JavaFX – exclude/include parent and all its children from layout dynamically - layout

Background/Context:
I have a HBox as a parent and many child Nodes (Buttons, TextFields, Labels…). The HBox is a child of other container (BorderPane/VBox/Grid)
My questions:
How do I dynamically remove/exclude the parent (HBox) and all its children from layout?
I am looking for some three-state property on Node (like in Microsoft WPF):
Visible – visible and participate in layout
Collapsed – is not visible and do not participate in layout (applies to its children as well)
Hidden – is not visible but participate in layout
http://msdn.microsoft.com/en-us/library/ms590101.aspx
What options does JavaFX offer?
My solutions so far:
hBox.setManaged(false);
this work only for HBox, its children are still present
root.getChildren().remove(hBoxTop);
root.getChildren().add(hBoxTop);
Well, this looks like it could work.., but for example in case of root being BorderPane, once I remove/add and remove the HBox, the space after it remains unused. I already tried requestLayout() but id does not force thr rrot to fill it. Am I missing something? Is it correct approach to this problem?
Edited:
Well, I got this working.
Dynamically removing and adding for this specific case can be achieved by:
Remove:
root.setTop(null);
Add:
root.setTop(hBoxTop);
When I did not call setTop(null) on removal, BorderPane still reserved space for HBox (even after removal from its children).
IMHO: it is not very good model as it is parent-container specific. For example if I change, BorderPane to VBox a I had to change these methods as well. For VBox, remove/add on children collection works but I need to remember index so that HBox appears at same place after calling add.

Using root.setTop(null) is not a good idea because as you say it's specific to BorderPane.
I think the best solution is to use:
root.getChildren().remove(yourPane);
And use layout methods to place your other childrens as you want.
But maybe you should not use a BorderPane in the first place with the behaviors you want in your application.
Notice you can also do root.getChildren().clear() to remove all component and add it again to your layout but differently.

Related

What exactly does layout_scrollFlags = "snapMargins" do?

I've read the documentation of this attribute:
An additional flag to be used with 'snap'. If set, the view will be snapped to its top and bottom margins, as opposed to the edges of the view itself.
https://developer.android.com/reference/com/google/android/material/appbar/AppBarLayout.LayoutParams.html#scroll_flag_snap
But I can't observe any actual effect in my app. What margin are they talking about? Every margin on the CollapsingToolbarLayout (on which this attribute is set) completely destroys the layout.
Not sure if it's useful yet, but here is the difference:)
If you pass snap as scroll flag, then it will move your view (in my case this search bar, it's linearLayout) to it's edge NOT INCLUDING the margin_layout
Then I've tried snap|snapMargin and it moved with the margin
P.S. No idea why snapMargin doesn't work without snap ¯\_(ツ)_/¯
This attribute is responsible for a scrolling behavior of AppBarLayout and its children. You can apply it directly to AppBarLayout or on the inside views, in the xml layout of your AppCompatActivity. It has to be an instance of AppCompatActivity if you want to use AppBar features. Also, the design library must be included in Gradle dependencies, like so: implementation 'com.android.support:design:26.1.0'
Please refer this link:-[https://medium.com/#tonia.tkachuk/appbarlayout-scroll-behavior-with-layout-scrollflags-2eec41b4366b][1]

JavaFX-8: Custom Layout and Layout Passes (layout pass/css pass): Where should I add child nodes?

I'm developing a custom table component for very large and very custom content. Therefore I decided not to go with TableView, but start from scratch (i.e. Control). I adopted the idea of the VirtualFlow to create and manage only the visible part of the table and reuse cells that have become invisible. However I needed virtual rows and columns.
My CustomVirtualFlow implements layoutChildren(). From the component's size and scrollbar positions I know which cells are visible. If necessary, I add cells to the VirtualFlow. I then update the content and css pseudo class states (selected, focused, ...).
This works almost fine ... currently, my only problem is that the css styles are sometimes lagging: newly created cells are shown with e.g. wrong backgrounds for a moment and then get correcteted with the next pulse.
My explanation for this is that JavaFX performs layout in two passes:
first a css pass and secondly the layout pass that calls layoutChildren().
The css of newly added children (during layoutChildren) is therefore not processes correctly.
I tried to call applyCss() directly, which helps, but seems to do too much because it takes a lot of time.
My question is:
How is the correct way to add nodes during layout, i.e. if the size of the component makes it neccessary to use further nodes?
If it is not during layoutChildren(), where else should I do it?

reuse and extend PresenterWidget GWTP?

i am new to GWT and GWTP and the question sounds stupid.. Can I make an abstract PresenterWidget or similiar?
Like in normal Java extending the "class" and reuse / extend the logic. But not only the class, the whole thing of View and Presenter. I try to explain my initial situation and maybe you have another idea.
The image hopefully helps to explain it. The "Main-Tab" and every other tab consists of a collection of views which have the same base structure and the same logic.
the base structure consists of
border around EVERYTHING
an image (the wwitch)
a title
a textarea
a PresenterWidget which is added to a contentSlot of the parent (the menu left)
and below the base are view specific components like buttons, text or any other widget. So a main part of the view with logic is repeading. If the switch is "toggled" the view is hidden (the textarea and any childs / view specific components) like the lowest view in the picture. Furthermore the PresenterWidget left changes the color.
The logic is working, but now I am searching a proper way to solve this without repeading code and the possibility to add child elements which are hidden as well by toggling the switch. Can I add to a PresenterWidget child widgets and define where there should be added? like: Even if this is possible, it feels a bit inconvenient.
Thanks in advance.
I just want to post the solution:
I have now a simple Composite (KPICommonView) for the switch, title and the description. It got another FlowPanel below the description, where the specific components will be added later. For this the Composite implements "HasWidgets" and overrides the "add(Widget w)"-method which is called by UiBinder if the Widget is added and has child elements.
<own:KPICommonView title="First Header" description="I am a happy description :)" anchorToken="{nameAnchors.getFirst}">
<g:Label>child component</g:Label>
</own:KPICommonView>
I am not sure if I do a PresenterWidget for every segment and every PresenterWidget has one of the KPICommonView added, or if I do one normal Presenter which adds more than one of the CommonViews.
The CommonView furhter creates the PresenterWidget for the menu item on the side. It gets the attributes from the constructor (anchorToken, title) and adds it to the slot (which happens ugly, because the View has hard coded the parent saved to call "addInSlot()". The repeading code for the switch is handled by the KPICommonView.

JavaFX 2 change layout dynamically at runtime?

Swing had LayoutManager's separate from the containers. So far as I can tell, JavaFX doesn't do that.
I have a complex structure of nodes that I want the user to be able to toggle between several different layout approaches. Something equivalent to the user specifying flow and all containers are converted to the equivalent of FlowPanes. Then they could choose vertical and everything is laid out vertically.
Is there a way to do this other than swapping out the nodes/recreating the whole structure?
I should note: the hierarchy changes at runtime and it is deeply nested.
I mention Swing because this is straightforward to do in Swing by maintaining a list of all containers in the entire hierarchy, and with a simple loop (or tree traversal without the list) setting a new LayoutManager on them. JavaFX doesn't seem to have this possibility because the layout behavior appears to be internal to the nodes.
Isn't something like this working ?
AnchorPane main=new AnchorPane();
AnchorPane sub1=new AnchorPane();
sub1.getChildren().add(btn);
main.getChildren().add(sub1);
When you want to switch the layout
AnchorPane sub2=new AnchorPane();
main.getChildren().remove(sub1);
main.getChildren().add(sub2);
Edit
I guess I missed how you are doing layouts. This is how I envisioned it.
Definitions to Various Components
MainLayout
-> CustomLayout 1
-> References to various components. ( Essentially you are not creating all the components for every layout, rather you are referring to them in each layout )
-> CustomLayout 2
-> References to various components. ( More or less a different arrangement of the same components, adds some component references and removes some )
-> CustomLayout 3
-> References to various components.
Making a bold statement, but if there were a tool in JavaFX, how would it do this automatically ? Each template needs to know where it should render a particular component and arguably the easiest way to do this is just create a new template that arranges the components in a different layout and swap the template when user wants to see a different layout.
This is not easy to do in Swing. You would still need to set all the layout constraints on the individual components again, unless your layout is very straightforward.
I don't see how there is much difference in this between swing and javaFX. In JavaFX you would need to add the same controls to a different container (VBox, HBox etc.) but you still don't need to recreate the controls every time. It is a little awkward to find the containers in the middle of the node hierarchy but I'm sure there is some kind of elegant recursive solution :)

how to set lwuit textarea scrolling false

I want to add large string content to a container dynamically.
There are 60 different contents(strings) to be displayed in this container.
To add the string to container, I am adding a TextArea(empty border with 100% transparency).
The problem is that TextArea offers scroll and I do not want it to scroll. Instead I want to grow(increase height) according to content. I am unable to achieve this.
Can you help me out with this?
Or can I use any other component for the purpose?
I am using LWUIT with J2ME.
You can derive text area and return false for isScrollableY() although it should generally work seamlessly even if you don't do that (since your parent layout is scrollable). Is it possible you changed the text area and don't revalidate the parent form on the EDT?
There are problems with text area layout when it is modified by a separate thread (race condition with the layout code).
First put the TextArea.setSingleLineTextArea(false) , and grow by content true.

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