NDEF Editor Example▲

The NDEF Editor example reads and writes NFC Data Exchange Format (NDEF) messages to NFC Forum Tags. NDEF messages can be composed by adding records of supported types. Additionally, NDEF messages can be loaded/saved from/into a file located in the file system of the machine where the application is running.

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NFC Tag detection▲

The MainWindow class is able to detect if a NFC Tag is in the range for read/write operations. It can also detect if connectivity has been lost. This is achieved by connecting the MainWindow class private handlers to the signals QNearFieldManager::targetDetected and QNearFieldManager::targetLost.

 
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m_manager = new QNearFieldManager(this);
connect(m_manager, &QNearFieldManager::targetDetected,
        this, &MainWindow::targetDetected);
connect(m_manager, &QNearFieldManager::targetLost,
        this, &MainWindow::targetLost);

Through the UI a user requests when to start the detection of a NFC Tag by calling the method QNearFieldManager::startTargetDetection.

 
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m_manager->startTargetDetection();

Once the target is detected the MainWindow connects the following signals to its internal private slots: QNearFieldTarget::ndefMessageRead, QNearFieldTarget::NdefReadError, QNearFieldTarget::ndefMessagesWritten, QNearFieldTarget::NdefWriteError and QNearFieldTarget::error

 
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void MainWindow::targetDetected(QNearFieldTarget *target)
{
    switch (m_touchAction) {
    case NoAction:
        break;
    case ReadNdef:
        connect(target, &QNearFieldTarget::ndefMessageRead, this, &MainWindow::ndefMessageRead);
        connect(target, &QNearFieldTarget::error, this, &MainWindow::targetError);

        m_request = target->readNdefMessages();
        if (!m_request.isValid()) // cannot read messages
            targetError(QNearFieldTarget::NdefReadError, m_request);
        break;
    case WriteNdef:
        connect(target, &QNearFieldTarget::ndefMessagesWritten, this, &MainWindow::ndefMessageWritten);
        connect(target, &QNearFieldTarget::error, this, &MainWindow::targetError);

        m_request = target->writeNdefMessages(QList<QNdefMessage>() << ndefMessage());
        if (!m_request.isValid()) // cannot write messages
            targetError(QNearFieldTarget::NdefWriteError, m_request);
        break;
    }
}

If during the process of reading or writing to a NFC Tag the connection is lost, the MainWindow reacts to this event by scheduling the target deletion (QObject::deleteLater).

 
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void MainWindow::targetLost(QNearFieldTarget *target)
{
    target->deleteLater();
}

Record creation▲

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