How to Connect C Signals with QString Parameters to QML Slots?

Connecting C Signals to QML Slots

In Qt, communication between C and QML can be achieved by connecting C signals to QML slots. While sending primitive type parameters works seamlessly, sending signals with complex types like QString can result in errors.

Connecting with QString Parameters

To connect a signal carrying a QString to a QML slot, the standard object-to-object connection method using QObject::connect() may not suffice. Instead, utilize Qt's Connections to establish the link.

Procedure:

1. Expose the C Object in QML: Add your C object to the QML file using setContextProperty.

<code class="cpp">qmlVectorForm->rootContext()->setContextProperty("YourObject", myOb);</code>

2. Define the Signal: Your C signal will now look like this:

<code class="cpp">finishedGatheringDataForItem(QString signalString)</code>

3. Add Connections in QML: Establish connections in the QML file:

<code class="qml">Connections {
    target: YourObject
    onFinishedGatheringDataForItem: {
        qmlString = signalString
    }
}</code>

This will create a connection between the finishedGatheringDataForItem signal in C and the onFinishedGatheringDataForItem handler in QML, allowing you to handle the QString parameter effectively.

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