How to keep QML code seperate from QML UI
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Hi there,
I,m a new QT developer and want to know how should i keep qml logic separate from qml ui?
For example one qml file contains all the functions, while ui qml file simplye include function file and references in a way its written in same file like Button {onClicked: functionFromLogicFile()}Please advise
Thanks
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You can import JavaScript file from QML, see here: http://doc.qt.io/qt-5/qtqml-javascript-imports.html
The Samegame example use this method: http://doc.qt.io/qt-5/qtquick-tutorials-samegame-samegame3-example.html
Or you can simply put all the functions in a QML component file, and declare it as singleton, to avoid creating a component each time you need to use a function. Here is an example for styling QML: http://wiki.qt.io/Qml_Styling#Approach_2:_Style_Singleton
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Implement the logic in C++, declare the UI in QML, and glue the pieces together with a minimal amount of JS. You'll get a clean separation and great performance. ;)
Integrating C++ and QML is a matter of implementing C++ types that expose to QML:
- properties
- signals
- slots / invokable methods
You can access all these in QML, providing you the necessary tools to communicate between C++ and QML. Notice that there is rarely need to use
QObject::findChild()and friends to dig into the hierarchy of QML objects and start manipulating them from C++. Instead, just emit signals from C++ when properties change and relevant events occur.The correct way to register a C++ type to QML basically depends on how it should be instantiated:
- a creatable QML type, such as Item:
qmlRegisterType() - a QML singleton type, such as LocalStorage, instantiated by the QML engine on demand:
qmlRegisterSingletonType() - an existing instance created in C++ exposed to QML:
QQmlContext::setContextProperty()
