Get the number of rows in a JavaFX GridPane?

Question

I initialized a GridPane through SceneBuilder and inside the controller I want to conditionally add a row to the GridPane. I do not want to store an int for how many rows I initialized, I want to be able to get the number of rows from the GridPane object. Is that possible?

Occupational

Answer 1

Hej j will, try this method:

private int getRowCount(GridPane pane) {
        int numRows = pane.getRowConstraints().size();
        for (int i = 0; i < pane.getChildren().size(); i++) {
            Node child = pane.getChildren().get(i);
            if (child.isManaged()) {
                Integer rowIndex = GridPane.getRowIndex(child);
                if(rowIndex != null){
                    numRows = Math.max(numRows,rowIndex+1);
                }
            }
        }
        return numRows;
    }

This worked for me.

Patrick

Performance

Isn't rowIndex and rowEnd same numbers? Both are obtained with GridPane.getRowIndex(child). – Summons

Yeah this doesn't work when I prorammatically add rows to a gridpane it still shows the initial row count, so it has issues – Delrio

I could have a valid GridPane with a non-empty set of rows, then call getRowConstraints() which is a list, call clear() to clear this list to remove all constraints and then when I call your getRowCount() get a return value of 0 even though the grid still has the same number of rows. – Divertissement

Answer 2

In my case I used Java Reflections ( GridPane.java has private method getNumberOfRows() ):

Method method = gridPane.getClass().getDeclaredMethod("getNumberOfRows");
method.setAccessible(true);
Integer rows = (Integer) method.invoke(gridPane);

Endodontics

this works after I have added rows in code otherwise all I get is the initial allocation, which is dumb, poor form from the designers of the GridPane class – Delrio

Answer 3

With java 9, you can do this:

myGridPane.getRowCount();

Atony

I believe this returns the row index of the element with the largest row index, so if you have gaps between rows, this doesn't return the number of rows. – Harquebus

Answer 4

This works for me

GridPane.getRowConstraints().size()

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