Little worried about the ListView/TreeView/TableView classes

John Hendrikx hjohn at
Mon Jul 9 15:51:45 PDT 2012

My program relies extensively on the *View classes, however, there are 
numerous little problems with these (JavaFX 2.2b13) that I'm considering 
rewriting these controls myself to "take control" and being able to fix 

Many of the issues I've reported as bugs, which are all in the process 
of being deferred to JFX3.0 (if I understand correctly), which is 
scheduled for over a year from now.

Here is a list of problems I've been running into just this past week -- 
and I've reported several others.  Most of these apply to any of the 
*View classes, but some may be specific to one of the types.

- Calling requestFocus() behaves differently from clicking with 
mouse/tabbing when
using only keyboard navigation:

Left Mouse Click:
Current focusowner : VirtualFlow[id=virtual-flow, styleClass=]
Current focusowner : ListView[id=null, styleClass=list-view]

Tabbing to it:
Current focusowner : ListView[id=null, styleClass=list-view]

Programmatic requestFocus() immediately after ListView added to Scene:
Current focusowner : ListView at 1966198[styleClass=list-view]

Why is it not the same?  This seems to be causing issues sometimes where 
the ListView
is not properly activated and it is not accepting keyboard input 
(despite being the
focusowner as printed above).

- Sometimes ListView starts highlighting every Xth cell when scrolling 
through list

Scrolling through a ListView using the cursor keys one can get the 
ListView stuck to
highlighting only the Xth cell (where X seems to be in the range of the 
number of active
Cells).  When there is only few items in the list this bug manifests 
itself as not
changing the focus of the item at all (ie, the wrong cell is 
highlighted).  Usually a
mouse click on a random item fixes this bug again, but sometimes even 
that doesn't work.

This bug is incredibly hard to reproduce but the frequency of it can be 
by using a ScrollBar Skin that breaks the rule that getNode() should 
always return the
same item.  It however happens with the default ScrollBar Skin as well, 
just much much
rarer.  I have a test case with a contract-breaking ScrollBar Skin that 
manages to
reproduce it almost every time.

- Page up broken when used at bottom of ListView

Scroll down fully with page down.  Now page up, notice that it goes up 
one page, but the
next page up only goes up one item for a few times (about a page worth 
of items) before
starting to act like a real page up again.

- Pressing Cursor Left/Right on an active ListView changes focus despite 
keys being consumed

Despite having a handler in setOnKeyPressed that consumes the Cursor 
keys (to do something
useful with them) the focus still also changes (ie, it triggers my 
action AND affects
a focus change).  I can block them with an EventFilter, but would rather 
allow users of
my custom control to still being able to register these keys for special 

- Numerous scrollTo bugs

Poor centering when scrolling to an item (sometimes even outside view 
port); not responding
at all when called at inoppertune times (right after populating and 
adding to scene); unable
to precisely save/restore view position; creating cells for every item 
from 0 to item being
scrolled to... and recently (since 2.2betas) completely failure to draw 
the ListView at all
(can take various forms, only scrollbars drawn, somtimes the entire 
container is missing).
Restores itself on any ListView redrawing activity, like selecting cell, 
scrolling with cursor
keys, etc..

- Numerous focus/select bugs

Similar to above, when these things occur in rapid succession (ListView 
added to Scene,
populated, correct item selected, scrolled to saved position) it happens 
frequently that no
cell gets highlighted at all (or perhaps the wrong one is highlighted 
but not visible at
the current scroll position)

- Cells are sometimes a pixel different in height

Haven't been able to find a pattern to this yet, it happens with the 
default cell renderer
when it is styled with some fancy borders.  Very noticable when holding 
cursor down because
the borders jitter (create a border with an inset of 1 or 2 pixels so 
there should be a fixed
gap between the cells, the gap will sometimes be a pixel larger than usual).

It doesn't seem to be content related as a cell that is a pixel too 
large in the upper half
of the ListView can appear regular size in the bottom half of the ListView.


There are probably more I forgot to list or already worked around and 
forgot about (I seem
to remember constructing a ListView, not adding it to Scene, but 
populating it and selecting
an item and calling scrollTo, and THEN adding it to the Scene works very 
poorly as well).

Anyway... I'm a bit worried that fixes for these are now over a year 
away... I don't really need
much (just a scrollbar, some same height, same width custom cells, 
nicely stacked on top of each
other reacting to cursor input) but I just keep running into above 
problems during normal use
of the app.

Can I help get these debugged or am I on my own?


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