7 ドラッグ・アンド・ドロップ操作

例7-2

source.setOnDragDetected(new EventHandler<MouseEvent>() {
    public void handle(MouseEvent event) {
        /* drag was detected, start a drag-and-drop gesture*/
        /* allow any transfer mode */
        Dragboard db = source.startDragAndDrop(TransferMode.ANY);
        
        /* Put a string on a dragboard */
        ClipboardContent content = new ClipboardContent();
        content.putString(source.getText());
        db.setContent(content);
        
        event.consume();
    }
});

例7-3

target.setOnDragOver(new EventHandler<DragEvent>() {
    public void handle(DragEvent event) {
        /* data is dragged over the target */
        /* accept it only if it is not dragged from the same node 
         * and if it has a string data */
        if (event.getGestureSource() != target &&
                event.getDragboard().hasString()) {
            /* allow for moving */
            event.acceptTransferModes(TransferMode.MOVE);
        }
        
        event.consume();
    }
});

例7-4

target.setOnDragEntered(new EventHandler<DragEvent>() {
    public void handle(DragEvent event) {
    /* the drag-and-drop gesture entered the target */
    /* show to the user that it is an actual gesture target */
         if (event.getGestureSource() != target &&
                 event.getDragboard().hasString()) {
             target.setFill(Color.GREEN);
         }
                
         event.consume();
    }
});

例7-5

target.setOnDragExited(new EventHandler<DragEvent>() {
    public void handle(DragEvent event) {
        /* mouse moved away, remove the graphical cues */
        target.setFill(Color.BLACK);

        event.consume();
    }
});

例7-6

target.setOnDragDropped(new EventHandler<DragEvent>() {
    public void handle(DragEvent event) {
        /* data dropped */
        /* if there is a string data on dragboard, read it and use it */
        Dragboard db = event.getDragboard();
        boolean success = false;
        if (db.hasString()) {
           target.setText(db.getString());
           success = true;
        }
        /* let the source know whether the string was successfully 
         * transferred and used */
        event.setDropCompleted(success);
        
        event.consume();
     }
});

例7-7

source.setOnDragDone(new EventHandler<DragEvent>() {
    public void handle(DragEvent event) {
        /* the drag and drop gesture ended */
        /* if the data was successfully moved, clear it */
        if (event.getTransferMode() == TransferMode.MOVE) {
            source.setText("");
        }
        event.consume();
    }
});

例7-8

/** The custom format */
private static final DataFormat customFormat =
    new DataFormat("helloworld.custom");