import QtQuick
import QtQuick.Controls.Basic

Window {
    width: 640
    height: 480
    visible: true

    ProgressBar {
        id: prog
        anchors.centerIn: parent
        value: 0.5
    }

    Component.onCompleted: {
        prog.background.color = "cyan"
        prog.contentItem.color = "yellow"
    }

    Button {
        text: "Update"
        onClicked: {
            prog.background.color = "magenta"
            prog.contentItem.color = "black"
        }
    }
}