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  1. JDK
  2. JDK-8027913

drop target notifications are sent out of order during DnD

    Details

    • Subcomponent:
    • Resolved In Build:
      b119
    • CPU:
      generic
    • OS:
      os_x

      Description

      This issue was found while working on the following JavaFX bug:

      https://javafx-jira.kenai.com/browse/RT-28347

      What I observe is that when a JFXPanel object acts as a drop target, dragEnter(), dragOver(), and dragExit() notifications can be sent to its DropTargetListener in a wrong order. For example:

      drag enter
      drag over
      drag exit
      drag over

      or

      drag enter
      drag enter

      To reproduce the bug, run the following JavaFX/Swing test and drag-n-drop from and to the FX scene:

                  JFrame f = new JFrame("F");
                  f.setBounds(400, 100, 320, 240);

                  JFXPanel p1 = new JFXPanel();
                  Platform.runLater(() -> {
                      Text t = new Text("Drag from here");
                      t.setStyle("-fx-font-size: 32px");
                      t.setOnDragDetected(new EventHandler<MouseEvent>() {
                          @Override
                          public void handle(MouseEvent event) {
                              Dragboard db = t.startDragAndDrop(TransferMode.COPY);
                              ClipboardContent content = new ClipboardContent();
                              content.putString("FX TEXT");
                              db.setContent(content);
                              event.consume();
                          }
                      });
                      t.setOnDragDone(new EventHandler<DragEvent>() {
                          @Override
                          public void handle(DragEvent event) {
                              t.setText("Drag done");
                          }
                      });
                      Text t2 = new Text("Drop here");
                      t2.setStyle("-fx-font-size: 32px");
                      t2.setOnDragEntered(new EventHandler<DragEvent>() {
                          @Override
                          public void handle(DragEvent event) {
                              System.out.println(event.getDragboard().getContentTypes());
                              event.acceptTransferModes(TransferMode.ANY);
                              event.consume();
                          }
                      });
                      t2.setOnDragOver((event) -> {
                          event.acceptTransferModes(TransferMode.ANY);
                          event.consume();
                      });
                      t2.setOnDragDropped(new EventHandler<DragEvent>() {
                          @Override
                          public void handle(DragEvent event) {
                              t2.setText(event.getDragboard().getString());
                              event.setDropCompleted(true);
                              event.consume();
                          }
                      });
                      Scene s = new Scene(new FlowPane(t, t2), Color.RED);
                      p1.setScene(s);
                  });
                  f.add(p1);

                  f.setVisible(true);

      If you see exceptions (or assertion errors, when run with -ea), the bug is reproduced. These exceptions are observed on Mac, but not on Windows, both before and after the fix for RT-28347.

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            • Assignee:
              serb Sergey Bylokhov
              Reporter:
              art Artem Ananiev
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              • Created:
                Updated:
                Resolved: