Re: [cp-patches] FYI: Fixed ScrollPaneLayout

[David Gilbert]

Roman Kennke wrote:

> The ScrollPaneLayout implementation has been wrong in several places.
> First, the minimum/preferredLayoutSize methods actually modified the
> layout, which is not allowed and can have severe performance impact and
> malfunction. Second, the layoutContainer method could not properly
> determine when the scrollbars should be visible or not. This has lead to
> ugly flickers.
>
> 2005-10-12  Roman Kennke  <address@hidden>
>
>        * javax/swing/ScrollPaneLayout.java
>        (preferredLayoutSize): Reworked. The old impl used to actually
>        modify the layout, which is not allowed.
>        (minimumLayoutSize): Reworked. The old impl used to actually
>        modify the layout, which is not allowed.
>        (layoutContainer): Reworked. The old impl did not properly
> determine
>        when the scrollbars should be visible and when not.
>
> /Roman
>  
>
> ------------------------------------------------------------------------
I don't know if this patch caused the problem, but something today has 
made the Swing demo fail (on the List world tab):

java.lang.NullPointerException
  at javax.swing.ScrollPaneLayout.minimumLayoutSize 
(ScrollPaneLayout.java:290)
  at javax.swing.plaf.basic.BasicScrollPaneUI.getMinimumSize 
(BasicScrollPaneUI.java:416)
  at javax.swing.JComponent.getMinimumSize (JComponent.java:1053)
  at 
javax.swing.plaf.basic.BasicSplitPaneUI$BasicHorizontalLayoutManager.minimumSizeOfComponent 
(BasicSplitPaneUI.java:481)
  at javax.swing.plaf.basic.BasicSplitPaneUI.getMinimumDividerLocation 
(BasicSplitPaneUI.java:1362)
  at javax.swing.plaf.basic.BasicSplitPaneUI.validLocation 
(BasicSplitPaneUI.java:1570)
  at javax.swing.plaf.basic.BasicSplitPaneUI.finishDraggingTo 
(BasicSplitPaneUI.java:1537)
  at javax.swing.plaf.basic.BasicSplitPaneDivider.finishDraggingTo 
(BasicSplitPaneDivider.java:489)
  at 
javax.swing.plaf.basic.BasicSplitPaneDivider$DragController.completeDrag 
(BasicSplitPaneDivider.java:719)
  at 
javax.swing.plaf.basic.BasicSplitPaneDivider$MouseHandler.mouseReleased 
(BasicSplitPaneDivider.java:586)
  at java.awt.Component.processMouseEvent (Component.java:3111)
  at java.awt.Component.processEvent (Component.java:2972)
  at java.awt.Container.processEvent (Container.java:905)
  at java.awt.Component.dispatchEventImpl (Component.java:4840)
  at java.awt.Container.dispatchEventImpl (Container.java:1644)
  at java.awt.Component.dispatchEvent (Component.java:2339)
  at java.awt.LightweightDispatcher.handleEvent (Container.java:2190)
  at java.awt.Container.dispatchEventImpl (Container.java:1635)
  at java.awt.Window.dispatchEventImpl (Window.java:623)
  at java.awt.Component.dispatchEvent (Component.java:2339)
  at java.awt.EventQueue.dispatchEvent (EventQueue.java:474)
  at java.awt.EventDispatchThread.run (EventDispatchThread.java:75)


Regards,

Dave