How works "property Item ufo: ufo" in root?

[Josz]

Hi all,

I have the next code:

import QtQuick 2.11
import QtQuick.Window 2.11

Window {
    id: root
    visible: true
    width: 640
    height: 480
    title: qsTr("Ovni")

    property int duration: 3000
    property Item ufo: ufo           //How works this here?

    Image {
        anchors.fill: parent
        source: "img/ufo_background.png"
    }

    ClickableImageV3 {
        id: ufo
        x: 20; y: root.height - height
        source: "img/ufo.png"
        onClicked: anim.restart()
    }

    ParallelAnimation {
        id: anim
        NumberAnimation {
            target: ufo
            properties: "y"
            to: 20
            duration: root.duration
        }
        NumberAnimation {
            target: ufo
            properties: "x"
            to: 160
            duration: root.duration
        }
    } //ParallelAnimation

}//root

Please, anybody so kind to explain me how works "property Item ufo: ufo" in root? The program works anyway if I delete it. Which is then the purpose?

Thanks in advance

[sierdzio]

@Josz said in How works "property Item ufo: ufo" in root?:

Please, anybody so kind to explain me how works "property Item ufo: ufo" in root? The program works anyway if I delete it. Which is then the purpose?

If this is your main.qml, then this line has no purpose and can be safely removed. If it is not your main.qml file, then such declaration can be used to expose an internal item to a parent file (a file which includes the current one as component). For such use, however, it is better to use alias:

property alias ufo: ufo 

[Josz]

@sierdzio said in How works "property Item ufo: ufo" in root?:

your main.qml, then this line has no purpose and can be safely removed. If it is not your main.qml file, then such declaration can be used to ex

Thank you very much! A nice day.