如何在Javafx 2.0中创建一个Draggable节点。

如何在Javafx 2.0中创建一个Draggable节点。 JavaFX专门用于GUI目的只有我需要一些示例谢谢如何在Javafx 2.0中创建一个Draggable节点。

2013-06-26 user2508146

下面是本教程的makeDraggable方法：

private Node makeDraggable(final Node node) { 
final DragContext dragContext = new DragContext(); 
final Group wrapGroup = new Group(node); 

wrapGroup.addEventFilter(
    MouseEvent.ANY, 
    new EventHandler<MouseEvent>() { 
     public void handle(final MouseEvent mouseEvent) { 
      if (dragModeActiveProperty.get()) { 
       // disable mouse events for all children 
       mouseEvent.consume(); 
      } 
     } 
    }); 

wrapGroup.addEventFilter(
    MouseEvent.MOUSE_PRESSED, 
    new EventHandler<MouseEvent>() { 
     public void handle(final MouseEvent mouseEvent) { 
      if (dragModeActiveProperty.get()) { 
       // remember initial mouse cursor coordinates 
       // and node position 
       dragContext.mouseAnchorX = mouseEvent.getX(); 
       dragContext.mouseAnchorY = mouseEvent.getY(); 
       dragContext.initialTranslateX = 
        node.getTranslateX(); 
       dragContext.initialTranslateY = 
        node.getTranslateY(); 
      } 
     } 
    }); 

wrapGroup.addEventFilter(
    MouseEvent.MOUSE_DRAGGED, 
    new EventHandler<MouseEvent>() { 
     public void handle(final MouseEvent mouseEvent) { 
      if (dragModeActiveProperty.get()) { 
       // shift node from its initial position by delta 
       // calculated from mouse cursor movement 
       node.setTranslateX(
        dragContext.initialTranslateX 
         + mouseEvent.getX() 
         - dragContext.mouseAnchorX); 
       node.setTranslateY(
        dragContext.initialTranslateY 
         + mouseEvent.getY() 
         - dragContext.mouseAnchorY); 
      } 
     } 
    }); 

return wrapGroup; 

}

有时候，你并不需要过滤器和阻力背景和可以做简单的东西通过作用于像各种鼠标事件在此example：

static class Delta { double x, y; } 
// make a node movable by dragging it around with the mouse. 
private void enableDrag(final Circle circle) { 
final Delta dragDelta = new Delta(); 
circle.setOnMousePressed(new EventHandler<MouseEvent>() { 
    @Override public void handle(MouseEvent mouseEvent) { 
    // record a delta distance for the drag and drop operation. 
    dragDelta.x = circle.getCenterX() - mouseEvent.getX(); 
    dragDelta.y = circle.getCenterY() - mouseEvent.getY(); 
    circle.getScene().setCursor(Cursor.MOVE); 
    } 
}); 
circle.setOnMouseReleased(new EventHandler<MouseEvent>() { 
    @Override public void handle(MouseEvent mouseEvent) { 
    circle.getScene().setCursor(Cursor.HAND); 
    } 
}); 
circle.setOnMouseDragged(new EventHandler<MouseEvent>() { 
    @Override public void handle(MouseEvent mouseEvent) { 
    circle.setCenterX(mouseEvent.getX() + dragDelta.x); 
    circle.setCenterY(mouseEvent.getY() + dragDelta.y); 
    } 
}); 
circle.setOnMouseEntered(new EventHandler<MouseEvent>() { 
    @Override public void handle(MouseEvent mouseEvent) { 
    if (!mouseEvent.isPrimaryButtonDown()) { 
     circle.getScene().setCursor(Cursor.HAND); 
    } 
    } 
}); 
circle.setOnMouseExited(new EventHandler<MouseEvent>() { 
    @Override public void handle(MouseEvent mouseEvent) { 
    if (!mouseEvent.isPrimaryButtonDown()) { 
     circle.getScene().setCursor(Cursor.DEFAULT); 
    } 
    } 
}); 
}

周边的拖动节点相同的技术也可以被用来drag around stages：

static class Delta { double x, y; } 
/** makes a stage draggable using a given node */ 
public static void makeDraggable(final Stage stage, final Node byNode) { 
final Delta dragDelta = new Delta(); 
byNode.setOnMousePressed(new EventHandler<MouseEvent>() { 
    @Override public void handle(MouseEvent mouseEvent) { 
    // record a delta distance for the drag and drop operation. 
    dragDelta.x = stage.getX() - mouseEvent.getScreenX(); 
    dragDelta.y = stage.getY() - mouseEvent.getScreenY(); 
    byNode.setCursor(Cursor.MOVE); 
    } 
}); 
byNode.setOnMouseReleased(new EventHandler<MouseEvent>() { 
    @Override public void handle(MouseEvent mouseEvent) { 
    byNode.setCursor(Cursor.HAND); 
    } 
}); 
byNode.setOnMouseDragged(new EventHandler<MouseEvent>() { 
    @Override public void handle(MouseEvent mouseEvent) { 
    stage.setX(mouseEvent.getScreenX() + dragDelta.x); 
    stage.setY(mouseEvent.getScreenY() + dragDelta.y); 
    } 
}); 
byNode.setOnMouseEntered(new EventHandler<MouseEvent>() { 
    @Override public void handle(MouseEvent mouseEvent) { 
    if (!mouseEvent.isPrimaryButtonDown()) { 
     byNode.setCursor(Cursor.HAND); 
    } 
    } 
}); 
byNode.setOnMouseExited(new EventHandler<MouseEvent>() { 
    @Override public void handle(MouseEvent mouseEvent) { 
    if (!mouseEvent.isPrimaryButtonDown()) { 
     byNode.setCursor(Cursor.DEFAULT); 
    } 
    } 
}); 
}

拖动父节点（包含多个子节点）的示例。这个例子比上面基于圆的例子更通用，因为它不依赖于大多数节点没有的centerX/Y属性，而是在layoutX/Y上工作，它们可以放置在父组或窗格中的所有节点上。

import javafx.application.Application; 
import javafx.scene.*; 
import javafx.scene.layout.*; 
import javafx.scene.paint.Color; 
import javafx.scene.shape.Circle; 
import javafx.scene.text.Text; 
import javafx.scene.text.TextBoundsType; 
import javafx.stage.Stage; 

public class TextOnCircleWithDragging extends Application { 
    private static final int W = 400; 
    private static final int H = 400; 
    private static final int R = 15; 

    @Override 
    public void start(Stage stage) { 
     final StackPane circleWithText = new StackPane(
       createCircle(), 
       createText() 
     ); 
     circleWithText.relocate(
       W/2 - R/2, 
       H/2 - R/2 
     ); 

     makeDraggable(circleWithText); 

     stage.setScene(
       new Scene(
         new Pane(circleWithText), 
         W, H 
       ) 
     ); 
     stage.show(); 
    } 

    private Circle createCircle() { 
     final Circle circle = new Circle(R); 
     circle.setFill(Color.PALEGREEN); 
     circle.relocate(0, 0); 

     return circle; 
    } 

    private Text createText() { 
     final Text text = new Text("A"); 
     text.setBoundsType(TextBoundsType.VISUAL); 

     return text; 
    } 

    private void makeDraggable(Node node) { 
     final Delta dragDelta = new Delta(); 

     node.setOnMouseEntered(me -> { 
      if (!me.isPrimaryButtonDown()) { 
       node.getScene().setCursor(Cursor.HAND); 
      } 
     }); 
     node.setOnMouseExited(me -> { 
      if (!me.isPrimaryButtonDown()) { 
       node.getScene().setCursor(Cursor.DEFAULT); 
      } 
     }); 
     node.setOnMousePressed(me -> { 
      if (me.isPrimaryButtonDown()) { 
       node.getScene().setCursor(Cursor.DEFAULT); 
      } 
      dragDelta.x = me.getX(); 
      dragDelta.y = me.getY(); 
      node.getScene().setCursor(Cursor.MOVE); 
     }); 
     node.setOnMouseReleased(me -> { 
      if (!me.isPrimaryButtonDown()) { 
       node.getScene().setCursor(Cursor.DEFAULT); 
      } 
     }); 
     node.setOnMouseDragged(me -> { 
      node.setLayoutX(node.getLayoutX() + me.getX() - dragDelta.x); 
      node.setLayoutY(node.getLayoutY() + me.getY() - dragDelta.y); 
     }); 
    } 

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

    private class Delta { 
     public double x; 
     public double y; 
    } 
}

滞后调整

如果您看到光标后面拖着节点滞后和希望解决这一问题，然后看看萨那托斯的回答：

https://stackoverflow.com/a/22695105/1155209

他建议你在哪里设置：

-Dprism.vsync=false

解决方法问题https://bugs.openjdk.java.net/browse/JDK-8087922。

来源

2013-06-26 07:01:20 jewelsea

有点迟到了，但我需要draggability在节点的许多subclassses，所以我创建了一个工具类里面：

/** 
* Generalised implementation of 'Draggability' of a {@link Node}. The Draggable class is used as a 'namespace' for the internal 
* class/interfaces/enum. 
* @author phill 
* 
*/ 
public class Draggable { 
public enum Event { 
    None, DragStart, Drag, DragEnd 
} 

/** 
* Marker for an entity that has draggable nature. 
* @author phill 
*/ 
public interface Interface { 
    public abstract Draggable.Nature getDraggableNature(); 
} 

public interface Listener { 
    public void accept(Nature draggableNature, Event dragEvent); 
} 

/** 
* Class that encapsulates the draggable nature of a node. 
* <ul> 
* <li>EventNode: the event that receives the drag events</li> 
* <li>One or more DragNodes: that move in response to the drag events. The EventNode is usually (but not always) a 
* DragNode</li> 
* <li>Listeners: listen for the drag events</li> 
* </ul> 
* @author phill 
* 
*/ 
public static final class Nature implements EventHandler<MouseEvent> { 
    private double lastMouseX = 0, lastMouseY = 0; // scene coords 

    private boolean dragging = false; 

    private final boolean enabled = true; 
    private final Node eventNode; 
    private final List<Node> dragNodes = new ArrayList<>(); 
    private final List<Listener> dragListeners = new ArrayList<>(); 

    public Nature(final Node node) { 
     this(node, node); 
    } 

    public Nature(final Node eventNode, final Node... dragNodes) { 
     this.eventNode = eventNode; 
     this.dragNodes.addAll(Arrays.asList(dragNodes)); 
     this.eventNode.addEventHandler(MouseEvent.ANY, this); 
    } 

    public final boolean addDraggedNode(final Node node) { 
     if (!this.dragNodes.contains(node)) { 
      return this.dragNodes.add(node); 
     } 
     return false; 
    } 

    public final boolean addListener(final Listener listener) { 
     return this.dragListeners.add(listener); 
    } 

    public final void detatch() { 
     this.eventNode.removeEventFilter(MouseEvent.ANY, this); 
    } 

    public final List<Node> getDragNodes() { 
     return new ArrayList<>(this.dragNodes); 
    } 

    public final Node getEventNode() { 
     return this.eventNode; 
    } 

    @Override 
    public final void handle(final MouseEvent event) { 
     if (MouseEvent.MOUSE_PRESSED == event.getEventType()) { 
      if (this.enabled && this.eventNode.contains(event.getX(), event.getY())) { 
       this.lastMouseX = event.getSceneX(); 
       this.lastMouseY = event.getSceneY(); 
       event.consume(); 
      } 
     } else if (MouseEvent.MOUSE_DRAGGED == event.getEventType()) { 
      if (!this.dragging) { 
       this.dragging = true; 
       for (final Listener listener : this.dragListeners) { 
        listener.accept(this, Draggable.Event.DragStart); 
       } 
      } 
      if (this.dragging) { 
       final double deltaX = event.getSceneX() - this.lastMouseX; 
       final double deltaY = event.getSceneY() - this.lastMouseY; 

       for (final Node dragNode : this.dragNodes) { 
        final double initialTranslateX = dragNode.getTranslateX(); 
        final double initialTranslateY = dragNode.getTranslateY(); 
        dragNode.setTranslateX(initialTranslateX + deltaX); 
        dragNode.setTranslateY(initialTranslateY + deltaY); 
       } 

       this.lastMouseX = event.getSceneX(); 
       this.lastMouseY = event.getSceneY(); 

       event.consume(); 
       for (final Listener listener : this.dragListeners) { 
        listener.accept(this, Draggable.Event.Drag); 
       } 
      } 
     } else if (MouseEvent.MOUSE_RELEASED == event.getEventType()) { 
      if (this.dragging) { 
       event.consume(); 
       this.dragging = false; 
       for (final Listener listener : this.dragListeners) { 
        listener.accept(this, Draggable.Event.DragEnd); 
       } 
      } 
     } 

    } 

    public final boolean removeDraggedNode(final Node node) { 
     return this.dragNodes.remove(node); 
    } 

    public final boolean removeListener(final Listener listener) { 
     return this.dragListeners.remove(listener); 
    } 

    /** 
    * When the initial mousePressed is missing we can supply the first coordinates programmatically. 
    * @param lastMouseX 
    * @param lastMouseY 
    */ 
    public final void setLastMouse(final double lastMouseX, final double lastMouseY) { 
     this.lastMouseX = lastMouseX; 
     this.lastMouseY = lastMouseY; 
    } 
} 
}

这可以被应用到任何节点：

final Rectangle rectangle = new Rectangle(100, 100, 200, 50); 
Draggable.Nature nature = new Draggable.Nature(rectangle);

矩形是可拖动的。您可以将侦听器添加到Draggable.Nature，并且您可以添加可以同时拖动的额外节点。

这解决了我的需求 - 希望它有帮助。

来源

2017-10-11 20:07:51 DrPhill

如何在Javafx 2.0中创建一个Draggable节点。

回答

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