Clean gridPane in JavaFX and maintain the Grid line

Question

I'm trying to make a simple game (it is a school work) in JavaFX and I am trying to clear the panel with the board, and then just repaint it. I have tried a lot of methods, and this one is the only one I found that removes all the pieces of the board (visually) without creating a visual bug that shows a piece that has already been deleted but is still shown.

So I declare the gridPane like this:

private GridPane gridPecas;

@Override
public void start(Stage primaryStage)
{
    gridPecas = new GridPane();
    gridPecas.setGridLinesVisible(true);

    paintBoard();

    // rest of the code to create and paint the Stage
 }

 private void paintBoard()
 {
    gridPecas.getChildren().clear();
    // Code to fill the board with ImageView and Images of the pieces
 }

The problem with this method, is that when the "gridPecas.getChildren().clear();" is called I just loose the grid lines from the GridPanel.

How can I solve this problem?

Laquitalar

Answer 1

setGridLinesVisible(boolean) is for debug only:

http://docs.oracle.com/javafx/2/api/javafx/scene/layout/GridPane.html#setGridLinesVisible(boolean)

You can't even change the gridLines color for exemple.

So you should find another way to make your gridlines, and then call

yourPane.getChildren().clear();

because it's better than gridPecas.getChildren().removeAll(pecasFX[i][j]);

Elexa

Answer 2

A way to clear the GridPane and maintain the Gridlines is as follow :

    Node node = grid.getChildren().get(0);
    grid.getChildren().clear();
    grid.getChildren().add(0,node);

the first Node* in the GridPane (*if you set the GridLinesVisible before adding elements in the grid?) contains the Gridlines (and maybe other things).

So you just need to keep this Node before the clear & re-add it after

Downward

Answer 3

a one-liner: grid.getChildren().retainAll(grid.getChildren().get(0));

Oxtail

Answer 4

Valid clear GridPane and restore mainrtain grid lines:

gridPane.setGridLinesVisible(false);
gridPane.getColumnConstraints().clear();
gridPane.getRowConstraints().clear();
gridPane.getChildren().clear();
gridPane.setGridLinesVisible(true);

Shipper

Answer 5

Hmm my suggestion is not to clear all children at all. Always leave the imageViews and just replace the images they show. To "clear" the board put an "empty" image.

Succeed

Thank you for your answers, but I've just found the perfect solution xD Instead of doing "gridPecas.getChildren().clear();" I just do this in the for cycle : "gridPecas.getChildren().removeAll(pecasFX[i][j]);" So that when reading the piece it deletes it from the grid, and, thanks to the original "fill board" code, he hads a new one leaving the border clean and updated. – Laquitalar