class QNearFieldManager¶

The QNearFieldManager class provides access to notifications for NFC events. More…

Synopsis¶

Methods¶

def __init__()
def isEnabled()
def isSupported()
def setUserInformation()
def startTargetDetection()
def stopTargetDetection()

Signals¶

def adapterStateChanged()
def targetDetected()
def targetDetectionStopped()
def targetLost()

Note

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

Detailed Description¶

NFC Forum devices support two modes of communications. The first mode, peer-to-peer communications, is used to communicate between two NFC Forum devices. The second mode, master/slave communications, is used to communicate between an NFC Forum device and an NFC Forum Tag or Contactless Card. The targetDetected() signal is emitted when a target device enters communications range. Communications can be initiated from the slot connected to this signal.

NFC Forum devices generally operate as the master in master/slave communications. Some devices are also capable of operating as the slave, so called Card Emulation mode. In this mode the local NFC device emulates a NFC Forum Tag or Contactless Card.

Applications can connect to the targetDetected() and targetLost() signals to get notified when an NFC Forum Tag enters or leaves proximity. Before these signals are emitted target detection must be started with the startTargetDetection() function. Target detection can be stopped with the stopTargetDetection() function. When the target is no longer required the target should be deleted as other applications may be blocked from accessing the target.

NFC on Linux¶

The Linux NFC project provides software to support NFC on Linux platforms. The neard daemon will allow access to the supported hardware via DBus interfaces. QtNfc requires neard version 0.14 which can be built from source or installed via the appropriate Linux package manager. Not all API features are currently supported. To allow QtNfc to access the DBus interfaces the neard daemon has to be running. In case of problems debug output can be enabled by enabling categorized logging for ‘qt.nfc.neard’.

class AdapterState¶

This enum describes the different states a NFC adapter can have.

Constant

Description

QNearFieldManager.AdapterState.Offline

The nfc adapter is offline.

QNearFieldManager.AdapterState.TurningOn

The nfc adapter is turning on.

QNearFieldManager.AdapterState.Online

The nfc adapter is online.

QNearFieldManager.AdapterState.TurningOff

The nfc adapter is turning off.

Constant	Description
QNearFieldManager.AdapterState.Offline	The nfc adapter is offline.
QNearFieldManager.AdapterState.TurningOn	The nfc adapter is turning on.
QNearFieldManager.AdapterState.Online	The nfc adapter is online.
QNearFieldManager.AdapterState.TurningOff	The nfc adapter is turning off.

__init__([parent=None])¶

Parameters:: parent – QObject

Constructs a new near field manager with parent.

adapterStateChanged(state)¶

Parameters:: state – AdapterState

This signal is emitted whenever the state of the NFC adapter changed.

Note

Currently, this signal is only emitted on Android.

isEnabled()¶

Return type:: bool

Returns true if the device has a NFC adapter and it is turned on; otherwise returns false.

See also

isSupported()

isSupported([accessMethod=QNearFieldTarget.AnyAccess])¶

Parameters:: accessMethod – AccessMethod
Return type:: bool

Returns true if the underlying device has a NFC adapter; otherwise returns false. If an accessMethod is given, the function returns true only if the NFC adapter supports the given accessMethod.

See also

isEnabled()

setUserInformation(message)¶

Parameters:: message – str

Sets the message that the system shows to the user. If target detection is running, the message will be updated immediately and can be used as a progress message. The last message set before a call to startTargetDetection() without an error message is used as a success message. If target detection is not running, the message will be used as the initial message when the next detection is started. By default, no message is shown to the user.

Note

Currently, this function only has an effect on iOS because the system shows a popup during the scan. On iOS, this message is mapped to the alert message which is shown upon successful completion of the scan. Other platforms will ignore message.

startTargetDetection(accessMethod)¶

Parameters:: accessMethod – AccessMethod
Return type:: bool

Starts detecting targets and returns true if target detection started successfully; otherwise returns false. Causes the targetDetected() signal to be emitted when a target is within proximity. Only tags with the given accessMethod will be reported. Target detection continues until stopTargetDetection() is called.

To detect targets with a different accessMethod, stopTargetDetection() must be called first.

Note

On iOS, it is impossible to start target detection for both NdefAccess and TagTypeSpecificAccess at the same time. So if AnyAccess is selected, NdefAccess will be used instead.

Note

On platforms using neard, target detection will stop as soon as a tag has been detected.

See also

stopTargetDetection()

stopTargetDetection([errorMessage=""])¶

Parameters:: errorMessage – str

Stops detecting targets. The targetDetected() signal will no longer be emitted until another call to startTargetDetection() is made. Targets detected before are still valid.

Note

On iOS, detected targets become invalid after this call (e.g. an attempt to write or read NDEF messages will result in an error).

If an errorMessage is provided, it is a hint to the system that the application’s goal was not achieved. The errorMessage and a matching error icon are shown to the user. Calling this function with an empty errorMessage implies a successful end of operation; otherwise, an errorMessage should be passed to this function.

Note

Currently, errorMessage only has an effect on iOS because the system shows a popup during the scan where the errorMessage is visible. Other platforms will ignore this parameter.

See also

setUserInformation()

targetDetected(target)¶

Parameters:: target – QNearFieldTarget

This signal is emitted whenever a target is detected. The target parameter represents the detected target.

This signal will be emitted for all detected targets.

QNearFieldManager maintains ownership of target, however, it will not be destroyed until the QNearFieldManager destructor is called. Ownership may be transferred by calling setParent().

Do not delete target from the slot connected to this signal, instead call deleteLater().

Note

that if target is deleted before it moves out of proximity the targetLost() signal will not be emitted.

See also

targetLost()

targetDetectionStopped()¶

This signal is emitted whenever the target detection is stopped.

Note

Mostly this signal is emitted when stopTargetDetection() has been called. Additionally the user is able to stop the detection on iOS within a popup shown by the system during the scan, which also leads to emitting this signal.

targetLost(target)¶

Parameters:: target – QNearFieldTarget

This signal is emitted whenever a target moves out of proximity. The target parameter represents the lost target.

Do not delete target from the slot connected to this signal, instead use deleteLater().

See also

disconnected()