如何在 Javafx 2.0 中制作可拖动节点。JavaFX 专门用于 GUI 目的，我只需要一些示例，谢谢
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16
Oracle 提供了关于可拖动节点的教程。
这是makeDraggable教程中的方法：
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;
}
有时您不需要过滤器和拖动上下文，可以通过对各种鼠标事件进行操作来做一些更简单的事情，如下例所示：
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);
}
}
});
}
拖动节点的相同技术也可用于拖动阶段：
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);
}
}
});
}
用于拖动父节点（包含多个子节点）的示例。这个例子比上面的基于圆的例子更通用，因为它不依赖于大多数节点不具备的 centerX/Y 属性，而是适用于 layoutX/Y，这些属性可用于放置在父组或窗格中的所有节点.
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
如果您看到拖动的节点滞后于光标并希望解决该问题，请参阅 Xanatos 对以下内容的回答：
他建议您可能希望设置的地方：
-Dprism.vsync=false
于 2013-06-26T07:01:20.753 回答
8
聚会有点晚了，但我需要 Node 的许多子类中的可拖动性，所以我创建了一个实用程序类：
/**
* 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;
}
}
}
这可以应用于任何节点：
final Rectangle rectangle = new Rectangle(100, 100, 200, 50);
Draggable.Nature nature = new Draggable.Nature(rectangle);
并且矩形是可拖动的。您可以向 Draggable.Nature 添加侦听器，并且可以添加可以同时拖动的额外节点。
这解决了我的需求 - 希望它有所帮助。
于 2017-10-11T20:07:51.663 回答