wxQt: Make wxListCtrl::SetColumnWidth() conformant to documentation

Also update the listctrl sample to show it's effect on the second column
wxLIST_AUTOSIZE (Ctrl+R) to resize the column to content
wxLIST_AUTOSIZE_USEHEADER (Ctrl+Shift+R) to resize it to header section

interface/wx/listctrl.h

@@ -1077,7 +1077,7 @@ public:
         @c wxLIST_AUTOSIZE will resize the column to the length of its longest item.
 
         @c wxLIST_AUTOSIZE_USEHEADER will resize the column to the length of the
-        header (Win32) or 80 pixels (other platforms).
+        header (wxMSW and wxQt) or 80 pixels (other platforms).
 
         In small or normal icon view, @a col must be -1, and the column width is set
         for all columns.

samples/listctrl/listtest.cpp

@@ -151,6 +151,8 @@ wxBEGIN_EVENT_TABLE(MyFrame, wxFrame)
     EVT_MENU(LIST_TOGGLE_HEADER, MyFrame::OnToggleHeader)
     EVT_MENU(LIST_TOGGLE_BELL, MyFrame::OnToggleBell)
     EVT_MENU(LIST_CHECKVISIBILITY, MyFrame::OnCheckVisibility)
+    EVT_MENU(LIST_AUTOSIZE, MyFrame::OnAutoResize)
+    EVT_MENU(LIST_AUTOSIZE_USEHEADER, MyFrame::OnAutoResize)
     EVT_MENU(LIST_FIND, MyFrame::OnFind)
     EVT_MENU(LIST_TOGGLE_CHECKBOX, MyFrame::OnToggleItemCheckBox)
     EVT_MENU(LIST_GET_CHECKBOX, MyFrame::OnGetItemCheckBox)
@@ -260,6 +262,9 @@ MyFrame::MyFrame(const wxString& title)
     menuList->AppendCheckItem(LIST_TOGGLE_BELL, "Toggle &bell on no match");
     menuList->Append( LIST_CHECKVISIBILITY, "Check if lines 2 and 9 are visible" );
     menuList->AppendSeparator();
+    menuList->Append( LIST_AUTOSIZE, "Auto resize column 2\tCtrl-R" );
+    menuList->Append( LIST_AUTOSIZE_USEHEADER, "Auto resize column 2 (use header)\tCtrl-Shift-R" );
+    menuList->AppendSeparator();
     menuList->AppendCheckItem(LIST_TOGGLE_CHECKBOXES,
                               "&Enable Checkboxes");
     menuList->Check(LIST_TOGGLE_CHECKBOXES, true);
@@ -379,6 +384,20 @@ void MyFrame::OnCheckVisibility(wxCommandEvent& WXUNUSED(event))
         wxLogMessage( "Line 9 is not visible" );
 }
 
+void MyFrame::OnAutoResize(wxCommandEvent& event)
+{
+    if ( event.GetId() == LIST_AUTOSIZE )
+    {
+        wxLogMessage( "Column 2 resized to content" );
+        m_listCtrl->SetColumnWidth(1, wxLIST_AUTOSIZE);
+    }
+    else
+    {
+        wxLogMessage( "Column 2 resized to header" );
+        m_listCtrl->SetColumnWidth(1, wxLIST_AUTOSIZE_USEHEADER);
+    }
+}
+
 void MyFrame::OnGoTo(wxCommandEvent& WXUNUSED(event))
 {
     if ( m_listCtrl->IsEmpty() )

samples/listctrl/listtest.h

@@ -117,6 +117,7 @@ protected:
     void OnVirtualView(wxCommandEvent& event);
     void OnSmallVirtualView(wxCommandEvent& event);
     void OnCheckVisibility(wxCommandEvent& event);
+    void OnAutoResize(wxCommandEvent& event);
     void OnSetItemsCount(wxCommandEvent& event);
 
 
@@ -243,5 +244,7 @@ enum
     LIST_THAW,
     LIST_TOGGLE_LINES,
     LIST_CHECKVISIBILITY,
+    LIST_AUTOSIZE,
+    LIST_AUTOSIZE_USEHEADER,
     LIST_CTRL                   = 1000
 };

src/qt/listctrl.cpp

@@ -669,6 +669,8 @@ public:
 
         endInsertColumns();
 
+        m_listCtrl->SetColumnWidth(newColumnIndex, info.m_width);
+
         return true;
     }
 
@@ -1156,13 +1158,42 @@ int wxListCtrl::GetColumnWidth(int col) const
 
 bool wxListCtrl::SetColumnWidth(int col, int width)
 {
-    if ( width < 0 )
+    const auto header = m_qtTreeWidget->header();
+
+    if ( header &&
+         col == GetColumnIndexFromOrder(col) &&
+         col == GetColumnCount() - 1 )
     {
-        m_qtTreeWidget->resizeColumnToContents(width);
-        return true;
+        // Always stretch the last section if _with_ is either
+        // wxLIST_AUTOSIZE or wxLIST_AUTOSIZE_USEHEADER
+        header->setStretchLastSection( width < 0 );
     }
 
-    m_qtTreeWidget->setColumnWidth(col, width);
+    if ( width >= 0 )
+        m_qtTreeWidget->setColumnWidth(col, width);
+    else
+    {
+        if ( width == wxLIST_AUTOSIZE_USEHEADER )
+        {
+            const auto header = m_qtTreeWidget->header();
+            const QHeaderView::ResizeMode oldResizeMode = header->sectionResizeMode(col);
+
+            header->setSectionResizeMode(col, QHeaderView::ResizeToContents);
+            header->resizeSection(col, header->defaultSectionSize()); // passing any value > 0 is ok
+            header->setSectionResizeMode(col, oldResizeMode);
+        }
+        else // wxLIST_AUTOSIZE
+        {
+            // Temporarily hide the header if it's shown as we don't want the header section
+            // to be considered by resizeColumnToContents() because it's size will be honored
+            // if it's larger than the column content.
+            const bool wasHidden = m_qtTreeWidget->isHeaderHidden();
+            m_qtTreeWidget->setHeaderHidden(true);
+            m_qtTreeWidget->resizeColumnToContents(col);
+            m_qtTreeWidget->setHeaderHidden(wasHidden);
+        }
+     }
+
     return true;
 }