CODEWITHSUNDEEP
qtqmlqtquickcontrols2
Georg Schölly
Georg Schölly

Reputation: 126175

Qt Quick Controls 2 hangs when overwriting Button.qml

I'm trying to implement my own style and for this I want to override the built-in objects. Here's what I'm doing:

// main.cpp
QQuickStyle::setStyle("mystyle");

and

// mystyle/Button.qml
import QtQuick 2.5
import QtQuick.Controls 2.1 as Controls

Controls.Button {
    background: Rectangle {
        color: "green"
    }
}

and

// qml.qrc
<RCC>
    <qresource prefix="/">
        <file>main.qml</file>
        <file>mystyle/CheckBox.qml</file>
    </qresource>
</RCC>

According to the docs I believe this should work automagically using file selectors.

However, my app hangs on startup. My guess is that I fall into a recursive import. How do I do this correctly?

Upvotes: 0

Views: 525

Answers (2)

jpnurmi
jpnurmi

Reputation: 5836

The Qt Quick Controls 2 styling system is based on QML type registration. When you run your app with mystyle, the type known as QtQuick.Controls.Button IS mystyle/Button.qml. Therefore mystyle/Button.qml cannot inherit QtQuick.Controls.Button. It cannot inherit itself.

This is basically the same as writing the following C++:

// button.h
#include "button.h"
class Button : public Button {};

A bit radicalized, but easy to understand analogy. :)

What you can do is to have (My)Button.qml somewhere, let it inherit QtQuick.Controls.Button, and don't register it as a Qt Quick Controls 2 but simply import the folder. This is what we call as "Customizing Qt Quick Controls 2".

Upvotes: 4

Tony Clifton
Tony Clifton

Reputation: 537

  1. The style must be configured before loading QML that imports Qt Quick Controls.It is not possible to change the style after the QML types have been registered. setStyle()

  2. Apply the existing style in your custom style's qml files.

Note: It is recommended to use QQmlApplicationEngine, which internally creates a QQmlFileSelector instance. This is all that is needed to take QML file selectors into use.

See: Creating Custom Styles

Upvotes: 0

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