Proposal: Avoiding nested views with a merge tag

[Yennick Trevels]

Indeed, that's it. Which in return should increase performance since the
tree would contain a smaller number of levels (so less layout code that
needs to be executed). This performance is important for desktop
applications, but even more if/when JavaFx is going mobile.


On Mon, Dec 17, 2012 at 5:42 PM, Richard Bair <richard.bair at oracle.com>wrote:

> I see, basically what you want is a fragment in some secondary XML file,
> and since XML requires a root, you want a root which isn't a node so as to
> make XML happy. Is that right?
>
>
> On Dec 17, 2012, at 8:28 AM, Yennick Trevels <yennick.trevels at gmail.com>
> wrote:
>
> ListView isn't what I'm looking for. It's more about a general way to
> reduce the number of levels in the scene graph (which I called display
> list). The blog post I mentioned describes quite clearly what I'm aiming it.
>
> For example when you have the following:
>
> <?xml version="1.0" encoding="UTF-8"?><VBox xmlns:fx="http://javafx.com/fxml">
>     <children>
>         <MyComponent />
>     </children></VBox>
>
>
>
> *MyComponent.fxml:*
>
> <?xml version="1.0" encoding="UTF-8"?><VBox xmlns:fx="http://javafx.com/fxml">
>   <children>
>     <TextField />
>     <Button />
>   </children></VBox>
>
>
> This would create the following tree in the scene graph:
> VBox
>   |---->VBox
>              |----->TextField
>              |----->Button
>
> So basically the child VBox is unnecessary and only creates an extra level
> in the scene graph without adding any functionality because the TextField
> and Button would already be aligned vertically by the top VBox. That's
> where the merge tag comes in which could replace the VBox tag in the
> MyComponent.fxml view. Then the tree would look like this:
>
> VBox
>      |----->TextField
>      |----->Button
>
>
> I hope this explains it somewhat clearly :)
>
>
> On Mon, Dec 17, 2012 at 4:43 PM, Richard Bair <richard.bair at oracle.com>wrote:
>
>> In fx there is not a display list, and nodes cannot be repeated in the
>> scene graph, so you have to have the duplicate hbox.
>>
>> ListView is a powerful tool for doing virtualized views, maybe that is
>> what you need? What is the use case?
>>
>> On Dec 17, 2012, at 7:03 AM, Yennick Trevels <yennick.trevels at gmail.com>
>> wrote:
>>
>> > But if I understand this tag correctly it will still create an instance
>> of
>> > HBox? So this root tag will still create a container (which will be
>> added
>> > as a Node to the displaylist), which may be unnecessary.
>> > Is it possible with this tag to not create a node in the displaylist, so
>> > that elements defined under the root tag are added to the container in
>> > which the fxml view is being used?
>> >
>> >
>> > On Mon, Dec 17, 2012 at 3:45 PM, Tom Schindl <
>> tom.schindl at bestsolution.at>wrote:
>> >
>> >> Isn't that what
>> >>
>> >> <fx:root xmlns:fx="http://javafx.com/fxml" type="HBox">
>> >> </fx:root>
>> >>
>> >> is good for?
>> >>
>> >> Tom
>> >>
>> >> Am 17.12.12 15:40, schrieb Yennick Trevels:
>> >>> One of the most common performance problems in RIA frameworks is
>> having a
>> >>> deeply nested component tree. One of the reasons is the use of xml for
>> >>> declaring the layout (fxml in case of JavaFx). The problem with xml is
>> >> that
>> >>> when you want to group multiple components in a separate fxml for
>> reuse
>> >>> purposes, you have to define a root tag, which in most frameworks will
>> >>> create an extra (potentially unnecessary) node in the displaylist.
>> >>>
>> >>> The way Android has solved this is by using a <merge> tag, which
>> doesn't
>> >>> create an extra node in the displayList. A good overview of this tag
>> can
>> >> be
>> >>> found here:
>> >>
>> http://android-developers.blogspot.com/2009/03/android-layout-tricks-3-optimize-by.html
>> >>>
>> >>> Imo such a tag is something which can also be very useful for JavaFx
>> >> since
>> >>> it's also node-based, certainly since performance is key in RIA
>> >>> applications.
>> >>>
>> >>> Is something like this already in development and if not, what are
>> your
>> >>> thoughts about this?
>> >>>
>> >>>
>> >>> Greetz,
>> >>> Yennick
>> >>
>> >>
>> >> --
>> >> B e s t S o l u t i o n . a t                        EDV Systemhaus
>> GmbH
>> >>
>> ------------------------------------------------------------------------
>> >> tom schindl                 geschäftsführer/CEO
>> >>
>> ------------------------------------------------------------------------
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>> 935833
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>> 935834
>> >>
>>
>
>