QAbstractItemModel：QTreeView令人討厭的支線

Question

我做了一個簡約的子類QAbstractItemModel。它的工作原理，但在QTreeView有一個奇怪的分支線，不應該出現在這裏（因爲[傳感器陣列]部分後沒有更多的項目）。你不能告訴我，我做錯了什麼，以及如何解決它？

這裏是我的代碼：

import os, sys 

from PyQt5 import QtCore, QtGui, QtWidgets 

import treelib 


class BlockHierarchyNode(object): 
    def __init__(self, icon_path=None, name="", description="", is_category=False): 
     if icon_path is not None: 
      self._icon = QtGui.QPixmap(icon_path) 
      if self._icon.size() == QtCore.QSize(): # zero size (loading error) 
       assert False 

     else: 
      self._icon = None 

     self._is_category = bool(is_category) 
     self._name = str(name) 
     self._description = str(description) 

    @property 
    def icon(self): 
     return self._icon 

    @property 
    def is_category(self): 
     return self._is_category 

    @property 
    def name(self): 
     return self._name 

    @property 
    def description(self): 
     return self._description 

    def __str__(self): 
     if self.is_category: 
      return "[%s]" % self.name 
     else: 
      return self.name 


class AvailableBlocksModel(QtCore.QAbstractItemModel): 
    def __init__(self, data_tree, parent=None): 
     super(AvailableBlocksModel, self).__init__(parent) 

     self._tree = data_tree 
     assert isinstance(data_tree, treelib.Tree) 

    def columnCount(self, parent_index): 
     if parent_index.isValid(): 
      return 1 
     else: 
      return 1 

    def rowCount(self, parent_index): 
     if parent_index.isValid(): 
      return len(self._tree.children(parent_index.internalPointer().identifier)) 
     else: # root node 
      return 1 

    def data(self, index, role): 

     if not index.isValid(): 
      return None 

     if role == QtCore.Qt.DisplayRole: 
      return str(index.internalPointer().data) 
     elif role == QtCore.Qt.DecorationRole: 
      icon = index.internalPointer().data.icon 
      if icon is not None: 
       return icon 

     return None 

    def index(self, row, column, parent=QtCore.QModelIndex()): 
     if not self.hasIndex(row, column, parent): 
      return QtCore.QModelIndex() 
     if parent.isValid(): 
      parent_node = parent.internalPointer() 
      children = self._tree.children(parent_node.identifier) 
      return self.createIndex(row, column, children[row]) 
     else: 
      return self.createIndex(row, column, self._tree.nodes[self._tree.root]) 

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

     child_item = index.internalPointer() 
     parent_item = self._tree.parent(child_item.identifier) 

     if parent_item is None: 
      return QtCore.QModelIndex() 

     parent_row = 0 
     siblings = self._tree.siblings(parent_item.identifier) 
     for i, elm in enumerate(siblings): 
      if elm == parent_item: 
       parent_row = i 

     return self.createIndex(parent_row, 0, parent_item) 


class MegaTree(treelib.Tree): 
    def add_block_node(self, data_block, identifier=None, parent_node=None): 
     id = identifier if identifier is not None else data_block.name 
     if parent_node is None: 
      return self.create_node(str(data_block), id, data=data_block) 
     else: 
      return self.create_node(str(data_block), id, data=data_block, parent=parent_node.identifier) 

    @staticmethod 
    def create_demo_tree(): 
     tree = MegaTree() 
     root_data = BlockHierarchyNode(name="All blocks", is_category=True) 
     root_node = tree.add_block_node(root_data, "root") # root node 


     waveforms_data = BlockHierarchyNode(name="Waveforms", is_category=True) 
     waveforms_node = tree.add_block_node(waveforms_data, parent_node=root_node) 

     rect_waveform_data = BlockHierarchyNode(name="Rectangular waveform", is_category=False) 
     rect_waveform_node = tree.add_block_node(rect_waveform_data, parent_node=waveforms_node) 

     lfm_waveform_data = BlockHierarchyNode(name="LFM waveform", is_category=False) 
     lfm_waveform_node = tree.add_block_node(lfm_waveform_data, parent_node=waveforms_node) 

     phasecoded_waveform_data = BlockHierarchyNode(name="Phase coded waveform", is_category=False) 
     phasecoded_waveform_node = tree.add_block_node(phasecoded_waveform_data, parent_node=waveforms_node) 


     sensor_array_data = BlockHierarchyNode(name="Sensor arrays", is_category=True) 
     sensor_array_node = tree.add_block_node(sensor_array_data, parent_node=root_node) 

     ura_data = BlockHierarchyNode(name="URA", is_category=False) 
     ura_node = tree.add_block_node(ura_data, parent_node=sensor_array_node) 

     ula_data = BlockHierarchyNode(name="ULA", is_category=False) 
     ula_node = tree.add_block_node(ula_data, parent_node=sensor_array_node) 

     return tree 


if __name__ == "__main__": 
    app = QtWidgets.QApplication(sys.argv) 

    model = AvailableBlocksModel(MegaTree.create_demo_tree()) 

    view = QtWidgets.QTreeView() 

    view.setModel(model) 
    view.expandAll() 
    view.show() 

    sys.exit(app.exec_()) 

Answer 1

哦，我只是忘記了Tree類的treelib的siblings方法給出了一個節點的嚴格的兄弟姐妹（不含在節點本身列表）。所以，在parent方法及其一行是始終爲0 =（

現在的方法是在這裏：

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

    child_item = index.internalPointer() 
    parent_item = self._tree.parent(child_item.identifier) 

    if parent_item is None: 
     return QtCore.QModelIndex() 

    if parent_item.is_root(): 
     parent_row = 0 
    else: 
     siblings = self._tree.children(parent_item.bpointer) 
     for i, elm in enumerate(siblings): 
      if elm == parent_item: 
       parent_row = i