QStandardItemModel添加仅包含一项的行

Question

MRE：

from PyQt5.QtWidgets import *
from PyQt5.QtGui import QStandardItemModel, QStandardItem
from PyQt5 import QtCore
import PyQt5
import sys, types

class OrgItemModel( QStandardItemModel ):
    def __init__( self, tree_view ):
        super().__init__()
        self.tree_view = tree_view
        self.setHorizontalHeaderLabels( [ 'Tasks', 'Due date', 'Notes' ] )

def configure( tree_view, main_window ):
    tree_view.setModel( OrgItemModel( tree_view ) )
    def load_from_list( self ):
        new_model = OrgItemModel( self )
        root_item = new_model.invisibleRootItem()
        lines = [
            'Europe ||| 2020-10-26 ||| some notes',
            '==France ||| 2020-10-27 ||| some France notes',
            '====Paris ||| --- ||| blah blah',
            '==Germany |||  ||| ',
            '==Italy ||| 2020-10-28 ||| some Italy notes',
            '====Rome |||  ||| ',
            '==Ireland ||| 2020-10-30 ||| blah blah',
        ]
        new_model.ptr = 0
        def read_child_rows( item, depth = 0 ):        
            while new_model.ptr < len( lines ):
                line = lines[ new_model.ptr ]
                new_model.ptr += 1  
                n_equals = len( line ) - len( line.lstrip('=') )
                item_text = line.lstrip('=').strip()
                read_depth = n_equals / 2
                if read_depth == depth:
                    item_col0 = QStandardItem( item_text )
                    # split up the line by the substring ' ||| '
                    item_texts = line.split( ' ||| ' )
                    text_col0 = item_texts[ 0 ].lstrip( '=' ).strip()
                    text_col1 = item_texts[ 1 ].strip()
                    text_col2 = item_texts[ 2 ].strip()
                    item_col0 = QStandardItem( text_col0 )    
                    if text_col1 == '':
                        print( f'col1 blank for {text_col0}')
                        item_col1 = None
                    else:
                        item_col1 = QStandardItem( text_col1 )    
                    if text_col2 == '':
                        print( f'col2 blank for {text_col0}')
                        item_col2 = None
                    else:
                        item_col2 = QStandardItem( text_col2 )    
                    if item_col1 == None or item_col2 == None:
                        print( 'inserting just first item...')
                        item.appendRow( item_col0 )
                    else:  
                        item.appendRow( [ item_col0, item_col1, item_col2 ] )
                    # NB here I'm trying to examine the row which has just been added.
                    # But this is now not giving the right value for rowCount: this
                    # may be because previously I was experimenting with new_model.appendRow 
                    # rather than item.appendRow: the central problem still arises...
                    print( f'row count {new_model.rowCount()}')    
                    for j_col in range( 3 ):
                        index = new_model.index( new_model.rowCount() - 1, j_col )
                        data_at_coord = new_model.data( index )
                        print( data_at_coord, index.isValid() )
                else:
                    new_model.ptr -= 1
                    if read_depth > depth:
                        read_child_rows( item_col0, depth + 1 )
                    else:
                        break
        read_child_rows( root_item )
        del new_model.ptr
        self.setModel( new_model )
        self.expandAll()
        self.resizeColumnToContents( 0 )
    tree_view.load_from_list = types.MethodType( load_from_list, tree_view )

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.resize(1100, 580)
        self.centralwidget = QWidget(MainWindow)
        self.treeView = QTreeView(self.centralwidget)
        self.treeView.setGeometry(QtCore.QRect(20, 20, 1000, 320 ))
        MainWindow.setCentralWidget(self.centralwidget)

class MyWindow( QMainWindow):
    def __init__(self):
        super( MyWindow, self ).__init__()
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)
        configure( self.ui.treeView, self )
        self.ui.treeView.load_from_list()

app = QApplication([])
application = MyWindow()
application.show()

sys.exit(app.exec())

我对QStandardItemModel方法insertRow和appendRow感到困惑。目前，我有一个模型中有3列的QTreeView。我正在遍历一个列表，根据列表中的缩进（在每一深度级别的行开始处使用“==”）来表示树的深度，重新构建树

列表中的每一行用字符串“| | | |”（我计划在某个时候实现JSON序列化）分隔给定行上三个项目的文本

当我在“| | |”上拆分行文本时，将生成3个字符串。如果第二个或第三个是空白字符串，这意味着不应将此项添加到模型中，即在树视图中，只应看到树节点，其行的其余部分不应包含任何项（即无效索引）。 ... 但是我发现，即使我只插入1个项目（而不是3个项目的列表），在QTreeView的模型中的行中（有时）也会创建3个项目。上面检查行中的index.isValid()总是返回True，即使它只是插入了一项（在col0中）。在这种情况下，col1和col2的data_at_coord被打印为“无”

因此，在显示的视图中，我可以单击col1或col2，找到一个空白的可编辑项，检查后发现这些是有效的索引。它们不应该是这样的：我的意图是添加一个新行，其中在col1和col2中没有项目，只有在col0中

当我运行上面的MRE时，“Rome”行的行为应该是这样的：您可以尝试单击col1和col2，但什么也没有发生但“德国”行的行为似乎很奇怪：当我单击col1或col2时，我发现我正在编辑一个空白字符串

注意：如果事实上您使用了new_model.appendRow而不是item.appendRow，则结果会有所不同：

1. 树构造算法无法正常工作，而且
2. “Rome”行现在也无法执行“应该”的操作，col1和col2是可编辑的空白字符串

Answer 1

问题不是由appendRow方法引起的，而是由未记录的行为引起的。看起来，对于树型模型，除了没有生成此意外行为的子节点的节点外，所有节点的列数始终相同。一种解决方法是在文本项中创建带有Qt:：NoItemFlags标志的QStandardItem，这样用户就无法与它们交互：

import sys

from PyQt5.QtCore import QRect, Qt
from PyQt5.QtGui import QStandardItemModel, QStandardItem
from PyQt5.QtWidgets import QApplication, QMainWindow, QTreeView, QWidget


class OrgItemModel(QStandardItemModel):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setHorizontalHeaderLabels(["Tasks", "Due date", "Notes"])


def configure_from_list(model, lines):
    def get_parent_item(depth):
        parent = model.invisibleRootItem()
        if depth == 0:
            return parent
        for _ in range(depth):
            if parent.hasChildren():
                parent = parent.child(parent.rowCount() - 1)
            else:
                it = QStandardItem()
                it.setFlags(Qt.NoItemFlags)
                parent.appendRow(it)
                parent = it
        return parent

    for line in lines:
        values = line.strip("=")
        depth = (len(line) - len(values)) // 2
        items = []
        for value in values.split("|||"):
            text = value.strip()
            item = QStandardItem()
            if text:
                item.setText(text)
            else:
                item.setFlags(Qt.NoItemFlags)
            items.append(item)
        parent_item = get_parent_item(depth)
        parent_item.appendRow(items)


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.resize(1100, 580)
        self.centralwidget = QWidget(MainWindow)
        self.treeView = QTreeView(self.centralwidget)
        self.treeView.setGeometry(QRect(20, 20, 1000, 320))
        MainWindow.setCentralWidget(self.centralwidget)


class MyWindow(QMainWindow):
    def __init__(self):
        super(MyWindow, self).__init__()
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)

        lines = [
            "Europe ||| 2020-10-26 ||| some notes",
            "==France ||| 2020-10-27 ||| some France notes",
            "====Paris |||  - ||| blah blah",
            "==Germany |||  ||| ",
            "==Italy ||| 2020-10-28 ||| some Italy notes",
            "====Rome |||  ||| ",
            "==Ireland ||| 2020-10-30 ||| blah blah",
        ]
        model = OrgItemModel()
        self.ui.treeView.setModel(model)
        configure_from_list(model, lines)
        self.ui.treeView.expandAll()


app = QApplication(sys.argv)
application = MyWindow()
application.show()
sys.exit(app.exec())