Just about done at the hospital, no access to computer right now, will check later, unless Carl already solved it :)

@ron what do you think about an empty input check for your initial case in the change handler? will that stop all the NPEs or just the first one?

@edvin I posted a GridPane example to #282 that uses an add() with the extra colspan and rowspan arguments w/i a row{} row { add( rectangle(0.0, 0.0, 80.0, 40.0) { fill = Color.RED }, 0, 0, 2, 1 )

I give up (for now) I have no idea why this is happening

if I disable the

selectedGroup.itemProperty.onChange

it works

ok I have it working and I hate how I fixed it

@User uploaded a file: Untitled

@User uploaded a file: Untitled

@ron i think you have a problem with cascading updates where your view triggers a model change which automatically updates a view, etc. I'm using MVVM to get around some this type of problem in two variations. 1. The view issues a change, but waits for an update event. The view calls on repository to change items. At the end of the items update, a fileOpened is issued. The view picks up the fileOpened event and updates its own copy of items which is a JavaFX-bound property that can be tied to a ListView. 2. The view updates itself, then optimistically issues a model change. Maintain a list of items for the view which is updated is concert with a model change update. It looks like you have to break the binding temporarily in order to work on the list of items. This might need to be replicated in other areas that use repository items. If you only have one and only one component using the keypass items, then the workaround might be acceptable.

The multiple copies I'm suggesting aren't redundant. My ViewModel items represent screen state which can contain uncommitted changes. The model contains record state which reflects the external data store, although there might be some latency.

I understand what you are saying and I agree. There are only 4 usecases here that I have to take into account : add a group, move a group, delete a group, change a group (only the name and later the icon)

so for now this latch like solution will work

That's the way i do it in plain javafx. @edvin might be able to change the terms of the onChange, but I think it's an anti-pattern to use JavaFX binding and then add in a layer of flags to control the binding. I agree that it's fine as a one-off. I need the more general solution because I always have >1 View+ViewModel interacting with models

its clearly an antipattern, but I see no other way to control this

@User uploaded a file: GridPane Demo w. colspan, rowspan, ColumnConstraints,RowConstraints and commented: @edvin This is the test code I wrote to analyze #282

I am stumped

now I get the NPE in places I actually showed in the screencast, reverting through the commits to find what is wrong

the npe is coming from the onchange listener?

yes

@User uploaded a file: Untitled

as you can see mainController.kt:60 is called twice and that is the onchange listener

it seems that the allentries.predicate is null

this is so weird

hmmz the only thing that is changed is the kotlin plugin

right, found it, fixed it and it was my fault

the title of the Entry was being set too late, so that is fixed

also in a defensive mode the onchange is now:

@User uploaded a file: Untitled

phew I was sweating with this one