How to initiate a binding property updating by change another property from javascript?

DenisFromNN

Hello

I have some QML sample which sets a source of image and automatically changes its width and I want the width of parent has been also updated without explicit intervention

import QtQuick 2.3
import QtQuick.Controls 1.3

Item {
    width: 300; height: 300
    Item
    {
        id: item
        width: element.width
        height: element.height

        Column
        {
            id: element
            Image
            {
                id: image
            }
            Label
            {
                id: label
                text: "K"
            }
        }

        Component.onCompleted:
        {
            console.log ("Width item: " + item.width + " element: " + element.width + " image: " + image.width + " label: " + label.width)
            image.source = "img.bmp"
            console.log ("Width item: " + item.width + " element: " + element.width + " image: " + image.width + " label: " + label.width)
        }
    }
}

Console output shows that width of image is updated, but width of column (named "element") don't. How to do it automatically updated?

xargs1

This post is deleted!

chrisadams

You should be able to do this declaratively, by declaring either:

width: image.width

OR

width: childrenRect.width

for the "element" column.

Note that this will "bind" the values. Binding is automatic in QML declarations. If you wish to bind from an imperative statement (ie, from within a JavaScript function) you can use:

width = Qt.binding(function() { image.width });

Hope this helps!