爲其父窗格內的可拖動窗格設置邊界限制

Question

我有一個可拖動窗格位於另一個窗格內。我想讓子窗格只能在父窗格的邊界內拖動，但默認情況下，子窗格可以在任何地方拖動。如何解決這個問題呢。

Answer 1

看看這個demo。該應用程序生成可在整個場景中移動的可拖動標籤。要設置邊界限制，使用以下技術：在onMouseDragged處理程序中，我們計算節點的當前位置，如果它不滿足某些條件，我們不會修改它。特別是：

label.setOnMouseDragged(new EventHandler<MouseEvent>() { 
    @Override public void handle(MouseEvent mouseEvent) { 

     //Sets the drag boundaries limit 
     double newX = mouseEvent.getSceneX() + dragDelta.x; 
     if (newX > 200 || newX < 10) { 
     return; 
     } 

     label.setLayoutX(mouseEvent.getSceneX() + dragDelta.x); 
     label.setLayoutY(mouseEvent.getSceneY() + dragDelta.y); 
    } 
    }); 

Answer 2

添加到xuesheng answer，而不是

if (newX > 200 || newX < 10) { return; } 

使用

if(outSideParentBounds(label.getLayoutBounds(), newX, newY)) { return; } 

凡outSideParentBounds被定義爲：

private boolean outSideParentBounds(Bounds childBounds, double newX, double newY) { 

     Bounds parentBounds = getLayoutBounds(); 

     //check if too left 
     if(parentBounds.getMaxX() <= (newX + childBounds.getMaxX())) { 
      return true ; 
     } 

     //check if too right 
     if(parentBounds.getMinX() >= (newX + childBounds.getMinX())) { 
      return true ; 
     } 

     //check if too down 
     if(parentBounds.getMaxY() <= (newY + childBounds.getMaxY())) { 
      return true ; 
     } 

     //check if too up 
     if(parentBounds.getMinY() >= (newY + childBounds.getMinY())) { 
      return true ; 
     } 

     return false; 

     /* Alternative implementation 
     Point2D topLeft = new Point2D(newX + childBounds.getMinX(), newY + childBounds.getMinY()); 
     Point2D topRight = new Point2D(newX + childBounds.getMaxX(), newY + childBounds.getMinY()); 
     Point2D bottomLeft = new Point2D(newX + childBounds.getMinX(), newY + childBounds.getMaxY()); 
     Point2D bottomRight = new Point2D(newX + childBounds.getMaxX(), newY + childBounds.getMaxY()); 
     Bounds newBounds = BoundsUtils.createBoundingBox(topLeft, topRight, bottomLeft, bottomRight); 

     return ! parentBounds.contains(newBounds); 
     */ 
    }