问题描述
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,我在模型中有一个带有3列的QTreeView
。我正在根据列表中的缩进遍历一个列表以重构树(在每个深度级别的行的开头使用“ ==”)来表示树的深度。
列表中的每一行用字符串“ |||”分隔给定行中三个项目的文本(我计划在某个时候实现JSON序列化)。
当我在“ |||”上分割行文本时,将产生3个字符串。如果第二个或第三个是空白字符串,则这意味着不应将此项目添加到模型中,即在树视图中应该仅看到树节点,而其其余行中不应包含任何项目(即无效索引) )。
...但是,我发现即使我仅插入1个项目(而不是3个项目的列表),也有时会在QTreeView
模型的行中创建3个项目。并且,即使刚刚插入一项(在col0中),上述检查行中的index.isValid()
始终返回True
。在这种情况下,将col1和col2的data_at_coord
打印为“无”。
因此,在显示的视图中,我可以单击col1或col2作为执行此操作的行,并找到一个空白的可编辑项,然后在检查中发现它们是有效索引。它们不应该是:我的意图是在col1和col2中仅在col0中没有项目的地方添加新行。
当我运行上面的MRE时,“罗马”行的行为应得到:您可以尝试单击col1和col2,但是什么也没有发生。 但是“德国”行的行为似乎很奇怪:当我单击col1或col2时,我发现自己正在编辑一个空白字符串。
注意,如果实际上您使用的是new_model.appendRow
而不是item.appendRow
,则结果有所不同:
- 树构建算法无法正常运行
- “罗马”行现在也无法执行“应做”,而col1和col2是可编辑的空白字符串。
解决方法
问题不是由appendRow方法引起的,而是由未记录的行为引起的。似乎在使用树类型模型时,除了没有子节点的节点会产生此意外行为之外,所有节点始终具有相同的列数。一种解决方法是在文本项中创建带有Qt :: NoItemFlags标志的QStandardItem,以使用户无法与其交互:
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())