QBluetoothServiceDiscoveryAgent Class

void MyClass::startServiceDiscovery()
{

    // Create a discovery agent and connect to its signals
    QBluetoothServiceDiscoveryAgent *discoveryAgent = new QBluetoothServiceDiscoveryAgent(this);
    connect(discoveryAgent, SIGNAL(serviceDiscovered(QBluetoothServiceInfo)),
            this, SLOT(serviceDiscovered(QBluetoothServiceInfo)));

    // Start a discovery
    discoveryAgent->start();

    //...
}

// In your local slot, read information about the found devices
void MyClass::serviceDiscovered(const QBluetoothServiceInfo &service)
{
    qDebug() << "Found new service:" << service.serviceName()
             << '(' << service.device().address().toString() << ')';
}

Member Function Documentation

QBluetoothServiceDiscoveryAgent::QBluetoothServiceDiscoveryAgent(QObject *parent = nullptr)

Constructs a new QBluetoothServiceDiscoveryAgent with parent. The search is performed via the local default Bluetooth adapter.

QBluetoothServiceDiscoveryAgent::QBluetoothServiceDiscoveryAgent(const QBluetoothAddress &deviceAdapter, QObject *parent = nullptr)

Constructs a new QBluetoothServiceDiscoveryAgent for deviceAdapter and with parent.

It uses deviceAdapter for the service search. If deviceAdapter is default constructed the resulting QBluetoothServiceDiscoveryAgent object will use the local default Bluetooth adapter.

If a 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.

Note: On WinRT the passed adapter address will be ignored.

See also error().

[virtual] QBluetoothServiceDiscoveryAgent::~QBluetoothServiceDiscoveryAgent()

Destructor for QBluetoothServiceDiscoveryAgent

[signal] void QBluetoothServiceDiscoveryAgent::canceled()

This signal is triggered when the service discovery was canceled via a call to stop().

[slot] void QBluetoothServiceDiscoveryAgent::clear()

Clears the results of previous service discoveries and resets uuidFilter(). This function does nothing during an ongoing service discovery (see isActive()).

See also discoveredServices().

QList<QBluetoothServiceInfo> QBluetoothServiceDiscoveryAgent::discoveredServices() const

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.

Note: The list of services should always be cleared before the discovery mode is changed.

See also clear().

QBluetoothServiceDiscoveryAgent::Error QBluetoothServiceDiscoveryAgent::error() const

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 surpressed. If no services are returned, it can be assumed no services could be discovered.

[signal] void QBluetoothServiceDiscoveryAgent::error(QBluetoothServiceDiscoveryAgent::Error error)

This signal is emitted when an error occurs. The error parameter describes the error that occurred.

Note: Signal error is overloaded in this class. To connect to this signal by using the function pointer syntax, Qt provides a convenient helper for obtaining the function pointer as shown in this example:

connect(bluetoothServiceDiscoveryAgent, QOverload<QBluetoothServiceDiscoveryAgent::Error>::of(&QBluetoothServiceDiscoveryAgent::error),
    [=](QBluetoothServiceDiscoveryAgent::Error error){ /* ... */ });

QString QBluetoothServiceDiscoveryAgent::errorString() const

Returns a human-readable description of the last error that occurred during the service discovery.

[signal] void QBluetoothServiceDiscoveryAgent::finished()

This signal is emitted when the Bluetooth service discovery completes.

Unlike the QBluetoothDeviceDiscoveryAgent::finished() signal this signal will even be emitted when an error occurred during the service discovery. Therefore it is recommended to check the error() signal to evaluate the success of the service discovery discovery.

bool QBluetoothServiceDiscoveryAgent::isActive() const

Returns true if the service discovery is currently active; otherwise returns false. An active discovery can be stopped by calling stop().

QBluetoothAddress QBluetoothServiceDiscoveryAgent::remoteAddress() const

Returns the remote device address. If setRemoteAddress() is not called, the function will return a default constructed QBluetoothAddress.

See also setRemoteAddress().

[signal] void QBluetoothServiceDiscoveryAgent::serviceDiscovered(const QBluetoothServiceInfo &info)

This signal is emitted when the Bluetooth service described by info is discovered.

Note: The passed 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.

See also QBluetoothDeviceInfo::coreConfigurations().

bool QBluetoothServiceDiscoveryAgent::setRemoteAddress(const QBluetoothAddress &address)

Sets the remote device address to address. If 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.

See also remoteAddress().

void QBluetoothServiceDiscoveryAgent::setUuidFilter(const QList<QBluetoothUuid> &uuids)

Sets the UUID filter to uuids. Only services matching the UUIDs in uuids will be returned. The matching applies to the service's ServiceId and ServiceClassIds attributes.

An empty UUID list is equivalent to a list containing only QBluetoothUuid::PublicBrowseGroup.

See also uuidFilter().

void QBluetoothServiceDiscoveryAgent::setUuidFilter(const QBluetoothUuid &uuid)

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 ServiceId and ServiceClassIds attributes.

See also uuidFilter().

[slot] void QBluetoothServiceDiscoveryAgent::start(QBluetoothServiceDiscoveryAgent::DiscoveryMode mode = MinimalDiscovery)

Starts service discovery. mode specifies the type of service discovery to perform.

On some platforms, device discovery may lead to pairing requests.

See also DiscoveryMode.

[slot] void QBluetoothServiceDiscoveryAgent::stop()

Stops the service discovery process. The canceled() signal will be emitted once the search has stopped.

QList<QBluetoothUuid> QBluetoothServiceDiscoveryAgent::uuidFilter() const

Returns the UUID filter.

See also setUuidFilter().