Add a method to change the parent of a layout. Make isEmpty() non-virtual, and instead always equal to (count()==0). Add invalidate() method which is used like the method of the same name in QLayout to invalidate cached information in the layout.

svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=706937

widgets/layout.cpp

@@ -21,6 +21,9 @@
 #include <math.h>
 
 #include <QtCore/QList>
+#include <QtDebug>
+
+#include "widget.h"
 
 namespace Plasma
 {
@@ -52,6 +55,10 @@ Layout::Layout(LayoutItem *parent)
 {
 }
 
+void Layout::setParent(LayoutItem *parent) {
+    d->parent = parent;
+}
+
 Layout::~Layout()
 {
     if (parent()) {
@@ -60,11 +67,41 @@ Layout::~Layout()
     delete d;
 }
 
+bool Layout::isEmpty() const 
+{
+    return count() == 0;
+}
+
 void Layout::update()
 {
-    // this will force an update
+
-    setGeometry( parent()->geometry() );
+    setGeometry(geometry());
+
 }
+void Layout::invalidate()
+{
+    //qDebug() << "Layout update"; 
+    LayoutItem *item = parent(); 
+    while ( item ) { 
+        //qDebug() << "Looking at item " << item;
+        Widget *widget = dynamic_cast<Widget*>(item);
+        if ( widget ) {
+            //qDebug() << "Parent widget found and invalidated";
+            widget->updateGeometry();
+            break;
+        }
+        else {
+            Layout *layout = dynamic_cast<Layout*>(item);
+            if ( layout ) {
+                item = layout->parent();
+      //          qDebug() << "Item is a layout";
+            }
+            else
+                item = 0;
+        }
+    }
+}
+
 
 LayoutAnimator* Layout::animator() const
 {

widgets/layout.h

@@ -78,6 +78,11 @@ class PLASMA_EXPORT Layout : public LayoutItem
          */
 		LayoutItem *parent() const;
 
+        /**
+         * Sets the parent of this layout.
+         */
+        void setParent(LayoutItem *parent);
+
         /**
          * Returns the number of elements of this Layout.
          */
@@ -86,7 +91,7 @@ class PLASMA_EXPORT Layout : public LayoutItem
         /**
          * Returns true if this Layout contains no elements, false otherwise.
          */
-		virtual bool isEmpty() const = 0;
+		bool isEmpty() const;
 
         /**
          * Adds a Item to this Layout.
@@ -143,6 +148,10 @@ class PLASMA_EXPORT Layout : public LayoutItem
          * implementation allows unlimited resizing.
          */
         virtual QSizeF maximumSize() const;      
+
+        /** TODO Document me */
+        void invalidate(); 
+
 	private:
 		class Private;
 		Private *const d;