Member Avatar for annndrey

Hello! I've got a question about implementation of a standart tree model for TreeView.

I have a response from database that lools like

[
[A, [a,b,c]],
[B,[a,b,c]],
.
.
.
[N,[a,b,c]]
]

And I want to pass it through treemodel to treeview, for in GUI it looks like that:

A
|
+---a
+---b
+---c
|
B
+
|
+---a
+---b
+---c

I've took a look at example, that comes with PyQT4, but in that example they retrieve data from a text file, where tree structure is marked by tabs. and I cannot realize how I can modify this standart example for it works with my data...

I'll be thankful for any help...

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  • 4 Replies
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  • 4 Years Discussion Span
  • Latest Post Latest Post by vegaseat

Dani AI

Generated

If your data come back from the DB as pairs like ("A", ["a","b","c"]), you do not need to parse tabs at all. Build the same internal tree the Qt example uses, but fill each TreeItem with a list of column values. The key fixes for multi-column support are:

  • TreeItem.data(column) must return a single column, not the whole list.
  • Model.data(index, role) should return the item’s column value for index.column().
  • When editing, return True from setData and emit dataChanged for that index.
  • In parent(), always create the parent index with column 0 so the hierarchy is anchored in column 0 (rows in other columns are siblings of the same item, not separate parents).

A tiny sketch to populate a two-column tree (e.g., Name, Kind) from your DB response:

# db = [("A", ["a","b","c"]), ("B", ["a","b"])]

class Node:
    def __init__(self, cols, parent=None):
        self.cols = list(cols)     # e.g., ["A", "group"]
        self.parent = parent
        self.children = []

root = Node(["Name", "Kind"])
for group, members in db:
    parent = Node([group, "group"], root); root.children.append(parent)
    for m in members:
        parent.children.append(Node([m, "leaf"], parent))

Then make your model delegate to this structure:

  • columnCount(parent): return node.column_count (usually len(node.cols)).
  • data(index, role): return node.cols[index.column()] for DisplayRole/EditRole.
  • rowCount(parent): return node.child_count (and 0 when parent.column() > 0).
  • parent(index): return an index to the item’s parent at column 0.

your current TreeItem.data returns the entire itemData, which blocks multi-column. Change it to index by column. Also ensure setData emits dataChanged.

setupModelData is just the one-time loader that converts your source structure into TreeItem nodes. The stack in the OP tracks the current parent; for two levels, a simple loop (as above) is easier, but the idea is the same: create a node, attach it to the current parent, then attach its children.

Member Avatar for annndrey

Finally I've fount a solution!

(Idea taken from here: http://www.mail-archive.com/pyqt@riverbankcomputing.com/msg19400.html)

class TreeModel(QtCore.QAbstractItemModel):  
        def __init__(self, data, parent=None):  
            super(TreeModel, self).__init__(parent)  
            self.parents=[]  
            self.dbdata = data  
            self.rootItem = TreeItem([u"NameOfColumn"])  
            self.setupModelData(self.dbdata, self.rootItem)  
      
        def setData(self, index, value, role):  
           if index.isValid() and role == QtCore.Qt.EditRole:  
     
               prev_value = self.getValue(index)  
     
               item = index.internalPointer()  
     
               item.setData(unicode(value.toString()))  
     
               return True  
           else:  
               return False  
     
       def removeRows(self, position=0, count=1,  parent=QtCore.QModelIndex()):  
     
           node = self.nodeFromIndex(parent)  
           self.beginRemoveRows(parent, position, position + count - 1)  
           node.childItems.pop(position)  
           self.endRemoveRows()  
     
       def nodeFromIndex(self, index):  
           if index.isValid():  
               return index.internalPointer()  
           else:  
               return self.rootItem  
     
       def getValue(self, index):  
           item = index.internalPointer()  
           return item.data(index.column())  
     
       def columnCount(self, parent):  
           if parent.isValid():  
               return parent.internalPointer().columnCount()  
           else:  
               return self.rootItem.columnCount()  
     
       def data(self, index, role):  
           if not index.isValid():  
               return None  
           if role != QtCore.Qt.DisplayRole:  
               return None  
     
           item = index.internalPointer()  
           return QtCore.QVariant(item.data(index.column()))  
     
      def flags(self, index):  
           if not index.isValid():  
               return QtCore.Qt.NoItemFlags  
     
           return QtCore.Qt.ItemIsEnabled | QtCore.Qt.ItemIsSelectable | QtCore.Qt.ItemIsEditable  
     
       def headerData(self, section, orientation, role):  
           if orientation == QtCore.Qt.Horizontal and role == QtCore.Qt.DisplayRole:  
               return QtCore.QVariant(self.rootItem.data(section)[0])  
     
           return None  
     
       def index(self, row, column, parent):  
     
           if row < 0 or column < 0 or row >= self.rowCount(parent) or column >= self.columnCount(parent):  
               return QtCore.QModelIndex()  
     
           if not parent.isValid():  
               parentItem = self.rootItem  
           else:  
               parentItem = parent.internalPointer()  
     
           childItem = parentItem.child(row)  
           if childItem:  
               return self.createIndex(row, column, childItem)  
           else:  
               return QtCore.QModelIndex()  
     
       def parent(self, index):  
           if not index.isValid():  
               return QtCore.QModelIndex()  
     
           childItem = index.internalPointer()  
           parentItem = childItem.parent()  
     
           if parentItem == self.rootItem:  
               return QtCore.QModelIndex()  
     
           return self.createIndex(parentItem.row(), 0, parentItem)  
     
       def rowCount(self, parent):  
           if parent.column() > 0:  
               return 0  
     
           if not parent.isValid():  
               parentItem = self.rootItem  
           else:  
               parentItem = parent.internalPointer()  
    
           return parentItem.childCount()  
     
       def setupModelData(self, lines, parent):  
           ind = []  
           self.parents.append(parent)  
           ind.append(0)  
           col_numb=parent.columnCount()  
           numb = 0  
     
           for line in lines:  
               numb+=1  
               lineData=line[0]  
               self.parents[-1].appendChild(TreeItem(lineData, self.parents[-1]))  
     
               columnData = line[1]  
    
               self.parents.append(self.parents[-1].child(self.parents[-1].childCount() - 1))  
    
               for j in columnData:  
                    self.parents[-1].appendChild(TreeItem(j, self.parents[-1]))  
               if len(self.parents) > 0:  
                    self.parents.pop()  
    
  class TreeItem(object):  
      def __init__(self, data, parent=None):  
          self.parentItem = parent  
          self.itemData = data  
          self.childItems = []  
    
      def appendChild(self, item):  
          self.childItems.append(item)  
    
      def child(self, row):  
          return self.childItems[row]  
    
      def childCount(self):  
          return len(self.childItems)  
    
      def columnCount(self):  
          return len(self.itemData)  
    
      def data(self, column):  
          try:  
              return self.itemData  
   
          except IndexError:  
              return None  
    
      def parent(self):  
          return self.parentItem  
    
      def row(self):  
          if self.parentItem:  
              return self.parentItem.childItems.index(self)  
    
          return 0  
      def setData(self, data):  
          self.itemData = data
Edited by annndrey because: n/a
Member Avatar for annndrey

Now it works but I still don't know how to add a support for several columns in this model...

Member Avatar for Odyssey2001

Could someone explain to me how setupModelData works??

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