Clearing the scene in javafx - javafx

Question

I need a help with JavaFX. I have a program that draws lines with the mouse in the scene. When I press clear button, whole scene needs to be cleared. But only last drawn line is being cleared with this program.
When clear button is pushed, all drawn lines should be cleared. Now, only the last drawn line is being cleared.
public class Test extends Application {
private Line currentLine;
private Group root;
private ColorPicker colorPicker;
private Button clearButton;
private HBox buttons;
private Scene scene;
public void start(Stage primaryStage) {
root = new Group();
colorPicker = new ColorPicker(Color.WHITE);
clearButton = new Button("Clear");
clearButton.setOnAction(this::processActionButton);
buttons = new HBox(colorPicker, clearButton);
buttons.setSpacing(15);
root.getChildren().addAll(buttons);
scene = new Scene(root, 500, 300, Color.BLACK);
scene.setOnMousePressed(this::processMousePress);
scene.setOnMouseDragged(this::processMouseDrag);
primaryStage.setTitle("Color Lines");
primaryStage.setScene(scene);
primaryStage.show();
}
public void processMousePress(MouseEvent event) {
currentLine = new Line(event.getX(), event.getY(), event.getX(),
event.getY());
currentLine.setStroke(colorPicker.getValue());
currentLine.setStrokeWidth(3);
root.getChildren().add(currentLine);
}
public void processMouseDrag(MouseEvent event) {
currentLine.setEndX(event.getX());
currentLine.setEndY(event.getY());
}
public void processActionButton(ActionEvent event) {
root.getChildren().removeAll(currentLine);
}
public static void main(String[] args) {
launch(args);
}
}

Answer 1

You can have a special group for lines only:
Group groupLines = new Group();
...
root.getChildren().add(groupLines);
Add new lines into this group:
public void processMousePress(MouseEvent event) {
...
groupLines.getChildren().add(currentLine);
}
And clean only this group:
groupLines.getChildren().clear();