Layouts with constraint classes

[Tom Eugelink]

Not variables, but references. There are constraints specified for nodes that are not yet part of a layout (or even exist at that time, because they are declared further down). Note the absense of a label in the first HBox.C.

<HBox>
     <HBox.C for="arrow" vgrow="NEVER"  valignment="RIGHT"/>
</HBox>

<HBox>
     <Label  fx:id="arrow"  alignment="center" text="">
         <HBox.C vgrow="ALWAYS"  valignment="LEFT" maxWidth="Infinity"/>
     <Label>
</HBox>


Tom


On 2012-11-30 14:11, Daniel Zwolenski wrote:
> Ah ok, from your example code it looks like you want to use variables in FXML to define your constraints - getting into that territory of CSS-like style definitions that Richard was talking about?
>
> Assuming this is what you want, this can be done in the current setup using the ridiculously under-documented <fx:define> thing.
>
> I knocked up a very rough sample for you quickly. The FXML looks like this:
>
>   <BorderPane xmlns:fx="http://javafx.com/fxml">
>
>     <fx:define>
>         <HBoxConstraints fx:id="noGrow" hgrow="NEVER"/>
>         <HBoxConstraints fx:id="growLots" hgrow="ALWAYS"/>
>     </fx:define>
>
>     <center>
>         <HBox>
>             <Label text="I don't grow" style="-fx-background-color:green" Constraints.constraints="$noGrow"/>
>             <Label text="I grow big" style="-fx-background-color:yellow" Constraints.constraints="$growLots"/>
>         </HBox>
>     </center>
>
>   </BorderPane>
>
> (see https://code.google.com/p/zenjava-playtime/source/browse/trunk/layouts/src/main/resources/fxml/example.fxml)
>
> I made a base Constraints class with a static helper method on it (called via "Constraints.constraints" in the FXML above):
> https://code.google.com/p/zenjava-playtime/source/browse/trunk/layouts/src/main/java/com/playtime/layouts/Constraints.java
>
> And then a specific instance of HBoxConstraints:
> https://code.google.com/p/zenjava-playtime/source/browse/trunk/layouts/src/main/java/com/playtime/layouts/HBoxConstraints.java
>
> Obviously you would add others, like VBoxConstraints, GridPaneConstraints, etc. All pretty trivial. These helper classes could easily be included in something like JFXtras.
>
> So I stick with the stance that FXML is more or less OK here (not to say I wouldn't improve it lots in other areas), and really your conversation is about the Java API which is nicely decoupled to what can/can't be done in FXML. Kudos to Richard and the JFX team for designing the builders right.
>
>
>
>
> On Fri, Nov 30, 2012 at 9:20 PM, Tom Eugelink <tbee at tbee.org <mailto:tbee at tbee.org>> wrote:
>
>     On 2012-11-30 10:59, Daniel Zwolenski wrote:
>
>         It just doesn't do it the exact way you suggest where you specify multiple possibilities directly in the child in case it ends up in a different parent - not an approach I agree with anyway (see my previous comments), but that's just my opinion.
>
>
>     Just to make sure my suggestion is not misunderstood, it does not specify multiple possibilities in the child, but in the layout.
>
>     <HBox>
>         <HBox.C for="arrow" vgrow="NEVER"  valignment="RIGHT"/>
>     </HBox>
>
>     <HBox>
>         <Label  fx:id="arrow"  alignment="center" text="">
>             <HBox.C vgrow="ALWAYS"  valignment="LEFT" maxWidth="Infinity"/>
>         <Label>
>     </HBox>
>
>