Why does JavaFX only receive mouse events once? - javafx

Question

I'm working on an application where I can drag and drop an ImageView anywhere on to the scene. When I run the application it works fine the first time I drag the ImageView, but is unresponsive after I release it.
Here is my FXML Controller:
#FXML
private ImageView card;
#FXML
private void handleCardMousePressed(MouseEvent event) {
System.out.println("Drag Entered");
DropShadow dropShadow=new DropShadow();
dropShadow.setColor(Color.rgb(18,139,237));
dropShadow.setSpread(.48);
card.setEffect(dropShadow);
card.setMouseTransparent(true);
event.consume();
}
#FXML
private void handleCardMouseDragged(MouseEvent event){
System.out.println("In Drag");
card.setLayoutX(event.getSceneX());
card.setLayoutY(event.getSceneY());
event.consume();
}
#FXML
private void handleCardMouseReleased(MouseEvent event){
System.out.println("Exit Drag");
card.setEffect(null);
event.consume();
}
Video of What is Happening

Answer 1

Don't set mouseTransparent to true in the handleMouseCardPressed method.
If you need to do this for some other reason (I can't see why you would), then in handleCardMouseReleased(...) you need to set mouseTransparent back to false:
card.setMouseTransparent(false);
Complete example:
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.effect.DropShadow;
import javafx.scene.image.ImageView;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;
public class DragImageViewExample extends Application {
private ImageView card;
#Override
public void start(Stage primaryStage) {
Rectangle rect = new Rectangle(30, 30, Color.CORAL);
card = new ImageView(rect.snapshot(null, null));
card.setOnMousePressed(this::handleCardMousePressed);
card.setOnMouseDragged(this::handleCardMouseDragged);
card.setOnMouseReleased(this::handleCardMouseReleased);
Pane pane = new Pane(card);
Scene scene = new Scene(pane, 600, 400);
primaryStage.setScene(scene);
primaryStage.show();
}
private void handleCardMousePressed(MouseEvent event) {
System.out.println("Drag Entered");
DropShadow dropShadow=new DropShadow();
dropShadow.setColor(Color.rgb(18,139,237));
dropShadow.setSpread(.48);
card.setEffect(dropShadow);
event.consume();
}
private void handleCardMouseDragged(MouseEvent event){
System.out.println("In Drag");
card.setLayoutX(event.getSceneX());
card.setLayoutY(event.getSceneY());
event.consume();
}
private void handleCardMouseReleased(MouseEvent event){
System.out.println("Exit Drag");
card.setEffect(null);
event.consume();
}
public static void main(String[] args) {
launch(args);
}
}