In a larger program you might not have a strict one-to-one correspondence between model object and view model object

Can you expand on what you mean by that?

I think what he is saying is, you maybe want to display more than the data from a single domain object / database entity in one view/fragment/table-row/form. Take a user edit form for example. It might display the username, firstname, lastname along with the users address. But in terms of domain objects those could be 2 different objects types from 2 different REST endpoints, one for the naming stuff and one for the address. So you would have one (item)viewmodel binding to data from 2 pojos/data classes.

@carlw @elexx that totally makes sense! although I should rephrase - is the reasoning I surmised for even using one pojo/data class on top of the

ViewModel

accurate?

I definitely was not aware of that though, it's pretty cool

Not sure if I got you right. The backing data classes/pojos are needed to store the actual data. The viewmodel is only an aggregation and representation of what is shown in the view. But when actually changing data, the flow is something like this, I think: user enters data, it gets written to the viewmodel, when committing, the viewmodel validates the input (if validators are attached) and writes the data to the backing pojo/object.

And for showing new data the viewmodel helps you too. You just have to bind the viewmodel once to the fields and only need to replace the backing pojo/object to display new data. Without the viewmodel you would have to rebind all the fields on every pojo/object change, but I think this aspect is quite well explained in the docs: https://edvin.gitbooks.io/tornadofx-guide/content/part1/11.%20Editing%20Models%20and%20Validation.html

@amanda.hinchman-dominguez the examples sometimes show a simple domain model. Those layers can be collapsed if they don’t add value. Sometimes apps have > 100 domain objects and dozens of views. You might show one domain object across two views. A view might show two domain objects. You also may be assuming completely new development. Legacy code can bring an impedance into the picture. This legacy code might need massaging to get it into something usable.

Hellow @carlw it is possible to start second app from the first one. Or open view in a window wich will be live after first one closed?

@iLobanov I implement a requirement like this with a separate executive process that will launch the FX app. I don't think there's anything specific in the framework that helps with this though.

so, there's something always running in the background.

Anybody :) I have some ugly idea, main concept of which is: 1) on opening, if data isn’t set yet, I’m asking for first rows, adding them to the list and scrolling to the bottom. 2) if new row appears and view is on screen with last object on the bottom already - after adding new rows to the list automatically scroll. 3) if users view reached top of the list - ask server for old data using offsets in request I could want to have a button with ‘get more’ title always on the very top of the list, but dunno how to add such an objects and keep them there

@carlw I see. So for example for windows I sould to start a windows service and start App via it?

it could be a service or just a task. start a simple main() that calls exec("java myjavafx app")

Then when you quit the FX app, you'll do a "soft exit" of just the FX executable. you'll want to communicate bi-directionally so that you can issue a complete shutdown command.

you can communicate using a socket or a flat file

Sockets are faster imho

The only interp comm faster

Thx!) Simple enough.

@chickenfresh the approach I posted the other day with the scrollTo call can perpetually make your listview show the last item. It interfered with the solution to fetch more data however. I'm keying on the last item shown to get more data which was running through the data set.

there's a UI action that's missing on the desktop app. on mobile, you scroll as you do with ListView. Making an over-emphasized drag is what is keying the fetch.

@edvin What do you think about a drag event on the ListView or Scene that could capture a refresh cue?

I’ve rewritten your solution for my purposes already, as I’ve updated my post

Some changes with conditions in

if

mainly

At least I have information about first and last objects visible

my solution with they layoutY hack was for the case where there was a huge number of drop down list values that needed to be lazy loaded for performance. trying out a drag to fetch event...

Actually, before you answered with solution on SOF, I’ve also tried with layoutY 😂

But didn’t recognize I need scrollablewrapper data class

Hope it would be supported by framework itself anytime soon, now it works laggy :(