[Interest] Why is this a binding loop?

[Nuno Santos]

Binding loops sucks, but with some refactoring we always get to an alternative.

Try this:

Rectangle {
	width: parent.width
	height: label.paintedHeight*2
	
	Text {
		id: label
		text: “title
		anchors.centerIn: parent
	}
}

If the binding loops persists maybe the dependency is being caused by anchors.centerIn: parent

Nuno

> On 16 Nov 2016, at 07:41, Elvis Stansvik <elvstone at gmail.com> wrote:
> 
> Den 15 nov. 2016 11:15 em skrev "Jason H" <jhihn at gmx.com <mailto:jhihn at gmx.com>>:
> >
> > Rectangle {
> >         width: parent.width
> >         height: childrenRect.height * 2
> >         Text {
> >                 text: "title"
> >                 anchors.centerIn: parent
> >         }
> > }
> >
> > 'QML Rectangle: Binding loop detected for property "height"'
> >
> > I think that computation should be possible without creating a binding loop?
> 
> I would think so too, but perhaps there's a limitation such that when you use childrenRect in the height expression, a dependency on that property group as a whole (including x and y, which are in turn dependent on the parent height, thus creating a "false" loop) is introduced.
> 
> Though I don't know, that seems like a serious limitation to me, so I'm probably wrong. Just an idea.
> 
> Does it work if you give the Text an id, and use the Text's height explicitly instead of childrenRect.height? (on the bus, so can't test).
> 
> Elvis
> 
> > _______________________________________________
> > Interest mailing list
> > Interest at qt-project.org <mailto:Interest at qt-project.org>
> > http://lists.qt-project.org/mailman/listinfo/interest <http://lists.qt-project.org/mailman/listinfo/interest>
> _______________________________________________
> Interest mailing list
> Interest at qt-project.org
> http://lists.qt-project.org/mailman/listinfo/interest

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.qt-project.org/pipermail/interest/attachments/20161116/ecdf9434/attachment.html>