如何在Java中将一个对象强制转换为另一个对象？ “ javafx.scene.Group无法转换为javafx.scene.shape.Rectangle”

Question

How can I change the attributes of objects that are stored in a grid? I tried this, but it gives me the above error:

    Group group = new Group();
    double dimension_x=100;
    double dimension_y=100;

    GridPane grid = new GridPane();
    grid.setHgap(1);
    grid.setVgap(1);
    grid.setPadding(new Insets(36));
    grid.setGridLinesVisible(true);

    Rectangle temp = new Rectangle(dimension_x,dimension_y);
    Rectangle temp2 = new Rectangle(dimension_x,dimension_y);
    Rectangle temp3 = new Rectangle(dimension_x,dimension_y);
    Rectangle temp4 = new Rectangle(dimension_x,dimension_y);

    grid.add(temp, 0,0);
    grid.add(temp2, 1,1);
    grid.add(temp3, 2,2);
    grid.add(temp4, 3,3);

    for (final Node node : grid.getChildren())
    {

        Rectangle tempvar = (Rectangle) node;  //Errors out at javafx.scene.Group cannot be cast to javafx.scene.shape.Rectangle
        node.getStyleClass().add("box");
        //tempvar.setFill(Color.TRANSPARENT);
        //tempvar.setStroke(Color.WHITE);

    }

is there any way to loop through my grid and change the objects?

Answer 1

Print the result of grid.getChildren() .

I'm suspicious that grid contains other objects other those 4 Rectangle