Develop Reference

Is there any other way to implement setOnMouseClicked on JavaFX

I had to create a matrix in javaFX. I created it without any problem with GridPane. The next thing is to create like "buttons" on the right side of the matrix, these buttons will move +1 element of the matrix to the right. Like this:
110 <-
101 <- //ie: I clicked this button
100 <-
The result:
110 <-
110 <-
100 <-
The way I handle this bit-shifting-moving was with circular linked list. I don't have any problem with that I think you can ommit that part. I use this method:
private void moveRowRight(int index){
//recives a index row and moves +1 the elements of that row in the matrix.
}
cells is the matrix
The problem is that, first the matrix can be modified by the user input i.e. 5x5 6x6 7x7, so the number of buttons will also change. I tried using a BorderPane(center: gridpane(matrix), right: VBox()) and this is the part of the code how I added some HBox inside the Vbox (right part of the border pane) and using the setOnMouseClicked.
private void loadButtonsRight(){
for(int i = 0; i < cells[0].length ; i++){
HBox newBox = new HBox();
newBox.getChildren().add(new Text("MOVE"));
newBox.prefHeight(50);
newBox.prefWidth(50);
newBox.setOnMouseClicked(e -> {
moveRowRight(i);
});
VBRightButtons.getChildren().add(newBox); //where I add the HBox to the VBox (right part of the Border Pane)
}
}
}
But then there's this problem.
Local variables referenced from lambda expression must be final or effectively final
It seems that I cannot implement lambda with a value that will change. Is there any way to help me to put "buttons" that depends of the matrix size and that uses the method I've created?

The message tells you all you need to know to fix the problem:
Local variables referenced from lambda expression must be final or effectively final
Assign your changing variable to a final constant and use the constant value in the lambda instead of the variable:
final int idx = i;
newBox.setOnMouseClicked(e ->
moveRowRight(idx);
);
If you wish to understand this more, see the baeldung tutorial
https://www.baeldung.com/java-lambda-effectively-final-local-variables

Vbox not filling up all of the available space in a gridpane

I am currently developing a messenger in javafx. my general layout is a gridpane with a customized Vbox containing a ListView and a Textfield. The problem is that as you can see below there is a big emty area beneath the textfield. I already tried setting the rowspan to 2, which didn't work.
The important Code:
Main:
chatBox = new ChatBox();
gridPane.add(chatBox, 1, 0, 1, 2);
ChatBox(extends Vbox):
private static ListView<Message> messages;
private TextField inputField;
public ChatBox() {
inputField = new TextField();
messages = new ListView<>();
init();
getChildren().addAll(messages, inputField);
}

Try adding this in the ChatBox class:
VBox.setVgrow(messages, Priority.ALWAYS);
And add this in the main class:
GridPane.setVgrow(chatBox, Priority.ALWAYS);

You need to set the vgrow using RowConstraints. Assuming your first row contains the ListView that is supposed to take all the available space:
RowConstraints constraints = new RowConstraints();
constraints.setVgrow(Priority.ALWAYS);
gridPane.getRowConstraints().addAll(constraints, new RowConstraints());

In order to force the list view to take all the height available in its parent, you can use the following method:
messages.setMaxHeight(Double.MAX_VALUE);
If the problem comes from the VBox, its maxHeight can also be modified with the same method.

Replace a node at (row,col) in a JavaFX GridPane

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.

JavaFX How to add Wrapped Text to GridPane

When I was append some text dynamically to the TextArea it was wrapped correctly as follow:
But due to requirement changed I have to add some image as bullet for (in front of the) each text. Then I used GridPane to add those text with images as follow:
Code used to add components to GridPane:
// Set the GridPane empty
gridPane.getChildren().removeAll();
// Add image with each text
int index = 0;
for(String des : descriptionsList) {
HBox btnHb = new HBox();
ImageView passed = new ImageView();
passed.setImage(new Image(getClass().getResourceAsStream(GuiConstant.Image.IMAGE_PASSED)));
btnHb.getChildren().add(passed);
Text text = new Text(des);
btnHb.getChildren().add(text);
gridPane.addRow(index, btnHb);
index++;
}
Now (with GridPane) added Texts are not wrapped properly. How can I fix this issue. Thanks.

You need to set the wrappingWidth on the Text instances to be relative to the width of the GridPane. You may want to do that indirectly via the HBox instances:
btnHub.prefWidthProperty().bind(gridPane.widthProperty();
text.wrappingWidthProperty().bind(btnHub.widthProperty().subtract(passed.widthProperty().subtract(10));
I didn't actually try these changes, but they (or something very similar) should do the trick.

JavaFX Grid Pane and content size

I've been trying to get a GridPane's content to behave regarding auto-size but I'm relatively new to JavaFX, so I've not had any success. Basically, each column is what appears to me to be a completely random size, and I have no idea how to make them grow correctly. If I try to set column constraints, the content sometimes disappears completely, sometimes it's just sized completely arbitrarily. Trying to bind preferred width to anything else also fails to work. I'm sure the error is mine, though. Here's my code (the contentHolder is a ScrollPane with vGrow set to ALWAYS):
int row = 1;
GridPane gridPane = new GridPane();
for (List<IndexObject> stepList : search) {
Label itemLabel = new Label();
itemLabel.setText(String.valueOf(row));
TreeItem<String> treeRoot = new TreeItem<>(stepList.get(0).getPath());
for (int line = 1; line < stepList.size(); line++) {
treeRoot.getChildren().add(new TreeItem<>(stepList.get(line).getPath()));
}
TreeView treeView = new TreeView();
treeView.setShowRoot(true);
treeView.setRoot(treeRoot);
treeRoot.setExpanded(true);
IndexObject lastObject = stepList.get(stepList.size() - 1);
TextArea output = new TextArea();
output.setText(lastObject.prettyPrint());
gridPane.addRow(row, itemLabel, treeView, output);
row++;
}
contentHolder.setContent(gridPane);
Everything up to the contentHolder is defined in fxml. Here's what it looks like. No entry has anywhere near the height that is automatically assigned, but all the widths are too small. What am I missing?

The answer is that the scroll pane does not automatically resize until you make it:
<ScrollPane VBox.vgrow="ALWAYS" fitToWidth="true">
at which point everything works as expected.