[Qt-qml] question about how to assign a delegate

[Johannes Zellner]

Hi,

On 12/28/2011 10:52 AM, ext Sivan Greenberg wrote:
> Hi All,
>
>   I've been recently playing with the wonderful RSS reader example that
> is shipped with Creator part of the SDK, and I noticed (in contrast
> with old examples) that the delegates in the example are assigned as
> such:
>
>      ListView {
>                  focus: true
>                  id: categories
>                  anchors.fill: parent
>                  model: rssFeeds
>                  footer: quitButtonDelegate
>                  delegate: CategoryDelegate {}
>                  highlight: Rectangle { color: "steelblue" }
>                  highlightMoveSpeed: 9999999
>              }
>
> Notice the {} braces after the delegate assignment, now with the the
> braces the listview shows no content, so they are required. Has this
> changed in QML over the last months or just something I overlooked ?
> What's the semantic meaning of that? Perhaps this means to
> "instantiate" the delegate and have the delegate property reference
> it? (Much like you do in Python, where you do obj = Object())
As you already suspected, the "CategoryDelegate{}" in this case means, 
that an instance of this Component will be created and assigned to the 
delegate property. Without the braces, it tries to find an instance of a 
Component with the "id: CategoryDelegate".
In this case for the "footer" it references "quitButtonDelegate" by ID.

Johannes