How to make nodes in a chart focus traversable? - java

I'm on javafx-8 and java8, trying to make an interactive chart.
So far I've implemented all the mouse actions (highlight on mouse over, drag&drop to change values etc), but I'm not able to implement any keyboard interactions (basically changing its value with arrow keys) because the nodes (i.e. pic below) in a chart cannot gain focus.
When I try to set the focusTraversable property is fails with exception
java.lang.RuntimeException: StackPane.focusTraversable : A bound value cannot be set.
I have tried setting it on the chart but it doesn't get propagated to the data points (nodes). Can someone please point me the right way? thanks!

The binding of the symbol's focusTraversal is used in accessibility - the snippet from LineChart.createSymbol(..):
symbol.focusTraversableProperty().bind(Platform.accessibilityActiveProperty());
As long as you can live without following accessibility constraints, you might get away (untested for side-effects!) by simply unbinding before setting it to true, something like:
Node node = data.getNode();
node.focusTraversableProperty().unbind();
node.setFocusTraversable(true);

Related

JavaFX elements aligning right before animating

I'm developing a small GUI using JavaFX for an assignment. Having never used JavaFX before, most of what I've used or learned I've research myself. Most of my application runs smoothly, animations included.
I have a small user input section:
I'm trying to allow it to swipe left prior to loading the next scene, to give the user the impression of sequence. I achieved this using a ParallelTransition populated by TranslationTransitions in which I load all of these Nodes.
However, just slightly before it animates, it appears to align everything right.
I have a feeling this is something to do with the container (AnchorPane) in which I'm placing these objects, or some undefined attribute which I'm not setting. As I'm learning this all on the fly, it's a bit difficult to narrow down. Can anyone give me an idea as to what is causing this and how I can retain the alignment? Each Node moves in the following way:
translateTransition.setFromX(node.getLayoutX());
translateTransition.setToX(node.getLayoutX()-500.00);
If I've left out any pertinent information, please let me know!
So, my issue turned out to be the way I'm laying out my objects. Placing them in an arbitrary AnchorPane with only specific attributes to locate those items means that, upon animation, it will group those objects and animate them accordingly. It was the incorrect way to layout those nodes.
Instead, I've placed them in a VBox which has two advantages.
I can align the contents of that VBox centre, so I need not specify the exact layout attributes of the elements.
I can animate using the single VBox, as opposed to the all the elements in a ParallelTransition. As a result, a single TranslateTransition on the VBox node will suffice!

Tracking data offset of data in a table to retrieve the previous/next subset on table scroll

I am writing a browser based application using GWT and making use of websql (yes, I know it is deprecated). I have created a custom table widget (based on FlexTable) and enabled it to scroll with the help of some CSS trickery. What I am striving to achieve (without much success) is that when the user scrolls to the start/end of the current data in the table, an event is fired and the next subset of X rows is returned from the websql DB and replaces the data currently in the table. In order for this to work, I need to keep track of the data offset in the table widget so that I can pass this to the query and use the limit and offset functions of SQL to return the required data. However, I just cannot seem to get the logic right to implement the data offset tracker within the widget. Another complication is that I need the table to be able to scroll 'into the past' (so to speak), so that it can retrieve data from before the initial start point when the table loads.
I have been at this for a number of days now and just cannot seem to get it right. So I was wondering/hoping that someone might be able to point me in the right direction (PLEASE!).
Thanks in advance
Tim
I am not sure why this is causing a problem.
int page = 0;
// when you hit the bottom
page++;
loadData(page);
// when you hit the top
if (page > 0) {
page--;
loadData(page);
}
Tim I think it is not a good idea controlling the scroll with CSS trickery.
I have done something similar soon and controlling all the logic (pagination, scroll positions,...).
What I suggest to use is a gwt's scrollPanel, a HasData widget (like a cellList) your custom AbstractCell (class which is rendered for each row of your list) and asyncDataProvider ( which gives you the onRangeChange handler for asking to your server when the range data display has changed).
You can force/fire that event when in scrollPanel.addScrollHandler detects you are arriving to the end.
If you want to see all of this in action have a look into (click on source code): http://gwt.googleusercontent.com/samples/Showcase/Showcase.html#!CwCellList
EDIT [according comment below]:
A. If you want to override the data (in the example is X+X+X...) with the new retrieved just maintain always the same range of data displayed [display.setVisibleRange(0, newPageSize);], and start from 0 when you render the new data (on your RangeChange listener).
B. If you need to have control over up and down scrolls instead of taking advantage of the used events internally on the cellList (basically onRangeChange), you can create your custom events and fire them (this option could be easier for your colleagues for understanding everything). And do not worry about controlling up and down scrolls, inside the ShowMorePagerPanel.java you can see a simple example of knowing up and down controls.
Anyway, I did not explain more detailed because I did not see you very convinced to use CellList approach (and I was using my tablet :D ).
If you change your mind, just let me know and I write for you a proper example step by step (this part could be tricky, so if you are lost it is normal ;) ).

StyledText nullpointer

Im working with SWT StyledText to display data to the user in one part of the window. In another part I have a graph, over which I slide my mouse pointer. As I slide my mouse over a point in the graph, it highlights the corresponding entry in the StyledText Area.
I want my textArea to automatically scroll to the newest change, so I am using .setTopIndex().
To determine the index I need to be able to look at which entries in the textArea changed from not highlighted to highligted, I use the following (to check if my styleRange changed):
styledText.getStyleRangeAtOffset(offset)
So far my program functions correctly. My next check is:
styledText.getStyleRangeAtOffset(offset).isUnstyled
or
styledText.getStyleRangeAtOffset(offset).foreground
or something like that. Here enters the problem. When I call any of these I get a nullPointerException.
Thank you for all the pointers :) after some debugging I discovered that the unedited styleRange is null. That explains the nullPointer I kept on receiving

Best way to stop tooltips disappearing in JFreeChart

I noticed that if I hover over my graphs it shows the tooltips like expected, but after a certain time they disappear. Now I managed to get around this problem by using setDismissDelay of the ChartPanel and setting it to a very high number, but this doesn't look like best practise.
Is there a better way to do this, maybe disable the method that hides the tooltip?
Instead of altering the tooltip parameters, add a ChartMouseListener that updates an adjacent component in its chartMouseMoved() handler. You can display the same data as the tooltip generator, and it won't change until the mouse moves. There's a related example here.

Formatting JEditorPane's cursor, tooltips, links

Right now, I'm using Java Swing to create a JEditorPane primarily for its ability to have hyperlinks. I've successfully been able to display links and have them execute behavior upon a click, but I'm running into a few problems with formatting.
How can I set the cursor so that it normally is an arrow, but changes to a text cursor when hovering over text? (In essence, the behavior a cursor has within a web browser). I tried
EditorPane.setCursor(new Cursor(Cursor.TEXT_CURSOR))
but that made it a text cursor everywhere, even when not hovering over text. Right now, hovering over a link shows a pointer hand; I'd like to maintain that functionality as well.
What is the best way to show tooltips or mouseover text when hovering over a link? I tried modifying the title attribute of the link but nothing showed up.
I was trying to implement links to skip down to a subsection of the page, much like http://en.wikipedia.org/wiki/Xkcd#History would take you directly to the History subsection of Wikipedia's xkcd page. How can I do this?
An answer to any of these would be great (and multiple would be awesome xP). Thanks a lot for your help!
As you said one can simply give answers to a single point as well, let me try one by one, here is the answer for your last Point 3
Just provide an id to your tag like this
<h1><a id = "top"></a>First Line</h1>
Now somewhere in the bottom of your page write this :
<p>Return to TOP</p>
Clicking this link, you will reach the above area of the PAGE.
Points 1 & 2 may be addressed using the approach mentioned here. In particular, the view/model conversion methods will let you condition setCursor() and getToolTipText(), respectively.
You can get source from here http://java-sl.com/JEditorPaneStructureTool.html
It shows how to obtain text view bounds. First you get caret position for current mouse poiunter using viewToModel() method. Then go down the Views tree achieving leaf view and calcualte it's bounds. See this http://java-sl.com/tip_view_rectangle.html
If your mouse pointer in the view's rectangle then your mouse over text.
You can check whether the text in caret position is link and show your tooltip.
Use this http://java-sl.com/tip_links_in_editable.html to see how to detect whether mouse is over link.
Point 3.rd is answered by #nIcE cOw

Categories

Resources