Usecase for needsLayout property?
I'm having a bit of a chicken-egg problem with regards to some
dynamically sized components I'm displaying in my application.
Description:
I have a group with a title that wraps some content and displays a title
above it -- the entire group, including the title must be hidden and
unmanaged when the content it is wrapping is empty, here it is in code:
protected Pane createTitledBlock(final String title, final Node content,
final BooleanExpression visibleCondition) {
return new VBox() {{
setFillWidth(true);
getChildren().add(new Label(title) {{
getStyleClass().add(header);
}});
getChildren().add(content);
if(visibleCondition != null) {
managedProperty().bind(visibleCondition);
visibleProperty().bind(visibleCondition);
}
}};
}
Problem:
When the content becomes available and visibleCondition gets toggled to
true, the content part of the titled group is not yet laid out. This
causes the title to be visible without any content briefly until a
layout pass occurs.
Timeline:
- Group with title is hidden/unmanaged
- The content gets updated and visibleCondition is set to true
- Group with title becomes visible/managed
- Briefly an empty group with title is displayed
- Layout occurs, group with title gets resized
Now, I'm thinking of playing with the needsLayout property and delaying
the making visible/managed of the titled group until needsLayout is
false... however, I have a feeling that won't work as an
unmanaged/hidden group is probably not gonna participate in the layout,
resulting in needsLayout never becoming false again as it is not
visible/managed yet...
Any ideas how I could resolve this, and have the group with title only
visible and managed when it is properly laid out?
Also, has any progress in general been made with regards to
hidden/unmanaged controls and determining their expected size when
they're made visible/managed?
--John
Re: Usecase for needsLayout property?
Hi John,
the problem you described is most likely caused by something else as the
layout pass occurs BEFORE the actual rendering.
Also, you bind managed and visible of the entire VBox, not just the
title. So it's strange that you see Label correctly laid-out, but not
the content.
Can you make some sample and attach it to a JIRA issue, so I can have a
look what's actually happening there?
Thanks,
-Martin
On 06/05/2013 11:29 AM, John Hendrikx wrote:
I'm having a bit of a chicken-egg problem with regards to some
dynamically sized components I'm displaying in my application.
Description:
I have a group with a title that wraps some content and displays a
title above it -- the entire group, including the title must be hidden
and unmanaged when the content it is wrapping is empty, here it is in
code:
protected Pane createTitledBlock(final String title, final Node
content, final BooleanExpression visibleCondition) {
return new VBox() {{
setFillWidth(true);
getChildren().add(new Label(title) {{
getStyleClass().add(header);
}});
getChildren().add(content);
if(visibleCondition != null) {
managedProperty().bind(visibleCondition);
visibleProperty().bind(visibleCondition);
}
}};
}
Problem:
When the content becomes available and visibleCondition gets toggled
to true, the content part of the titled group is not yet laid out.
This causes the title to be visible without any content briefly until
a layout pass occurs.
Timeline:
- Group with title is hidden/unmanaged
- The content gets updated and visibleCondition is set to true
- Group with title becomes visible/managed
- Briefly an empty group with title is displayed
- Layout occurs, group with title gets resized
Now, I'm thinking of playing with the needsLayout property and
delaying the making visible/managed of the titled group until
needsLayout is false... however, I have a feeling that won't work as
an unmanaged/hidden group is probably not gonna participate in the
layout, resulting in needsLayout never becoming false again as it is
not visible/managed yet...
Any ideas how I could resolve this, and have the group with title only
visible and managed when it is properly laid out?
Also, has any progress in general been made with regards to
hidden/unmanaged controls and determining their expected size when
they're made visible/managed?
--John
Re: Usecase for needsLayout property?
Thanks Martin,
I've done my best to quickly extract the code from my application...
however, I cannot reproduce the issue there in a direct fashion --
however, I did discover an issue which may be the reason I see a partial
group, I filed that as RT-30952 (TilePane doesn't appear until after
Stage resized a bit).
Basically, my main application is much more active, and will do a lot
of background stuff, which may trigger more layouts -- that's why there
I may only see the partial group for a moment (flickering when I scroll
through the big list) before it gets displayed completely. In this test
application, I see it much more directly where the group that I want to
see is simply not complete until more action is taken.
I also filed another issue, RT-30951 because the resizing of a Stage is
very jittery (the controls keep moving a bit from their correct
positions when in the process of resizing a Stage)... seems like some
font-metrics or other calculation is not producing repeatable results
resulting in a slightly different layout every time...
--John
On 5/06/2013 13:04, Martin Sladecek wrote:
Hi John,
the problem you described is most likely caused by something else as
the layout pass occurs BEFORE the actual rendering.
Also, you bind managed and visible of the entire VBox, not just the
title. So it's strange that you see Label correctly laid-out, but not
the content.
Can you make some sample and attach it to a JIRA issue, so I can have
a look what's actually happening there?
Thanks,
-Martin
On 06/05/2013 11:29 AM, John Hendrikx wrote:
I'm having a bit of a chicken-egg problem with regards to some
dynamically sized components I'm displaying in my application.
Description:
I have a group with a title that wraps some content and displays a
title above it -- the entire group, including the title must be
hidden and unmanaged when the content it is wrapping is empty, here
it is in code:
protected Pane createTitledBlock(final String title, final Node
content, final BooleanExpression visibleCondition) {
return new VBox() {{
setFillWidth(true);
getChildren().add(new Label(title) {{
getStyleClass().add(header);
}});
getChildren().add(content);
if(visibleCondition != null) {
managedProperty().bind(visibleCondition);
visibleProperty().bind(visibleCondition);
}
}};
}
Problem:
When the content becomes available and visibleCondition gets toggled
to true, the content part of the titled group is not yet laid out.
This causes the title to be visible without any content briefly until
a layout pass occurs.
Timeline:
- Group with title is hidden/unmanaged
- The content gets updated and visibleCondition is set to true
- Group with title becomes visible/managed
- Briefly an empty group with title is displayed
- Layout occurs, group with title gets resized
Now, I'm thinking of playing with the needsLayout property and
delaying the making visible/managed of the titled group until
needsLayout is false... however, I have a feeling that won't work as
an unmanaged/hidden group is probably not gonna participate in the
layout, resulting in needsLayout never becoming false again as it is
not visible/managed yet...
Any ideas how I could resolve this, and have the group with title
only visible and managed when it is properly laid out?
Also, has any progress in general been made with regards to
hidden/unmanaged controls and determining their expected size when
they're made visible/managed?
--John
