Question

我试图通过实施国际象棋游戏来学习JavaFX。我的问题是我不知道如何通过拖放来移动一块。在我的代码中，我有一个2D标签数组，其中label包含一个ImageView。我想知道如何确定拖动片下的另一个片段（节点）。提前谢谢。

Answer 1

基本上，您必须对要拖动的项目使用setOnDragDetected()方法，然后使用目标项目上的setOnDragOver()来确定哪个TransferMode正在接受setOnDragDropped()在完成放置时使用目标方法。最后setOnDragComplete()在原始项目上确定拖动是否成功。

1）链接以获取来自oracle here

的更多信息

2）一个很好的例子here

3）第二个容易理解的例子：

    /**
 * Demonstrates a drag-and-drop feature.
 */
public class HelloDragAndDrop extends Application {

    @Override
    public void start(Stage stage) {
        stage.setTitle("Hello Drag And Drop");

        Group root = new Group();
        Scene scene = new Scene(root, 400, 200);
        scene.setFill(Color.LIGHTGREEN);

        final Text source = new Text(50, 100, "DRAG ME");
        source.setScaleX(2.0);
        source.setScaleY(2.0);

        final Text target = new Text(250, 100, "DROP HERE");
        target.setScaleX(2.0);
        target.setScaleY(2.0);

        source.setOnDragDetected(event -> {
            /* drag was detected, start drag-and-drop gesture */
            System.out.println("onDragDetected");

            /* allow any transfer mode */
            Dragboard db = source.startDragAndDrop(TransferMode.ANY);

            /* put a string on dragboard */
            ClipboardContent content = new ClipboardContent();
            content.putString(source.getText());
            db.setContent(content);

            event.consume();
        });

        target.setOnDragOver(event -> {
            /* data is dragged over the target */
            System.out.println("onDragOver");

            /*
             * 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 both copying and moving, whatever user chooses */
                event.acceptTransferModes(TransferMode.COPY_OR_MOVE);
            }

            event.consume();
        });

        target.setOnDragEntered(event -> {
            /* the drag-and-drop gesture entered the target */
            System.out.println("onDragEntered");
            /* show to the user that it is an actual gesture target */
            if (event.getGestureSource() != target && event.getDragboard().hasString()) {
                target.setFill(Color.GREEN);
            }

            event.consume();
        });

        target.setOnDragExited(event -> {
            /* mouse moved away, remove the graphical cues */
            target.setFill(Color.BLACK);

            event.consume();
        });

        target.setOnDragDropped(event -> {
            /* data dropped */
            System.out.println("onDragDropped");
            /* 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();
        });

        source.setOnDragDone(event -> {
            /* the drag-and-drop gesture ended */
            System.out.println("onDragDone");
            /* if the data was successfully moved, clear it */
            if (event.getTransferMode() == TransferMode.MOVE) {
                source.setText("");
            }

            event.consume();
        });

        root.getChildren().add(source);
        root.getChildren().add(target);
        stage.setScene(scene);
        stage.show();
    }

    public static void main(String[] args) {
        Application.launch(args);
    }
}

将节点拖放到另一个节点

1 个答案: