I've implemented drag and drop in my JTree and it works, but I find this to be a bit confusing. In the picture, I'm showing how the drop location between item4 and item5 can vary depending on how far down between the nodes you are. I'm guessing this is because the row boundaries for item4 and item5 meet in the middle between them, and depending on which side you are on, you are actually in a different row.
From a user perspective, I think this is not natural. I would think that if I dropped above a node, the drop would occur above it. If I dropped below the node, the drop would occur below it. Is there a way to configure that sort of behavior?
EDIT: Adding code to show how to get drop location
DropLocation dropLoc = support.getDropLocation();
Point dropPoint = dropLoc.getDropPoint();
tree.getTree().getPathForLocation(dropPoint.x, dropPoint.y);
Note that support is a TransferSupport object
EDIT 2: I seemed to have solved this problem by checking if the drop point is above or below the halfway point of the node. Then I can tell if the drop was above or below which node.
You have sort out of the answer, but since i have sort out the code, thinking still worth to post it.
public void dragOver(DropTargetDragEvent dtde)
{
Point dropPoint = dtde.getLocation();
TreePath path = tree.getPathForLocation(dropPoint.x, dropPoint.y);
Rectangle pathBounds = tree.getPathBounds(path);
Rectangle topHalf = new Rectangle(pathBounds.x, pathBounds.y, pathBounds.width, pathBounds.height / 2);
if (topHalf.contains(dropPoint))
{
System.out.println("top half");
}
else
{
System.out.println("bottom half");
}
}
Related
My layout issue
I have a little issue with ListView and I'm not sure if it's because of some knowledge I missing or if my approach is flawed. Have to admit I'm not yet clear with how JavaFX handle the layout in the many possible cases.
The above screenshot shows the result I get twice with the exact same code, except that on the second one an invisible shape I use for coherent layout is made visible for debug.
The various classes involved by the CellFactory extend Group, I tried with some other Parent without much success so far.
How to reproduce
Rather than sharing my StarShape, StarRow and some other misc classes (I'd be happy to if requested) I wrote a sample reproducing the issue. The class extends Application and overrides the start(...) method as such:
#Override
public void start(Stage primaryStage) throws Exception {
final StackPane root = new StackPane();
final Scene scene = new Scene(root, 400, 600);
final ListView<Boolean> listView = new ListView<>();
listView.setCellFactory(this::cellFactory);
for (int i = 0; i < 5 ; i++) {
listView.getItems().add(true);
listView.getItems().add(false);
}
root.getChildren().add(listView);
primaryStage.setScene(scene);
primaryStage.setTitle("ListView trims the invisible");
primaryStage.show();
}
where this::cellFactory is
private ListCell<Boolean> cellFactory(ListView<Boolean> listView) {
return new ListCell<Boolean>() {
#Override
protected void updateItem(Boolean item, boolean empty) {
super.updateItem(item, empty);
if (empty || item == null) {
setText(null);
} else {
final Rectangle tabShape = new Rectangle();
tabShape.setHeight(20);
tabShape.setWidth(40);
tabShape.setVisible(item);
final Label label = new Label(item.toString());
label.setLayoutX(40);
final Group cellRoot = new Group();
cellRoot.getChildren().add(tabShape);
cellRoot.getChildren().add(label);
setGraphic(cellRoot);
}
}
};
}
The above will display a ListView<Boolean> with black shapes in front of true items (because of the tabShape.setVisible(item); bit). The false items are looking like regular Label objects as if the invisible shape in their Group wasn't there (but it is).
Closing comments
Debugging this, it turns out groups with the invisible shapes are given negative layoutX property values. Thus Label controls aren't aligned as I'd like them to be. It doesn't happen when I call setLayoutX and setLayoutY outside of a ListView (the invisible shapes do force offsets), but it's probably not the only place where it would happen.
What's happening and how to avoid it? Alternatively, as I'm guessing I'm approaching this wrong, what'd be the right way? In other words, what is the question I should be asking instead of this?
Taking from #dlatikay's comment, instead of setting the placeholder items to invisible, you can render them transparent by setting their opacity to 0.0.
Applied to the MCVE from your question, this would be done by replacing:
tabShape.setVisible(item);
with:
tabShape.setOpacity(item ? 1.0 : 0.0);
In terms of user experience, you could take this one step further. Instead of setting the "inactive" stars to fully transparent, you could set them to be near-transparent, as in this mockup (with opacity set to 0.1):
The benefits that I see are:
It indicates not only the rating of an item in the list, but also the maximum rating.
It avoids awkward empty spaces for list items with zero stars.
I'm guessing I'm approaching this wrong
No, you're not. As with all layouts, there's often multiple ways to approach the same problem. Your approach is actually correct, and you're very close to a working solution.
You can achieve what you're after with a mere 1 line change. That is, changing the Group to an HBox.
An HBox ensures that elements are ordered horizontally, one after another. They also allow invisible elements to still take up space.
I also commented out one line: label.setLayoutX(40). I did this because HBox will not respect this setting, and actually you don't need it to. It will automatically shift the elements horizontally by as much is required.
#Override
protected void updateItem(Boolean item, boolean empty) {
super.updateItem(item, empty);
if (empty || item == null) {
setText(null);
}
else {
final Rectangle tabShape = new Rectangle();
tabShape.setHeight(20);
tabShape.setWidth(40);
tabShape.setVisible(item);
final Label label = new Label(item.toString());
//label.setLayoutX(40);
final HBox cellRoot = new HBox();
cellRoot.getChildren().add(tabShape);
cellRoot.getChildren().add(label);
setGraphic(cellRoot);
}
}
When I make those changes, your layout will render like so:
Important: Your example and your screenshots are slightly different. You may want to use a VBox for your star example (V for 'vertical', H for 'horizontal').
I have a problem that I have been unable to solve in a way that I am very happy with.
I have a view that I am dragging and dropping into a list. That list is created using a recyclerView. The drag object works fine, and the recyclerView's items can all receive the events no problem. Now I want to make the list scroll as the user drags their finger close to the top or bottom of the list. My first step was to add a dragEvent listener to the recyclerView, and attempt to start scrolling each time I got a location near the top or bottom edge. So, my DragEvent.Location case looks something like this:
case DragEvent.ACTION_DRAG_LOCATION: {
removeDragScrollCallBack();
float y = event.getY();
final int scrollAreaHeight = v.getHeight()/4;
final int delayMills = 16;
int scrollAmount = 0;
if (y > v.getHeight() - scrollAreaHeight) {
scrollAmount = 10;
} else if (y < scrollAreaHeight) {
scrollAmount = -10;
}
if (Math.abs(scrollAmount) > 0) {
final int finalScrollAmount = scrollAmount;
dragScrollRunnable = new Runnable() {
#Override
public void run() {
if (canScrollVertically(finalScrollAmount)) {
scrollBy(0, finalScrollAmount);
if (dragScrollHandler != null && dragScrollRunnable != null) {
dragScrollHandler.postDelayed(this, delayMills);
}
}
}
};
dragScrollRunnable.run();
}
return true;
}
It kinda works. Things scroll in the right direction. It seems to sputter a bit though, and generally not scroll very smoothly. Additionally, the drag and drop drop event sometimes doesn't make it to the children while the recycler view is still scrolling.
So, I went to the google example of doing a similar thing in a using a list view - link. I modified the code they used for their list view and tried to handle my recyclerView in a similar manner. This had even poorer results for me.
I have tried various other alterations of these techniques, and swapped to using the smoothScroll function instead of the standard scroll function, but I'm not too happy with any of the results.
Does anyone have a good solution for how to handle this?
Update: I now believe that many of my problems with this functionality are due to the drag listener being fairly unreliable. At sometimes the recycler fails to get events when it's children are receiving events.
Turns out the drag listener on a view is not terribly reliable. At random times as I moved my finger around the screen, the drag listener wouldn't recieve all of the events. I believe the reason for this was the way that the children of the recyclerView were also recieving the on drag callbacks. The solution was to do what I had tried originally, but through a listener on the fragment itself. Now when I get an event, I check the coordinates to see what view it is in, and then convert it to local coordinates for that view. Then I can determine exactly how I need to handle it.
I'm trying to stop the tree from collapsing or expanding when the user double clicks a column on a tree. It should only be allowed if the user clicks on the first column.
See, if a user double clicks the checkbox on node2 world1, the tree expands or collapses. I don't want that to happen. My tree needs SWT.FULL_SELECTION to detect the clicks on each of the columns, so that's not the way to go.
My listener looks like this
tree.addTreeListener(new TreeListener() {
#Override
public void treeExpanded(TreeEvent e) {
TreeItem parent = (TreeItem) e.item;
Point p = new Point (e.x, e.y);
int column = CheckboxClickListener.getColumn(p,parent);
if (column > 0) {
e.doit = false;
}
}
#Override
public void treeCollapsed(TreeEvent e) {
TreeItem parent = (TreeItem) e.item;
Point p = new Point (e.x, e.y);
int column = CheckboxClickListener.getColumn(p,parent);
if (column != 0) {
e.doit = false;
}
}
});
Problem is, the mouse event that generated the click is not the same as the TreeEvent that expands the tree. Thus, the e.x and e.y are both zero, making my Point detection useless. Listening to the mouse event and maintaining the last x and y to check here in the TreeExpand event seems bug-prone since the user may also expand the tree using the keyboard (thus the x and y may not reflect the user action). I also considered adding a time constraint to check that but seems like a bad way to handle the issue.
How can I detect which mouse event triggered the expand event?
PS: e.doit=false does nothing, even outside the if condition, so help with stopping the tree from expanding/collapsing would be appreciated as well :)
Thank you!
I found someone saying this is a bug at this link http://www.eclipse.org/forums/index.php/t/257325/
The following code stops the tree from expanding on doubleclick but I'm not sure why or what are the side effects.
tree.addListener (SWT.MeasureItem, new Listener(){
#Override
public void handleEvent(Event event) {}
});
This stops the expanding when doubleclicking ANY column. Clicking on the small arrow at the left of the TreeItem still expands the tree (as it should).
I am making a grid-style game/simulation based on bugs "sensing" and eating food. I am using a gridPane (called worldGrid) of labels to show the grid of bugs and food. This is obviously going to be constantly updated when a bug moves cells towards food etc.
I currently have a function updateGrid(int col, int row, String cellContent) which I want to replace the label at [row,col] with a label that has the new text in cellContent.
I have the follow which works
worldGrid.add(new Label(cellContent), row,col);
however im worried that that is just adding a label on top of the current label and obviously over 100 iterations of the simulation thats not ideal.
I have tried this before adding the label:
worldGrid.getChildren().remove(row,col);
However I then get an IllegalArgumentException when trying to do the add line.
Any ideas on how to do this? Or even better, any ideas on how best to show a constantly changing grid that will eventually use sprites instead of text?
The col/row provided by grid.add(node, col, row) (ATTENTION first comes col!) is only a layout constraint. This does not provide any means to access columns or rows like slots in a 2-dimensional array. So to replace a node, you have to know its object itself, e.g. remember them in a separate array.
Then you are able to call getChildren().remove(object)... e.g.:
GridPane grid = new GridPane();
Label first = new Label("first");
Label second = new Label("second");
grid.add(first, 1, 1);
grid.add(second, 2, 2);
second.setOnMouseClicked(e -> {
grid.getChildren().remove(second);
grid.add(new Label("last"), 2, 2);
});
box.getChildren().addAll(grid);
I agree with Jens-Peter but I would add that you can use GridPane's getColumnIndex and getRowIndex to obtain a particular node's location.
For example ( this is in a component which extends GridPane ):
// set the appropriate label
for (Node node : getChildren()) {
if (node instanceof Label
&& getColumnIndex(node) == column
&& getRowIndex(node) == row) {
((Label)node).setTooltip(new Tooltip(tooltip));
}
}
in other words, go through all the nodes in the GridPane and check for a match of the conditions you want, in this case row and column.
You called getChildren().remove() method directly will cause the gridpane to go out of sync with the constraints. When you add, it also setup the constraint for the node. Add clearConstraints() method.
So, my issue is this: I'm attempting to define a custom set of nodes for a Javafx XYChart LineChart, where each node corresponds to a point that was plotted directly from the datasets. After looking around a little bit, Jewlesea actually had a solution at one point about how to add dynamic labels to nodes on a linechart graph that gave me enough of a push in the right direction to create black symbols (they are dots at the moment, but they can be many different things). Now I have a requirement that requires me to change ONE of the nodes on the XY chart into an 'X'. this could be either through loading an image in place of the 'node', or through physically manipulating the 'shape' parameter in .css.
The problem begins when I try to add this property dynamically, since which node has the 'x' will always be changing. Here are the things I've tried, and they all end up with no results whatsoever, regardless of the property used.
private XYChart.Data datum( Double x, Double y )
{
final XYChart.Data data = new XYChart.Data(x, y);
data.setNode(
new HoveredThresholdNode(x, y));
//data.getNode().setStyle("-fx-background-image: url(\"redX.png\");");
data.getNode().styleProperty().bind(
new SimpleStringProperty("-fx-background-color: #0181e2;")
.concat("-fx-font-size: 20px;")
.concat("-fx-background-radius: 0;")
.concat("-fx-background-insets: 0;")
.concat("-fx-shape: \"M2,0 L5,4 L8,0 L10,0 L10,2 L6,5 L10,8 L10,10 L8,10 L5,6 L2,10 L0,10 L0,8 L4,5 L0,2 L0,0 Z\";")
);
data.getNode().toFront();
return data;
}
So in the above, you can see that this is adding a property through the use of the 'bind' function after the dataNode has already been created. Also note above, I tried doing it through the 'setStyle' interface at this level to give it a background image, with no success. Also, no errors are being thrown, no 'invalid css' or anything of the sort, just simply no display on the graph at all when done this way.
now, in the HoveredThresholdNode (Again a big thanks to Jewelsea for being a master of Javafx and putting this bit of code online, it's where 90% of this class came from.) I tried essentially the same thing, at a different level. (actually being IN the node creation class, as opposed to a layer above it).
class HoveredThresholdNode extends StackPane {
/**
*
* #param x the x value of our node (this gets passed around a bunch)
* #param y the y value of our node (also gets passed around a bunch)
*/
HoveredThresholdNode(Double x, Double y) {
//The preferred size of each node of the graph
//getStylesheets().add(getClass().getResource("style/XYChart.css").toExternalForm());
//getStyleClass().add("xyChart-Node");
//setOpacity(.8);
styleProperty().bind(
new SimpleStringProperty("-fx-background-color: #0181e2;")
.concat("-fx-font-size: 20px;")
.concat("-fx-background-radius: 0;")
.concat("-fx-background-insets: 0;")
.concat("-fx-shape: \"M2,0 L5,4 L8,0 L10,0 L10,2 L6,5 L10,8 L10,10 L8,10 L5,6 L2,10 L0,10 L0,8 L4,5 L0,2 L0,0 Z\";")
);
//this label is the 'tooltip' label for the graph.
final Label label = createDataThresholdLabel(x, y);
final double Myx = x;
final double Myy = y;
setOnMouseEntered(new EventHandler<MouseEvent>() {
#Override public void handle(MouseEvent mouseEvent) {
if (Myx == 0) {
label.setTextFill(Color.DARKGRAY);
} else if (Myx > 0) {
label.setTextFill(Color.SPRINGGREEN);
} else {
label.setTextFill(Color.FIREBRICK);
}
label.setText("Current position: " + Myx + " , " + Myy);
//setCursor(Cursor.NONE);
toFront();
}
});
setOnMouseExited(new EventHandler<MouseEvent>() {
#Override public void handle(MouseEvent mouseEvent) {
//getChildren().clear();
//setCursor(Cursor.CROSSHAIR);
}
});
}
Now note, I also tried the setStyle(java.lang.String) method, with all of the same type of CSS, with no success. I have NO idea why this isn't styling dynamically. It's almost as if the custom nodes are simply ignoring all new .css that I define at runtime?
Any help would be greatly appreciated, please don't be shy if you need more details or explanation on any points.
So, I did finally find a good workaround to solve my problem, although not in the way I thought it would happen. The main problem I was having, was that I was extending from stackPane to create my node, which only had a very small number of graphical display options available to it, and by switching the 'prefSize()' property, I was simply changing the size of that stackPane, and then filling in the background area of that stack pane black, giving it a very deceptive shape-look to it.
So rather than use a stack pane, whenever I reached the node that I needed to place the red 'X' on, I simply called a different Datum method that returned a datum with an ImageView Attached, like so:
private XYChart.Data CoLDatum(Double x, Double y){
final XYChart.Data data = new XYChart.Data(x, y);
ImageView myImage = new ImageView(new Image(getClass().getResource("style/redX.png").toExternalForm()));
data.setNode(myImage);
data.getNode().setOnMouseEntered(new EventHandler<MouseEvent>() {
#Override public void handle(MouseEvent mouseEvent) {
main_label.setText("Some Text.");
}
});
data.getNode().setOnMouseExited(new EventHandler<MouseEvent>(){
#Override public void handle(MouseEvent mouseEvent) {
main_label.setText("");
}
});
return data;
}
and since ImageView is an implementing class of Node, this worked out just fine, and allowed me to load up an image for that one single node in the graph, while still maintaining a listener to give custom text to our information label when the red 'x' was hovered over with a mouse. Sometimes, it's the simple solutions that slip right past you.
I imagine that, had I employed stackPane properties properly with the setStyle(java.lang.String) method, they would have absolutely shown up, and I was just butchering the nature of a stack pane. Interesting.
Hopefully this helps somebody else stuck with similar problems!