Accessing Node in GridPane in javaFX and Rectangle casting

Question

I am working on a simple LiteBrite game using javaFX. Using a color picker, the user chooses a color and clocks on the GridPane which is a collection of Rectangles. Each click changes the color of that Rectangle to the one chosen by the user. However, if the color of the Rectangle has already been changed, I am expected to change the color back to the original (black). I am having trouble accessing the Node and casting it to Rectangle (in order to check the color). This is the method I am using to get a Node:

private Node getNode(GridPane grid, int column, int row){
      Node result = null; 
      for (Node node : grid.getChildren()) {
           if (GridPane.getColumnIndex(node) == column 
                   && GridPane.getRowIndex(node) == row) {
                result = node;
            }
      }
      return result;
}

In the start method I call the the above method and save the Node:

      Node node = getNode(grid,i,j);

At this point, if I try to print out node I have no problem. However, after I cast the Node into Rectangle and try to check its color I get a NULLPointerException:

       Rectangle rec = (Rectangle) node;
       System.out.println(rec.getFill());

What am I doing wrong? Any help is greatly appreciated. Thank you in advance.

Is it javafx built in Rectangle class or custom? Your code works perfectly fine by me. — Steven, Oct 04 '17 at 02:18
It is imported Rectangle class. I did an import statement at the beginning: import javafx.scene.shape.Rectangle; — Alexander Nenartovich, Oct 04 '17 at 03:51
For the default `0` index value `getColumnIndex`/`getRowIndex` may return `null` instead of `0` which yields a NPE when autounboxing the `Integer`... — fabian, Oct 04 '17 at 04:33
The method returns the Node because when I try to print it there is no problem (it is not null). The problem arises when I cast this same Node to Rectangle and try to call methods on this Rectangle. This is when NPE appears. — Alexander Nenartovich, Oct 04 '17 at 05:25
Can you post the rest of your code as well? This snippet works for me. — Steven, Oct 04 '17 at 05:57
Never mind, guys, I figured out another way of doing this. Thank you so much for your help and time. — Alexander Nenartovich, Oct 05 '17 at 04:17

Accessing Node in GridPane in javaFX and Rectangle casting

0 Answers0