery.
No error has occurred.
The Bluetooth adaptor is powered off, power it on before doing discovery.
Writing or reading from the device resulted in an error.
The passed local adapter address does not match the physical adapter address of any local Bluetooth device.
The operating system requests permissions which were not granted by the user.
An unknown error has occurred.
This enum describes the service discovery mode.
Performs a minimal service discovery. The
QBluetoothServiceInfoobjects returned may be incomplete and are only guaranteed to contain device and service UUID information. Since a minimal discovery relies on cached SDP data it may not find a physically existing device until a
Performs a full service discovery.
This signal is triggered when the service discovery was canceled via a call to
Returns the list of all discovered services.
This list of services accumulates newly discovered services from multiple calls to
start() . Unless
clear() is called the list cannot decrease in size. This implies that if a remote Bluetooth device moves out of range in between two subsequent calls to
start() the list may contain stale entries.
The list of services should always be cleared before the discovery mode is changed.
Returns the type of error that last occurred. If the service discovery is done for a single
remoteAddress() it will return errors that occurred while trying to discover services on that device. If the
remoteAddress() is not set and devices are discovered by a scan, errors during service discovery on individual devices are not saved and no signals are emitted. In this case, errors are fairly normal as some devices may not respond to discovery or may no longer be in range. Such errors are suppressed. If no services are returned, it can be assumed no services could be discovered.
Any possible previous errors are cleared upon restarting the discovery.
This signal is emitted when an
error occurs. The
error parameter describes the error that occurred.
- Return type:
Returns a human-readable description of the last error that occurred during the service discovery.
This signal is emitted when the Bluetooth service discovery completes.
finished() signal this signal will even be emitted when an error occurred during the service discovery. Therefore it is recommended to check the
errorOccurred() signal to evaluate the success of the service discovery discovery.
- Return type:
true if the service discovery is currently active; otherwise returns
false. An active discovery can be stopped by calling
- Return type:
This signal is emitted when the Bluetooth service described by
info is discovered.
QBluetoothServiceInfo parameter may contain a Bluetooth Low Energy service if the target device advertises the service via SDP. This is required from device which support both, classic Bluetooth (BaseRate) and Low Energy services.
- Return type:
Sets the remote device address to
address is default constructed, services will be discovered on all contactable Bluetooth devices. A new remote address can only be set while there is no service discovery in progress; otherwise this function returns false.
On some platforms the service discovery might lead to pairing requests. Therefore it is not recommended to do service discoveries on all devices. This function can be used to restrict the service discovery to a particular device.
This is an overloaded member function, provided for convenience.
Sets the UUID filter to a list containing the single element
uuid. The matching applies to the service’s
Sets the UUID filter to
uuids. Only services matching the UUIDs in
uuids will be returned. The matching applies to the service’s
An empty UUID list is equivalent to a list containing only
Starts service discovery.
mode specifies the type of service discovery to perform.
On some platforms, device discovery may lead to pairing requests.
Stops the service discovery process. The
canceled() signal will be emitted once the search has stopped.
Returns the UUID filter.