Re: [PyKDE] MVC Question

Wed, 11 Oct 2006 13:37:47 -0700

Andreas Pakulat wrote: 
On 06.10.06 10:14:17, Matt Chambers wrote:
  
Thanks, that works but then then any branches you have open in the tree view 
closed.   I guess there is no way to maintain
the open/close status of existing branches, and default new ones to open?
    

Hmm, there's API to set the status of a given model index to expanded
(in QTreeView), you'd have to store the indexes that are expanded.

But I think there's no way to have new tree items opened by default,
other than calling setExpanded after inserting new items. 

But generally emitting modelReset() signal means the model's data
completely changed and thus the view drops all information it stores.

If you only want to insert a new node into the model, write functions
that call beginInsertRows/endInsertRows. For more information see the
Qt4 docs, there a chapter about model/view. 

Andreas
Keeping a record of which nodes I have open ending up being slow, and there were other problems with the full
refresh option that turned me off to it.  So I started to look into doing a single full update in the beginning, and
then pulling incremental updates which update my underlying data.

Question now is, I can update the data no problem.  How can I find out what indexes to use when emiting a dataChanged signal
if I update the underlying data in an elementtree ?


class TreeModel( QtCore.QAbstractItemModel ):
   
    def __init__(self, show ):
        QtCore.QAbstractItemModel.__init__(self)
        self.__columns = [ ]   
        self.__data = Data(show,self)
    
    def addColumn(self,label,tag):
        """addColumn(String label, string Tag)
       
        """
        self.__columns.append( [QtCore.QVariant(label),tag] )
  
    def data(self, index, role):

        if role != DISPLAY_ROLE:
            return EMPTY_VARIANT
       
        if not index.isValid():
            return EMPTY_VARIANT

        el = index.internalPointer()
        return QtCore.QVariant( el.get(self.__columns[index.column()][1]) )
   
    def headerData(self, section, orientation, role):
        if orientation == QtCore.Qt.Horizontal and role == DISPLAY_ROLE:
            return self.__columns[section][0]
        return EMPTY_VARIANT

    def index(self, row, column, parent):
        if parent.isValid():
            item = parent.internalPointer()
        else:
            item = self.__data.rootNode
           
        return self.createIndex(row, column, item[row])
   
    def parent(self, index):
        if not index.isValid():
            return EMPTY_INDEX
       
        item,row = self.__data.parentMap[index.internalPointer()]
       
        if id(item) == id(self.__data.rootNode):
            return EMPTY_INDEX
        else:
            return self.createIndex(self.__data.parentMap[item][1],0,item)
   
    def rowCount(self, parent):
        if parent.isValid():
            item = parent.internalPointer()
        else:
            item = self.__data.rootNode
       
        return len(item)
   
    def columnCount(self, parent):
        return len(self.__columns)


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