在继承QAbstrctitemModel时,使用Lists作为QModelIndex中的internalPointer,PyQt

Question

我正在尝试在Python中用QAbstractItemModel包装List,以允许我使用PyQt附带的GUI优点将列表视为树.确切地说,我正在使用PyQt5和Python 3.3.

我试图显式生成列表项的指针,但后来很难识别父项.我没有分配它们,我不确定在执行createIndex时PyQt是如何分配它们的.然后我决定重写代码以明确地识别使用索引(行值)访问的项目,例如给定嵌套列表["A",["a",[1,2,3]],"B", "C",["b",[4,5,6],"d"]]然后我可以使用[4,1,1]指向5,然后使用相同的列表减去最后一项来检索父项,[4,1].

我的问题是这个.当我从行值使用列表生成时,CREATEINDEX方法崩溃代码.我的最小破损示例(MBE)如下.在其中取消注释两行"return self.createIndex(row,col,ptr)"以查看我描述的分解.

from PyQt5.QtGui     import QFont, QColor
from PyQt5.QtCore    import QAbstractItemModel, QModelIndex, Qt, QAbstractListModel, QAbstractTableModel, QSize, QVariant
from PyQt5.QtWidgets import QApplication, QTreeView, QTableView, QListView

class NodeTree(QAbstractItemModel) :
 def __init__(self,parent,data) :
  super(NodeTree,self).__init__(parent)
  self.data   = data

 def rowCount(self, parent = QModelIndex()) :
  # int rowCount (self, QModelIndex parent = QModelIndex())
  if parent.isValid() :
   data = self.data
   for idx in parent.internalPointer() :
    data = data[idx]
   return len(data)
  else : 
   return len(self.data)  

 def columnCount(self, parent = QModelIndex()) :
  # int columnCount (self, QModelIndex parent = QModelIndex())
  return 1

 def data(self, index = QModelIndex(), role = None) :  
  # QVariant data (self, QModelIndex index, int role = Qt.DisplayRole)
  if role == 0 :
   if index.isValid() :
    return str(index.internalPointer())
   else : 
    return "No Data" 
  return None

 def index(self,row,col, parent = QModelIndex()):
  # QModelIndex index (self, int row, int column, QModelIndex parent = QModelIndex())
  # QModelIndex createIndex (self, int arow, int acolumn, int aid)
  # QModelIndex createIndex (self, int arow, int acolumn, object adata = 0)
  if parent.isValid() :
   ptr = [parent.internalPointer(),row]
#     return self.createIndex(row,col,ptr)
   return QModelIndex()
  else :
   ptr = [row]
#    return self.createIndex(row,col,ptr)
   return QModelIndex()
  return QModelIndex() 

 def parent(self, child = QModelIndex()): 
  # QObject parent (self)
  if child.isValid() :
   print(child.internalPointer())
  return QModelIndex()

if __name__ == "__main__" :
 # http://blog.mathieu-leplatre.info/filesystem-watch-with-pyqt4.html
 import sys

 app = QApplication(sys.argv)
 TreeView  = QTreeView()
 TreeModel = NodeTree(TreeView, [['A',['a',1]],['C','D'],['E','F']])
 TreeView.setModel(TreeModel)
 TreeView.show()
 app.exec_()

我不明白的是如何在CREATEINDEX中创建QModelIndex,以及为什么它会在INDEX方法中动态生成的列表崩溃.对我来说,INTERNALPOINTER应该在电话之间保留,并且传递一个列表应该没问题.

令我困惑的另一件事是调用父和索引的时间和原因.据我所知,索引遍历树,父进程遍历.所以对INDEX的调用在父项(row,col)中标识父项的子项,而PARENT是子项并确定父项.是参考内部指针完成的吗？如果是这样,为什么QmodelIndex会维护它自己的PARENT方法.似乎Qt维护它自己的内部树,它根据索引和父级之间的调用建立项之间的层次结构.也就是说,我的模型和展出的树总是有两棵树.

Answer 1

我想你的帮助是从这个输入列表中获得的

[['A',['a',1]],['C','D'],['E','F']]

以下输出

您的代码主要在这些方面失败(在我看来):

• 您不会拆分树模型和树项数据,这会产生一些混淆.
• 与第一点相关,您可以根据数据计算一些属性,而不仅仅基于Qt ModelIndex.

在下面的代码中,我尝试尽可能接近与TreeView组件的qt示例代码(C++)的一对一关系(如此处所示)

from PyQt5.QtCore    import (
   QAbstractItemModel, 
   QModelIndex, 
   Qt, 
   QVariant
)

from PyQt5.QtWidgets import QApplication, QTreeView

class TreeItem(object):
    def __init__(self, content, parentItem):
        self.content = content
        self.parentItem = parentItem
        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 1

    def data(self, column):
        if self.content != None and column == 0:
           return QVariant(self.content)

        return QVariant()

    def parent(self):
        return self.parentItem

    def row(self):
        if self.parentItem:
            return self.parentItem.childItems.index(self)
        return 0

class NodeTree(QAbstractItemModel):
   def __init__(self,parent,data) :
      super(NodeTree,self).__init__(parent)
      self.rootItem = TreeItem(None, None)
      self.parents = {0 : self.rootItem}
      self.setupModelData(self.rootItem, data)

   def setupModelData(self, root, data):
      for el in data:
         if isinstance(el, list):
            item = TreeItem("Node", root)
            self.setupModelData(item, el)
         else:
            item = TreeItem(el, root)
         root.appendChild(item)

   def rowCount(self, parent = QModelIndex()):
      if parent.column() > 0:
         return 0
      if not parent.isValid():
         p_Item = self.rootItem
      else:
         p_Item = parent.internalPointer()
      return p_Item.childCount() 

   def columnCount(self, parent = QModelIndex()):
      return 1

   def data(self, index, role):
       if not index.isValid():
           return QVariant()

       item = index.internalPointer()
       if role == Qt.DisplayRole:
           return item.data(index.column())
       if role == Qt.UserRole:
           if item:
               return item.content

       return QVariant()

   def headerData(self, column, orientation, role):
       if (orientation == Qt.Horizontal and
                role == Qt.DisplayRole):
           return QVariant("Content")

       return QVariant()

   def index(self, row, column, parent):
       if not self.hasIndex(row, column, parent):
          return 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 QModelIndex()

   def parent(self, index):
       if not index.isValid():
          return QModelIndex()

       childItem = index.internalPointer()
       if not childItem:
          return QModelIndex()

       parentItem = childItem.parent()

       if parentItem == self.rootItem:
          return QModelIndex()

       return self.createIndex(parentItem.row(), 0, parentItem)

if __name__ == "__main__" :
   # http://blog.mathieu-leplatre.info/filesystem-watch-with-pyqt4.html
   import sys

   app = QApplication(sys.argv)
   TreeView  = QTreeView()
   TreeModel = NodeTree(TreeView, [['A',['a',1]],['C','D'],['E','F']])
   TreeView.setModel(TreeModel)
   TreeView.show()
   app.exec_()

我希望这可以帮到你.