如何拖放SAME tabpane的标签？

Question

我已经看到很多关于如何将tabpane的标签拖动到另一个标签上的方法,顺便说一下我没有看到这一点,我想它在某种程度上可能有用,但最自然的应用程序应该是重新排序标签的相同的tabpane,似乎没有人在互联网上谈论的事情.

我想要几乎所有浏览器都实现的行为.

我尝试了一些东西,但它没有做我想要的.主要的问题来自于一个事实,即Tab不能与约束setOnDragDetected,setOnDragOver导致过于复杂的算法来弥补图书馆的这一弱点等的方法(出于某种原因,通过的方式......脱离了我).

所以这是我的代码,它没有做我想要的,因为(而且它只是一种解决方法)我只检测掉落后的"丢弃目标",从而使它无用.是的,由于某些原因,在按住单击按钮的同时悬停对象不会导致mouseover事件...

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.scene.input.ClipboardContent;
import javafx.scene.input.Dragboard;
import javafx.scene.input.TransferMode;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;

public class DragAndDrop extends Application
{
    public void start(Stage primaryStage)
    {
        TabPane tabPane = new TabPane();

        final int[] target = {0};

        for(int i = 0 ; i < 2 ; i ++)
        {
            Tab tab = new Tab();
            tab.setClosable(false);

            int index[] = {i};

            tabPane.getTabs().add(tab);

            Label label = new Label("Tab " + (i + 1), new Rectangle(16, 16, Color.TRANSPARENT));
            tab.setGraphic(label);

            tab.getGraphic().setOnMouseEntered(event ->
            {
                target[0] = index[0];
                System.out.println("target : " + target[0]);
            });
        }

        tabPane.setOnDragDetected(event ->
        {
            Dragboard dragboard = tabPane.startDragAndDrop(TransferMode.ANY);

            ClipboardContent clipboardContent = new ClipboardContent();
            clipboardContent.putString(Integer.toString(tabPane.getSelectionModel().getSelectedIndex()));
            System.out.println("source : " + tabPane.getSelectionModel().getSelectedIndex());
            dragboard.setContent(clipboardContent);

            event.consume();
        });

        tabPane.setOnDragOver(event ->
        {
            if(event.getDragboard().hasString())
            {
                event.acceptTransferModes(TransferMode.COPY_OR_MOVE);
            }

            event.consume();
        });

        tabPane.setOnDragDropped(event ->
        {
            Dragboard dragboard = event.getDragboard();
            boolean success = false;

            if(dragboard.hasString())
            {
                System.out.println("from " + dragboard.getString() + " to " + target[0]);

                success = true;
            }

            event.setDropCompleted(success);
            event.consume();
        });

        tabPane.setOnDragDone(event ->
        {
            if(event.getTransferMode() == TransferMode.MOVE)
            {
                // tabPane.setText("");
            }
            event.consume();
        });

        primaryStage.setScene(new Scene(tabPane, 300, 200));
        primaryStage.show();
    }

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

Answer 1

我认为最简单的方法是使用与选项卡关联的图形来注册拖动处理程序,而不是使用选项卡窗格.这使得管理选项卡的索引等更容易一些,并且您不依赖于鼠标拖动操作和选择之间的相互作用(您实际上不知道这些将发生在哪个顺序).这种方法的缺点是,您必须确保每个选项卡都有一个图形(您可以使用标签作为图形来显示文本).

这是一个通用的"选项卡窗格拖动支持"类.无论如何,它并不意味着生产质量,但基础知识似乎有效.这里的想法是您创建一个DraggingTabPaneSupport实例并使用它来向一个或多个TabPanes 添加拖动支持.然后可以在任何窗格内或之间拖动标签.如果您希望只能在每个选项卡窗格中拖动,请为每个选项卡窗格创建一个DraggingTabPaneSupport实例.

import java.util.concurrent.atomic.AtomicLong;

import javafx.collections.ListChangeListener.Change;
import javafx.scene.Node;
import javafx.scene.control.Label;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.scene.input.ClipboardContent;
import javafx.scene.input.Dragboard;
import javafx.scene.input.TransferMode;

public class DraggingTabPaneSupport {

    private Tab currentDraggingTab ;

    private static final AtomicLong idGenerator = new AtomicLong();

    private final String draggingID = "DraggingTabPaneSupport-"+idGenerator.incrementAndGet() ;

    public void addSupport(TabPane tabPane) {
        tabPane.getTabs().forEach(this::addDragHandlers);
        tabPane.getTabs().addListener((Change<? extends Tab> c) -> {
            while (c.next()) {
                if (c.wasAdded()) {
                    c.getAddedSubList().forEach(this::addDragHandlers);
                }
                if (c.wasRemoved()) {
                    c.getRemoved().forEach(this::removeDragHandlers);
                }
            }
        });

        // if we drag onto a tab pane (but not onto the tab graphic), add the tab to the end of the list of tabs:
        tabPane.setOnDragOver(e -> {
            if (draggingID.equals(e.getDragboard().getString()) && 
                    currentDraggingTab != null &&
                    currentDraggingTab.getTabPane() != tabPane) {
                e.acceptTransferModes(TransferMode.MOVE);
            }
        });
        tabPane.setOnDragDropped(e -> {
            if (draggingID.equals(e.getDragboard().getString()) && 
                    currentDraggingTab != null &&
                    currentDraggingTab.getTabPane() != tabPane) {

                currentDraggingTab.getTabPane().getTabs().remove(currentDraggingTab);
                tabPane.getTabs().add(currentDraggingTab);
                currentDraggingTab.getTabPane().getSelectionModel().select(currentDraggingTab);
            }
        });
    }

    private void addDragHandlers(Tab tab) {

        // move text to label graphic:
        if (tab.getText() != null && ! tab.getText().isEmpty()) {
            Label label = new Label(tab.getText(), tab.getGraphic());
            tab.setText(null);
            tab.setGraphic(label);
        }

        Node graphic = tab.getGraphic();
        graphic.setOnDragDetected(e -> {
            Dragboard dragboard = graphic.startDragAndDrop(TransferMode.MOVE);
            ClipboardContent content = new ClipboardContent();
            // dragboard must have some content, but we need it to be a Tab, which isn't supported
            // So we store it in a local variable and just put arbitrary content in the dragbaord:
            content.putString(draggingID);
            dragboard.setContent(content);
            dragboard.setDragView(graphic.snapshot(null, null));
            currentDraggingTab = tab ;
        });
        graphic.setOnDragOver(e -> {
            if (draggingID.equals(e.getDragboard().getString()) && 
                    currentDraggingTab != null &&
                    currentDraggingTab.getGraphic() != graphic) {
                e.acceptTransferModes(TransferMode.MOVE);
            }
        });
        graphic.setOnDragDropped(e -> {
            if (draggingID.equals(e.getDragboard().getString()) && 
                    currentDraggingTab != null &&
                    currentDraggingTab.getGraphic() != graphic) {

                int index = tab.getTabPane().getTabs().indexOf(tab) ;
                currentDraggingTab.getTabPane().getTabs().remove(currentDraggingTab);
                tab.getTabPane().getTabs().add(index, currentDraggingTab);
                currentDraggingTab.getTabPane().getSelectionModel().select(currentDraggingTab);
            }
        });
        graphic.setOnDragDone(e -> currentDraggingTab = null);
    }

    private void removeDragHandlers(Tab tab) {
        tab.getGraphic().setOnDragDetected(null);
        tab.getGraphic().setOnDragOver(null);
        tab.getGraphic().setOnDragDropped(null);
        tab.getGraphic().setOnDragDone(null);
    }
}

这是一个使用它的快速示例.在这个例子中,我创建了三个选项卡窗格.我为前两个窗格创建了一个拖动支持实例,因此可以在这两个窗格之间拖动标签,为第三个窗格创建第二个拖动支持实例,因此在第三个窗格中可以通过拖动重新排序标签但不能拖动到另外两个窗格.

import java.util.Random;

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.scene.layout.Region;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;

public class DraggingTabPaneExample extends Application {

    private final Random rng = new Random();

    @Override
    public void start(Stage primaryStage) {
        TabPane[] panes = new TabPane[] {new TabPane(), new TabPane(), new TabPane() };
        VBox root = new VBox(10, panes);
        for (int i = 1 ; i <= 15; i++) {
            Tab tab = new Tab("Tab "+i);
            tab.setGraphic(new Rectangle(16, 16, randomColor()));
            Region region = new Region();
            region.setMinSize(100, 150);
            tab.setContent(region);
            panes[(i-1) % panes.length].getTabs().add(tab);
        }

        DraggingTabPaneSupport support1 = new DraggingTabPaneSupport();
        support1.addSupport(panes[0]);
        support1.addSupport(panes[1]);
        DraggingTabPaneSupport support2 = new DraggingTabPaneSupport();
        support2.addSupport(panes[2]);

        Scene scene = new Scene(root, 600, 600);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private Color randomColor() {
        return Color.rgb(rng.nextInt(256), rng.nextInt(256), rng.nextInt(256));
    }

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

初始截图:

在窗格中拖动后:

您也可以在前两个窗格之间拖动(但不能在第三个窗格和其他窗格之间拖动):