Add virtual wxBookCtrlXmlHandlerBase::DoAddPage()

This will allow customizing the way pages are added to the book control
and will also be used in wxTreebookXmlHandler soon.

include/wx/xrc/xh_bookctrlbase.h

@@ -40,7 +40,6 @@ protected:
     // Return true if we're parsing the book control node itself.
     bool IsInside() const { return m_isInside; }
 
-private:
     // This struct contains the actual page, created by DoCreatePage(), and all
     // its attributes read from wxXmlNode.
     struct PageWithAttrs
@@ -58,6 +57,14 @@ private:
         int bmpId; // index in m_bookImages vector
     };
 
+private:
+    // This function is implemented by just calling AddPage() in the base
+    // class, but can be overridden if something else is needed, as is e.g. the
+    // case for wxTreebookXmlHandler.
+    virtual void
+    DoAddPage(wxBookCtrlBase* book, size_t n, const PageWithAttrs& page);
+
+
     // And this vector contains all the pages created so far.
     wxVector<PageWithAttrs> m_bookPages;
 

src/xrc/xh_bookctrlbase.cpp

@@ -52,6 +52,14 @@ wxBookCtrlXmlHandlerBase::~wxBookCtrlXmlHandlerBase()
     // PageWithAttrs which is not fully declared in the header.
 }
 
+void
+wxBookCtrlXmlHandlerBase::DoAddPage(wxBookCtrlBase* book,
+                                    size_t WXUNUSED(n),
+                                    const PageWithAttrs& page)
+{
+    book->AddPage(page.wnd, page.label, page.selected, page.GetImageId());
+}
+
 void wxBookCtrlXmlHandlerBase::DoCreatePages(wxBookCtrlBase* book)
 {
     bool old_ins = m_isInside;
@@ -74,12 +82,7 @@ void wxBookCtrlXmlHandlerBase::DoCreatePages(wxBookCtrlBase* book)
 
     for ( size_t i = 0; i < m_bookPages.size(); ++i )
     {
-        const PageWithAttrs& currentPage = m_bookPages.at(i);
-
-        book->AddPage(currentPage.wnd,
-                      currentPage.label,
-                      currentPage.selected,
-                      currentPage.GetImageId());
+        DoAddPage(book, i, m_bookPages[i]);
     }
 
     m_bookImages.swap(imagesSave);