在这种情况下，如何使setOnMouseDragOver工作？

Question

事件处理程序添加到GameGui.java类的GridPane中，从第82行开始。

基本上，我试图找到您在网格窗格中拖动这个对象的任何节点的索引。通过将SetonMouseEnter应用到gridpane中的每个节点，我可以在不拖动的情况下完成这一任务，但是当我试图利用SetonMouseDragEnter时，我什么也没有得到。

有人有办法让这个工作吗？

这些是我应用于GridPane中节点的事件处理程序。

    for (int i=0; i<=11; i++) {
        for (int j=0; j<=11; j++) {

            int colIndex = i;
            int rowIndex = j;

            grid2[i][j] = new Rectangle();
            grid2[i][j].setStroke(Color.BLACK);
            grid2[i][j].setFill(null);
            grid2[i][j].setStrokeWidth(1);
            grid2[i][j].setWidth(30);
            grid2[i][j].setHeight(30);
            //Prints index of each grid2[][] upon mouse entry.
            grid2[i][j].setOnMouseEntered( e -> {
                System.out.printf("Mouse entered cell [%d, %d]%n", colIndex, rowIndex);
            });
            //Does not work! Want to print index of each grid2[][] upon mouse drag enter.
            grid2[i][j].setOnMouseDragEntered( e -> {
                System.out.printf("Mouse entered cell [%d, %d]%n", colIndex, rowIndex);
            });
            //Does not work! Want to print index of each grid2[][] upon mouse drag over.
            grid2[i][j].setOnMouseDragOver( e -> {
                System.out.printf("Mouse entered cell [%d, %d]%n", colIndex, rowIndex);
            });

这些是当您按下其中一个按钮时创建的对象的事件处理程序。

private EventHandler<MouseEvent> onMousePressedEventHandler = event -> {
    if (event.getSource() instanceof Rectangle) {
        shipSelected = (Rectangle) (event.getSource());

        dragContext.x = shipSelected.getTranslateX() - shipSelected.getWidth()/2;
        dragContext.y = shipSelected.getTranslateY() - shipSelected.getHeight()/2;
    }
};


private EventHandler<MouseEvent> onMouseDragDetectedEventHandler = event -> {
    shipSelected.startFullDrag();

    System.out.println("startfulldrag");
};


private EventHandler<MouseEvent> onMouseDraggedEventHandler = event -> {
    if (event.getSource() instanceof Rectangle) {
        shipSelected = (Rectangle) (event.getSource());

        shipSelected.setX(dragContext.x + event.getX());
        shipSelected.setY(dragContext.y + event.getY());

    }
};

Answer 1

在拖动时，您需要使鼠标移动的矩形与setmouseTransparent(true)透明。

private EventHandler<MouseEvent> onMouseDragDetectedEventHandler = event -> {
    shipSelected.startFullDrag();
    shipSelected.setMouseTransparent(true)
    System.out.println("startfulldrag");
};

否则，矩形始终是鼠标指针下最顶部的元素，您将无法从下面的元素（即网格）获得dragEntered事件。

当然，不要忘记将鼠标透明度设置为false，当你结束拖动时。