PyQt QML Material Design button background won't change

Question

I'm new to QML and I'm trying to change the background color of a button but nothing seems to work. Here's the python code: import sys

from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5.QtCore import QUrl
from PyQt5.QtQuick import QQuickView


if __name__ == "__main__":

    app = QApplication(sys.argv)

    view = QQuickView()
    view.setSource(QUrl('basic.qml'))
    view.show()

    sys.exit(app.exec_())

And the basic.qml:

import QtQuick 2.0
import QtQuick.Controls 2.0
import QtQuick.Controls.Material 2.0
import QtQuick.Controls.Material 2.3

Rectangle {
    width:600;height:150;
    color: Material.color(Material.Red)
    Button {
        text: qsTr("Button")
        highlighted: true
        Material.background: Material.Teal
    }
}

Here is how it looks, the button isn't 'Material.Teal' and no matter what color I try it still doesn't work. I've tried it with Pane and other elements but still nothing.

Here's where I got the code: http://doc.qt.io/qt-5/qtquickcontrols2-material.html#material-primary-attached-prop

I've tried it with other styles/methods like pallete (orFusion): https://doc.qt.io/qt-5.10/qml-qtquick-controls2-control.html#palette-prop

Page {
    palette.text: "red"

    Column {
        Label {
            text: qsTr("This will use red color...")
        }

        Switch {
            text: qsTr("... and so will this")
        }
    }
}

Answer 1

In your case there are 2 possible solutions:

---

1. If you want to use Material.background you must establish that the style you are going to use is Material, and to do so you can choose one of the following options:

option 1: add the style through sys.argv:

import sys

from PyQt5.QtGui import QGuiApplication
from PyQt5.QtCore import QUrl
from PyQt5.QtQuick import QQuickView


if __name__ == "__main__":
    sys.argv += ['--style', 'material']
    app = QGuiApplication(sys.argv)

    view = QQuickView()
    view.setSource(QUrl('basic.qml'))
    view.show()

    sys.exit(app.exec_())

option 2: add the style through os.environ():

import os
import sys

from PyQt5.QtGui import QGuiApplication
from PyQt5.QtCore import QUrl
from PyQt5.QtQuick import QQuickView


if __name__ == "__main__":
    app = QGuiApplication(sys.argv)
    os.environ["QT_QUICK_CONTROLS_STYLE"] = "Material"

    view = QQuickView()
    view.setSource(QUrl('basic.qml'))
    view.show()

    sys.exit(app.exec_())

option 3: create a qtquickcontrols2.conf file and load it into the application using a qresource:

qtquickcontrols2.conf

; This file can be edited to change the style of the application
; See Styling Qt Quick Controls 2 in the documentation for details:
; http://doc.qt.io/qt-5/qtquickcontrols2-styles.html

[Controls]
Style=Material

then a resource.qrc is created:

resource.qrc:

<RCC>
    <qresource prefix="/">
        <file>qtquickcontrols2.conf</file>
    </qresource>
</RCC>

Then you must convert the .qrc to .py:

pyrcc5 resource.qrc -o resource_rc.py

and at the end the resource_rc.py file is imported into the main.py

main.py:

from PyQt5.QtGui import QGuiApplication
from PyQt5.QtCore import QUrl
from PyQt5.QtQuick import QQuickView

import sys
import resource_rc

if __name__ == "__main__":
    app = QGuiApplication(sys.argv)
    view = QQuickView()

    view.setSource(QUrl('basic.qml'))
    view.show()
    sys.exit(app.exec_())

---

2. or not use the Material style, and only use their colors through the use of palette:

---

import QtQuick 2.0
import QtQuick.Controls 2.3
import QtQuick.Controls.Material 2.3

Rectangle {
    width:600;height:150;
    color: Material.color(Material.Red)
    Button {
        text: qsTr("Button")
        highlighted: true
        palette.dark: Material.color(Material.Teal)
    }
}