javafx - Assigning a MouseListener to each Region in a 2d array of Regions -

i posted question here couple weeks ago on making chess game , got great response , code demonstrates solution problem. have been trying dissect code , study can better understand how works. while doing ran question can not seem find answer for. chess board made of 2d array of regions , trying add mouselistener each region in 2d array when region pressed print out row , column of region pressed. right nothing happening when press on square in screen , can't not figure out why mouselistener not working.

 public class main extends application {  gridpane root = new gridpane();  final int size = 8;  int col = 0;  int row = 0;    @override  public void start(stage primarystage) {     try {           gridpane board = new gridpane();         region[][] fields = new region[8][8];         (int = 0; < fields.length; i++) {             region[] flds = fields[i];             (int j = 0; j < flds.length; j++) {                 region field = new region();                 flds[j] = field;                 field.setbackground(new background(new backgroundfill((i + j) % 2 == 0 ? color.white : color.lightblue, cornerradii.empty, insets.empty)));              }             board.addrow(i, flds);         }          (int = 0; < fields.length; i++) {             col = i;             (int j = 0; j < fields[i].length; j++) {                 row = j;                 fields[i][j].setonmouseclicked(e->{                     system.out.println("col:" + col + ", row" + row);                 });             }         }           // use 1/8 of size of grid each field         rowconstraints rowconstraints = new rowconstraints();         rowconstraints.setpercentheight(100d / 8);         columnconstraints columnconstraints = new columnconstraints();         columnconstraints.setpercentwidth(100d / 8);          (int = 0; < 8; i++) {             board.getcolumnconstraints().add(columnconstraints);             board.getrowconstraints().add(rowconstraints);         }          pane piecepane = new pane();         stackpane root = new stackpane(board, piecepane);         // numberbinding boardsize = bindings.min(root.widthproperty(), root.heightproperty());         numberbinding boardsize = bindings.min(root.widthproperty(), root.heightproperty());          // board size should large possible @ min of parent sizes         board.setprefsize(double.max_value, double.max_value);          // same size piecepane         piecepane.setprefsize(double.max_value, double.max_value);         piecepane.maxwidthproperty().bind(boardsize);         piecepane.maxheightproperty().bind(boardsize);          scene scene = new scene(root,400,400);         primarystage.setscene(scene);         primarystage.show();     } catch(exception e) {         e.printstacktrace();     } }   public static void main(string[] args) {     launch(args);  } } 

change:

stackpane root = new stackpane(board,piecepane); 

to:

stackpane root = new stackpane(piecepane,board); 

🐞? because board behind piecepane couldn't receive events.

before using global variables col , row these variables had same value of 7 , 7. running loop variables changing value,but @ end had values 7 7 , here need use local variables col , row , need add modification:

            (int = 0; < fields.length; i++) {                 int col = i;                 (int j = 0; j < fields[i].length; j++) {                     int row = j;                     fields[i][j].setonmouseclicked(e -> system.out.println("col:" + col + ", row" + row));                 }             }