treeview中的复选框更新缓慢

Question

我实现了TreeView的cutom模型，让树形视图内有复选框。如果我检查一个父节点，所有的子节点都应该自动检查。这基本上工作，但德是检查父节点和更新子节点之间的时间缺乏。

from PyQt4 import QtCore, QtGui 
import sys 

class Node(object): 
    def __init__(self, name, parent=None, checked=False): 

     self._name = name 
     self._children = [] 
     self._parent = parent 
     self._checked = checked 

     if parent is not None: 
      parent.addChild(self) 

    def addChild(self, child): 
     self._children.append(child) 

    def insertChild(self, position, child): 
     if position < 0 or position > len(self._children): 
      return False 

     self._children.insert(position, child) 
     child._parent = self 
     return True 

    def name(self): 
     return self._name 

    def checked(self): 
     return self._checked 

    def setChecked(self, state): 
     self._checked = state 

     for c in self._children: 
      c.setChecked(state) 

    def child(self, row): 
     return self._children[row] 

    def childCount(self): 
     return len(self._children) 

    def parent(self): 
     return self._parent 

    def row(self): 
     if self._parent is not None: 
      return self._parent._children.index(self) 

class TreeModel(QtCore.QAbstractItemModel): 
    def __init__(self, root, parent=None): 
     super().__init__(parent) 
     self._rootNode = root 

    def rowCount(self, parent): 
     if not parent.isValid(): 
      parentNode = self._rootNode 
     else: 
      parentNode = parent.internalPointer() 

     return parentNode.childCount() 

    def columnCount(self, parent): 
     return 1 

    def data(self, index, role): 
     if not index.isValid(): 
      return None 

     node = index.internalPointer() 

     if role == QtCore.Qt.DisplayRole: 
      if index.column() == 0: 
       return node.name() 
     if role == QtCore.Qt.CheckStateRole: 
      if node.checked(): 
       return QtCore.Qt.Checked 
      else: 
       return QtCore.Qt.Unchecked 

    def setData(self, index, value, role=QtCore.Qt.EditRole): 

     if index.isValid(): 
      if role == QtCore.Qt.CheckStateRole: 
       node = index.internalPointer() 
       node.setChecked(not node.checked()) 
       return True 
     return False 

    def headerData(self, section, orientation, role): 
     if role == QtCore.Qt.DisplayRole: 
      return "Nodes" 

    def flags(self, index): 
     return QtCore.Qt.ItemIsEnabled | QtCore.Qt.ItemIsSelectable| QtCore.Qt.ItemIsUserCheckable 

    def parent(self, index): 
     node = self.getNode(index) 
     parentNode = node.parent() 

     if parentNode == self._rootNode: 
      return QtCore.QModelIndex() 
     return self.createIndex(parentNode.row(), 0, parentNode) 

    def index(self, row, column, parent): 
     parentNode = self.getNode(parent) 
     childItem = parentNode.child(row) 

     if childItem: 
      return self.createIndex(row, column, childItem) 
     else: 
      return QtCore.QModelIndex() 

    def getNode(self, index): 
     if index.isValid(): 
      node = index.internalPointer() 
      if node: 
       return node 

     return self._rootNode 

    def removeRows(self, position, rows, parent=QtCore.QModelIndex()): 

     parentNode = self.getNode(parent) 
     self.beginRemoveRows(parent, position, position + rows - 1) 

     for row in range(rows): 
      success = parentNode.removeChild(position) 

     self.endRemoveRows() 

     return success 

def main_simple(): 
    app = QtGui.QApplication(sys.argv) 

    rootNode = Node("Root") 
    n1 = Node("Node1", rootNode) 
    n2 = Node("Node2", rootNode) 
    n3 = Node("Node3", rootNode) 

    n1_1 = Node("Node1 1", n1) 
    n1_2 = Node("Node1 2", n1) 
    n1_3 = Node("Node1 3", n1) 

    n2_1 = Node("Node2 1", n2) 
    n2_2 = Node("Node2 2", n2) 
    n2_3 = Node("Node2 3", n2) 

    n3_1 = Node("Node3 1", n3) 
    n3_2 = Node("Node3 2", n3) 
    n3_3 = Node("Node3 3", n3) 

    model = TreeModel(rootNode) 

    treeView = QtGui.QTreeView() 
    treeView.show() 
    treeView.setModel(model) 

    sys.exit(app.exec_()) 

if __name__ == '__main__': 
    main_simple() 

我该如何避免这种缺失，使用户界面更流畅？

Answer 1

模型应该在儿童切换时发出dataChanged()信号，以便视图可以立即更新其复选框。根据the documentation,setData也应该发出dataChanged为明确更改的项目。

这应该工作：

def setData(self, index, value, role=QtCore.Qt.EditRole): 
    if index.isValid(): 
     if role == QtCore.Qt.CheckStateRole: 
      node = index.internalPointer() 
      node.setChecked(not node.checked()) 
      self.dataChanged.emit(index, index)    
      self.emitDataChangedForChildren(index) 
      return True 
    return False 

def emitDataChangedForChildren(self, index): 
    count = self.rowCount(index) 
    if count:    
     self.dataChanged.emit(index.child(0, 0), index.child(count-1, 0)) 
     for child in range(count): 
      self.emitDataChangedForChildren(index.child(child, 0))