Hiding decorator on QTreeView in PyQt? - python

I found this code snippet of code on SO:
from PyQt4 import QtCore, QtGui
class Window(QtGui.QWidget):
def __init__(self):
QtGui.QWidget.__init__(self)
self.tree = QtGui.QTreeWidget(self)
self.tree.setHeaderHidden(True)
for index in range(2):
parent = self.addItem(self.tree, 'Item%d' % index)
for color in 'Red Green Blue'.split():
subitem = self.addItem(parent, color)
for letter in 'ABC':
self.addItem(subitem, letter, True, False)
layout = QtGui.QVBoxLayout(self)
layout.addWidget(self.tree)
self.tree.itemChanged.connect(self.handleItemChanged)
def addItem(self, parent, text, checkable=False, expanded=True):
item = QtGui.QTreeWidgetItem(parent, [text])
if checkable:
item.setCheckState(0, QtCore.Qt.Unchecked)
else:
item.setFlags(
item.flags() & ~QtCore.Qt.ItemIsUserCheckable)
item.setExpanded(expanded)
return item
def handleItemChanged(self, item, column):
if item.flags() & QtCore.Qt.ItemIsUserCheckable:
path = self.getTreePath(item)
if item.checkState(0) == QtCore.Qt.Checked:
print('%s: Checked' % path)
else:
print('%s: UnChecked' % path)
def getTreePath(self, item):
path = []
while item is not None:
path.append(str(item.text(0)))
item = item.parent()
return '/'.join(reversed(path))
if __name__ == '__main__':
import sys
app = QtGui.QApplication(sys.argv)
window = Window()
window.setGeometry(500, 300, 250, 450)
window.show()
I wonder, how can i hide the decorators from the result, on all of the items?
I know i can hide with setstylesheet doesn't actually removed the arrows, just hide them, which is counterproductive if you accidentally hide them.
item.setChildPolicy(QTreeWidgetItem.DontShowIndicator) either removes the children, or permanently closes them, because the subitems(children of item) all disappear once i do that, and can't do anything with... Tried to expand too, does't work for me.
Actually in PyQt5, so the answer doesn't need to be in PyQt4.

I got a potential solution from here: How do you disable expansion in QTreeWidget/QTreeView?
Using setStyleSheet, as suggested by eyllanesc, to visibly hide the arrow decorator:
self.tree.setStyleSheet( "QTreeWidget::branch{border-image: url(none.png);}")
and then setting:
self.tree.setItemsExpandable(False)
You can successfully hide and disable the arrow decorators.
Personally, I have used this method when using a QPushButton to control the expanding of the QTreeWidgetItems.
example code
def __init__(self):
self.button = QtWidgets.QPushButton(text="toggle tree item")
self.button.setCheckable = True
self.button.toggled.connect(self.button_clicked)
def button_clicked(self, toggled):
self.tree_widget_item.setExpanded(toggled)

Related

QListWidget checkbox sync with item selection

I encountered a weird problem when I try to set up a QListWidget where I can click the checkbox to select the items. The current code I wrote won't make this pattern consistent. Like the table below.
For example, when I click the "apple" checkbox, I expect "apple" item will be selected, but sometimes orange" will be deselected. Sometimes it worked the way I want, but it is unpredictable. I have been reading pretty much all StackOverflow threads on this problem, but none solves it.
My environment is Mac Big Sur, Python3.7.9, PySide6 6.2.0.
I have an MVE below, could anyone take a look for me? Appreciate it. Stuck here for quite a long time.
from PySide6.QtCore import *
from PySide6.QtGui import *
from PySide6.QtWidgets import *
import sys
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.setWindowTitle("My App")
self.list = QListWidget(self)
self.list.setIconSize(QSize(12, 12))
self.list.setSelectionMode(QAbstractItemView.MultiSelection)
self.list.itemSelectionChanged.connect(
self.on_selection_changed)
self.list.itemChanged.connect(self.on_checkbox_clicked)
# Set the central widget of the Window.
self.setCentralWidget(self.list)
for sheet in ['apple', 'orange', 'banana', 'pearl']:
item = QListWidgetItem(sheet)
self.list.addItem(item)
item.setFlags(item.flags() | Qt.ItemIsUserCheckable)
item.setCheckState(Qt.Unchecked)
def on_checkbox_clicked(self, item):
print(item.text())
print(item.checkState())
if item.checkState() is Qt.CheckState.Checked:
item.setSelected(True)
# self.list.setCurrentItem(
# item, QItemSelectionModel.Select)
print(f'select: {item.text()}')
else:
item.setSelected(False)
# self.list.setCurrentItem(
# item, QItemSelectionModel.Deselect)
print(f'unselect: {item.text()}')
def on_selection_changed(self):
self.list.blockSignals(True)
for index in range(self.list.count()):
item = self.list.item(index)
if item.isSelected():
item.setCheckState(Qt.CheckState.Checked)
elif not item.isSelected():
item.setCheckState(Qt.CheckState.Unchecked)
self.list.blockSignals(False)
app = QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec()
UPDATED:
The first answer is very sophisticated, as I dig more on that there is more to learn. In the end, I found an alternative solution that is much easier to implement. I post the core part for anyone that might need it in the future.
listwidget = QListWidget()
listwidget.setSelectionMode(QAbstractItemView.MultiSelection)
listwidget.itemSelectionChanged.connect(self.on_selection_changed)
def on_selection_changed()
for index in range(listwidget.count()):
item = listwidget.item(index)
if item.isSelected():
item.setIcon(QIcon("path/to/your/check_icon.png"))
else:
item.setIcon(QIcon("path/to/your/uncheck_icon.png"))
From what I understand the OP wants to synchronize that if the user selects an item then it is checked, and vice versa. Considering that, a possible solution is to eliminate the verification that the delegate does on the checkbox rectangle. On the other hand, the user can change the state of the checkbox also using the keyboard, so a possible solution is to use the itemChange signal to update the state of the selection.
class Delegate(QStyledItemDelegate):
def editorEvent(self, event, model, option, index):
last_state = index.data(Qt.ItemDataRole.CheckStateRole)
ret = super().editorEvent(event, model, option, index)
if event.type() in (
QEvent.Type.MouseButtonPress,
QEvent.Type.MouseButtonDblClick,
):
return False
elif event.type() == QEvent.Type.MouseButtonRelease and last_state is not None:
flags = model.flags(index)
if flags & Qt.ItemFlag.ItemIsUserTristate:
state = (last_state + 1) % 3
else:
state = (
Qt.CheckState.Unchecked
if last_state == Qt.CheckState.Checked
else Qt.CheckState.Checked
)
model.setData(index, state, Qt.ItemDataRole.CheckStateRole)
return False
return ret
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.setWindowTitle("My App")
self.listwidget = QListWidget(self)
self.listwidget.setIconSize(QSize(12, 12))
self.listwidget.setSelectionMode(QAbstractItemView.SelectionMode.MultiSelection)
self.setCentralWidget(self.listwidget)
self.listwidget.setItemDelegate(Delegate(self.listwidget))
self.listwidget.itemChanged.connect(self.handle_itemChanged)
for sheet in ["apple", "orange", "banana", "pearl"]:
item = QListWidgetItem(sheet)
self.listwidget.addItem(item)
item.setFlags(item.flags() | Qt.ItemFlag.ItemIsUserCheckable)
item.setCheckState(Qt.CheckState.Unchecked)
def handle_itemChanged(self, item):
item.setSelected(item.checkState() == Qt.CheckState.Checked)

How can I detect when one window occludes another in PyQt5?

I'm using PyQt5 to create an app with multiple main windows. I want to be able to allow the user to save and load window sizes and window positions. That's easy with, e.g., QMainWindow.saveGeometry() and QMainWindow.loadGeometry() or the corresponding .saveState() and .loadState() variants. These work great for position and size, but if the user moves or resizes one window so that it occludes another, I want to also restore this positioning. I don't mind writing my own code to save the info for each window, but I can't see any way to detect the relative Z order of windows. Am I missing it in the docs, or is this not possible?
To see what I mean, try this:
from PyQt5.QtWidgets import QApplication, QMainWindow, QPlainTextEdit
from PyQt5.QtCore import QSettings
from PyQt5.QtGui import QCloseEvent
'''
context: Linux Mint 19.3 Tricia x86_64
Python 3.9
PyQt5 5.15.1
'''
class RememberWin(QMainWindow):
def __init__(self, win_name: str):
super(RememberWin, self).__init__()
self.win_name = win_name
self.setWindowTitle(win_name)
self.can_close = False
def restore_window(self) -> bool:
try:
settings = QSettings("PyQtExamples", "RememberWinTest")
self.restoreGeometry(settings.value(f'{self.win_name} Geometry'))
self.restoreState(settings.value(f'{self.win_name} State'))
return True
except:
return False
def closeEvent(self, event: QCloseEvent):
if not self.can_close:
event.ignore()
else:
settings = QSettings("PyQtExamples", "RememberWinTest")
settings.setValue(f'{self.win_name} Geometry', self.saveGeometry())
settings.setValue(f'{self.win_name} State', self.saveState())
QMainWindow.closeEvent(self, event)
class ControlWindow(RememberWin):
def __init__(self, win_name: str = "ControlWindow"):
super(ControlWindow, self).__init__(win_name=win_name)
self.can_close = True
self.window1 = RememberWin(win_name='WindowOne')
self.window2 = RememberWin(win_name='WindowTwo')
self.text = QPlainTextEdit(self)
s = "Try making Window1 wide enough to cover Window2.\n" \
"Then close this window (auto closes others).\n" \
"Re-run the app and you'll notice that Window2\n" \
"is not on top of Window1 which means that this\n" \
"info isn't getting saved."
self.text.setPlainText(s)
self.setCentralWidget(self.text)
if not self.restore_window():
self.setGeometry(100, 390, 512, 100)
if not self.window1.restore_window():
self.window1.setGeometry(100, 100, 512, 384)
if not self.window2.restore_window():
self.window2.setGeometry(622, 100, 512, 384)
self.window1.show()
self.window2.show()
def closeEvent(self, event: QCloseEvent):
for win in (self.window1, self.window2):
win.can_close = True
win.close()
super(ControlWindow, self).closeEvent(event)
if __name__ == '__main__':
import sys
app = QApplication(sys.argv)
window = ControlWindow(win_name='ControlWindow (You can only close this one)')
window.show()
sys.exit(app.exec_())
The simplest way to do what you want to achieve is to keep track of the current focused widget, or, to be precise, the top level window of the last focused widget.
You can store the focused windows in the settings as a list, using a unique objectName for each window (you are already doing this, so you just need to use setObjectName()), then restore the window by showing them in the correct order as long as the object name matches.
class RememberWin(QMainWindow):
def __init__(self, win_name: str):
super(RememberWin, self).__init__()
self.win_name = win_name
self.setObjectName(win_name)
self.setWindowTitle(win_name)
self.can_close = False
# ...
class ControlWindow(RememberWin):
def __init__(self, win_name: str = "ControlWindow"):
# ...
self.settings = QSettings("PyQtExamples", "RememberWinTest")
self.zOrder = []
QApplication.instance().focusObjectChanged.connect(self.focusChanged)
windowOrder = self.settings.value('windowOrder', type='QStringList')
topLevelWindows = QApplication.topLevelWidgets()
if windowOrder:
for objName in windowOrder:
for win in topLevelWindows:
if win.objectName() == objName:
win.show()
else:
self.window1.show()
self.window2.show()
def focusChanged(self, obj):
if not obj or obj.window() == self.window():
return
if obj.window() in self.zOrder[:-1]:
self.zOrder.remove(obj.window())
self.zOrder.append(obj.window())
def closeEvent(self, event: QCloseEvent):
for win in (self.window1, self.window2):
win.can_close = True
win.close()
self.settings.setValue('windowOrder',
[w.window().objectName() for w in self.zOrder])
super(ControlWindow, self).closeEvent(event)

Force QTabBar tabs to stay as small as possible and ignore sizeHint

I'm trying to have a + button added to a QTabBar. There's a great solution from years ago, with a slight issue that it doesn't work with PySide2. The problem is caused by the tabs auto resizing to fill the sizeHint, which in this case isn't wanted as the extra space is needed. Is there a way I can disable this behaviour?
I've tried QTabBar.setExpanding(False), but according to this answer, the property is mostly ignored:
The bad news is that QTabWidget effectively ignores that property, because it always forces its tabs to be the minimum size (even if you set your own tab-bar).
The difference being in PySide2, it forces the tabs to be the preferred size, where I'd like the old behaviour of minimum size.
Edit: Example with minimal code. The sizeHint width stretches the tab across the full width, whereas in older Qt versions it doesn't do that. I can't really override tabSizeHint since I don't know what the original tab size should be.
import sys
from PySide2 import QtCore, QtWidgets
class TabBar(QtWidgets.QTabBar):
def sizeHint(self):
return QtCore.QSize(100000, super().sizeHint().height())
class Test(QtWidgets.QDialog):
def __init__(self, parent=None):
super(Test, self).__init__(parent)
layout = QtWidgets.QVBoxLayout()
self.setLayout(layout)
tabWidget = QtWidgets.QTabWidget()
tabWidget.setTabBar(TabBar())
layout.addWidget(tabWidget)
tabWidget.addTab(QtWidgets.QWidget(), 'this shouldnt be stretched')
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
test = Test()
test.show()
sys.exit(app.exec_())
I think there may be an easy solution to your problem (see below). Where the linked partial solution calculated absolute positioning for the '+' button, the real intent with Qt is always to let the layout engine do it's thing rather than trying to tell it specific sizes and positions. QTabWidget is basically a pre-built amalgamation of layouts and widgets, and sometimes you just have to skip the pre-built and build your own.
example of building a custom TabWidget with extra things across the TabBar:
import sys
from PySide2 import QtWidgets
from random import randint
class TabWidget(QtWidgets.QWidget):
def __init__(self):
super().__init__()
#layout for entire widget
vbox = QtWidgets.QVBoxLayout(self)
#top bar:
hbox = QtWidgets.QHBoxLayout()
vbox.addLayout(hbox)
self.tab_bar = QtWidgets.QTabBar()
self.tab_bar.setMovable(True)
hbox.addWidget(self.tab_bar)
spacer = QtWidgets.QSpacerItem(0,0,QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Fixed)
hbox.addSpacerItem(spacer)
add_tab = QtWidgets.QPushButton('+')
hbox.addWidget(add_tab)
#tab content area:
self.widget_stack = QtWidgets.QStackedLayout()
vbox.addLayout(self.widget_stack)
self.widgets = {}
#connect events
add_tab.clicked.connect(self.add_tab)
self.tab_bar.currentChanged.connect(self.currentChanged)
def add_tab(self):
tab_text = 'tab' + str(randint(0,100))
tab_index = self.tab_bar.addTab(tab_text)
widget = QtWidgets.QLabel(tab_text)
self.tab_bar.setTabData(tab_index, widget)
self.widget_stack.addWidget(widget)
self.tab_bar.setCurrentIndex(tab_index)
def currentChanged(self, i):
if i >= 0:
self.widget_stack.setCurrentWidget(self.tab_bar.tabData(i))
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
test = TabWidget()
test.show()
sys.exit(app.exec_())
All that said, I think the pre-built QTabWidget.setCornerWidget may be exactly what you're looking for (set a QPushButton to the upper-right widget). The example I wrote should much easier to customize, but also much more effort to re-implement all the same functionality. You will have to re-implement some of the signal logic to create / delete / select / rearrange tabs on your own. I only demonstrated simple implementation, which probably isn't bulletproof to all situations.
Using the code from Aaron as a base to start on, I managed to implement all the functionality required to work with my existing script:
from PySide2 import QtCore, QtWidgets
class TabBar(QtWidgets.QTabBar):
def minimumSizeHint(self):
"""Allow the tab bar to shrink as much as needed."""
minimumSizeHint = super(TabBar, self).minimumSizeHint()
return QtCore.QSize(0, minimumSizeHint.height())
class TabWidgetPlus(QtWidgets.QWidget):
tabOpenRequested = QtCore.Signal()
tabCountChanged = QtCore.Signal(int)
def __init__(self, parent=None):
self._addingTab = False
super(TabWidgetPlus, self).__init__(parent=parent)
# Main layout
layout = QtWidgets.QVBoxLayout(self)
layout.setContentsMargins(0, 0, 0, 0)
# Bar layout
self._tabBarLayout = QtWidgets.QHBoxLayout()
self._tabBarLayout.setContentsMargins(0, 0, 0, 0)
self._tabBarLayout.setSpacing(0)
layout.addLayout(self._tabBarLayout)
self._tabBar = TabBar()
self._tabBarLayout.addWidget(self._tabBar)
for method in (
'isMovable', 'setMovable',
'tabsClosable', 'setTabsClosable',
'tabIcon', 'setTabIcon',
'tabText', 'setTabText',
'currentIndex', 'setCurrentIndex',
'currentChanged', 'tabCloseRequested',
):
setattr(self, method, getattr(self._tabBar, method))
self._plusButton = QtWidgets.QPushButton('+')
self._tabBarLayout.addWidget(self._plusButton) # TODO: Find location to insert
self._plusButton.setFixedWidth(20)
self._tabBarLayout.addStretch()
# Content area
self._contentArea = QtWidgets.QStackedLayout()
layout.addLayout(self._contentArea)
# Signals
self.currentChanged.connect(self._currentChanged)
self._plusButton.clicked.connect(self.tabOpenRequested.emit)
# Final setup
self.installEventFilter(self)
#QtCore.Slot(int)
def _currentChanged(self, i):
"""Update the widget."""
if i >= 0 and not self._addingTab:
self._contentArea.setCurrentWidget(self.tabBar().tabData(i))
def eventFilter(self, obj, event):
"""Intercept events until the correct height is set."""
if event.type() == QtCore.QEvent.Show:
self.plusButton().setFixedHeight(self._tabBar.geometry().height())
self.removeEventFilter(self)
return False
def tabBarLayout(self):
return self._tabBarLayout
def tabBar(self):
return self._tabBar
def plusButton(self):
return self._plusButton
def tabAt(self, point):
"""Get the tab at a given point.
This takes any layout margins into account.
"""
offset = self.layout().contentsMargins().top() + self.tabBarLayout().contentsMargins().top()
return self.tabBar().tabAt(point - QtCore.QPoint(0, offset))
def addTab(self, widget, name=''):
"""Add a new tab.
Returns:
Tab index as an int.
"""
self._addingTab = True
tabBar = self.tabBar()
try:
index = tabBar.addTab(name)
tabBar.setTabData(index, widget)
self._contentArea.addWidget(widget)
finally:
self._addingTab = False
return index
def insertTab(self, index, widget, name=''):
"""Inserts a new tab.
If index is out of range, a new tab is appended.
Returns:
Tab index as an int.
"""
self._addingTab = True
tabBar = self.tabBar()
try:
index = tabBar.insertTab(index, name)
tabBar.setTabData(index, widget)
self._contentArea.insertWidget(index, widget)
finally:
self._addingTab = False
return index
def removeTab(self, index):
"""Remove a tab."""
tabBar = self.tabBar()
self._contentArea.removeWidget(tabBar.tabData(index))
tabBar.removeTab(index)
if __name__ == '__main__':
import sys
import random
app = QtWidgets.QApplication(sys.argv)
test = TabWidgetPlus()
test.addTab(QtWidgets.QPushButton(), 'yeah')
test.insertTab(0, QtWidgets.QCheckBox(), 'what')
test.insertTab(1, QtWidgets.QRadioButton(), 'no')
test.removeTab(1)
test.setMovable(True)
test.setTabsClosable(True)
def tabTest():
name = 'Tab ' + str(random.randint(0, 100))
index = test.addTab(QtWidgets.QLabel(name), name)
test.setCurrentIndex(index)
test.tabOpenRequested.connect(tabTest)
test.tabCloseRequested.connect(lambda index: test.removeTab(index))
test.show()
sys.exit(app.exec_())
The one difference is if you're using tabWidget.tabBar().tabAt(point), this is no longer guaranteed to be correct as it doesn't take any margins into account. I set the margins to 0 so this shouldn't be an issue, but I also included those corrections in TabWidgetPlus.tabAt.
I only copied a few methods from QTabBar to QTabWidget as some may need extra testing.

PyQt5 dynamic creation/destruction of widgets

I have an application where upon start up the user is presented with a dialog to chose number of 'objects' required. This then generates necessary objects in the main window using a for loop (i.e. object1, object2, etc.). I want to move this selection into the main window so that this can be changed without the need to restart the application. I have no idea how to approach this as I'm not sure how to dynamically create/destroy once the application is running. Here's an example code that generates tabs in a tab widget with some elements in each tab.
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
class SelectionWindow(QDialog):
def __init__(self):
QDialog.__init__(self)
self.settings = QSettings('Example', 'Example')
self.numberOfTabs = QSpinBox(value = self.settings.value('numberOfTabs', type=int, defaultValue = 3), minimum = 1)
self.layout = QFormLayout(self)
self.button = QPushButton(text = 'OK', clicked = self.buttonClicked)
self.layout.addRow('Select number of tabs', self.numberOfTabs)
self.layout.addRow(self.button)
def buttonClicked(self):
self.settings.setValue('numberOfTabs', self.numberOfTabs.value())
self.accept()
class MainWindow(QMainWindow):
def __init__(self):
QMainWindow.__init__(self)
self.settings = QSettings('Example', 'Example')
self.tabs = self.settings.value('numberOfTabs', type = int)
self.tabWidget = QTabWidget()
for i in range(1, self.tabs + 1):
exec(('self.tab{0} = QWidget()').format(i))
exec(("self.tabWidget.addTab(self.tab{0}, 'Tab{0}')").format(i))
exec(('self.lineEdit{0} = QLineEdit()').format(i))
exec(('self.spinBox{0} = QSpinBox()').format(i))
exec(('self.checkBox{0} = QCheckBox()').format(i))
exec(('self.layout{0} = QFormLayout(self.tab{0})').format(i))
exec(("self.layout{0}.addRow('Name', self.lineEdit{0})").format(i))
exec(("self.layout{0}.addRow('Value', self.spinBox{0})").format(i))
exec(("self.layout{0}.addRow('On/Off', self.checkBox{0})").format(i))
self.setCentralWidget(self.tabWidget)
if __name__ == "__main__":
import sys
app = QApplication(sys.argv)
dialog = SelectionWindow()
dialog.show()
if dialog.exec_() == SelectionWindow.Accepted:
mainwindow = MainWindow()
mainwindow.show()
sys.exit(app.exec_())
First of all, you should never use exec for things like these. Besides the security issues of using exec, it also makes your code less readable (and then much harder to debug) and hard to interact with.
A better (and more "elegant") solution is to use a common function to create tabs and, most importantly, setattr.
Also, you shouldn't use QSettings in this way, as it is mostly intended for cross-session persistent data, not to initialize an interface. For that case, you should just override the exec() method of the dialog and initialize the main window with that value as an argument.
And, even if it was the case (but I suggest you to avoid the above approach anyway), remember that to make settings persistent, at least organizationName and applicationName must be set.
class MainWindow(QMainWindow):
def __init__(self):
QMainWindow.__init__(self)
self.settings = QSettings('Example', 'Example')
# this value does not need to be a persistent instance attribute
tabCount = self.settings.value('numberOfTabs', type = int)
# create a main widget for the whole interface
central = QWidget()
mainLayout = QVBoxLayout(central)
tabCountSpin = QSpinBox(minimum=1)
mainLayout.addWidget(tabCountSpin)
tabCountSpin.setValue(tabCount)
tabCountSpin.valueChanged.connect(self.tabCountChanged)
self.tabWidget = QTabWidget()
mainLayout.addWidget(self.tabWidget)
for t in range(tabCount):
self.createTab(t)
self.setCentralWidget(central)
def createTab(self, t):
t += 1
tab = QWidget()
self.tabWidget.addTab(tab, 'Tab{}'.format(t))
layout = QFormLayout(tab)
# create all the widgets
lineEdit = QLineEdit()
spinBox = QSpinBox()
checkBox = QCheckBox()
# add them to the layout
layout.addRow('Name', lineEdit)
layout.addRow('Value', spinBox)
layout.addRow('On/Off', checkBox)
# keeping a "text" reference to the widget is useful, but not for
# everything, as tab can be accessed like this:
# tab = self.tabWidget.widget(index)
# and so its layout:
# tab.layout()
setattr(tab, 'lineEdit{}'.format(t), lineEdit)
setattr(tab, 'spinBox{}'.format(t), spinBox)
setattr(tab, 'checkBox{}'.format(t), checkBox)
def tabCountChanged(self, count):
if count == self.tabWidget.count():
return
elif count < self.tabWidget.count():
while self.tabWidget.count() > count:
# note that I'm not deleting the python reference to each object;
# you should use "del" for both the tab and its children
self.tabWidget.removeTab(count)
else:
for t in range(self.tabWidget.count(), count):
self.createTab(t)

QT, Python, QTreeView, custom widget, setData - lose reference after drag and drop

This question is similar to the one in this this topic Preserve QStandardItem subclasses in drag and drop but with issue that I cant find a good solution for. That topic partially helps but fail on more complex task.
When I create an item in QTreeView I put that item in my array but when I use drag&Drop the item gets deleted and I no longer have access to it. I know that its because drag and drop copies the item and not moves it so I should use setData. I cant setData to be an object because even then the object gets copied and I lose reference to it.
Here is an example
itemsArray = self.addNewRow
def addNewRow(self)
'''some code with more items'''
itemHolder = QStandardItem("ProgressBarItem")
widget = QProgressBar()
itemHolder.setData(widget)
inx = self.model.rowCount()
self.model.setItem(inx, 0, itemIcon)
self.model.setItem(inx, 1, itemName)
self.model.setItem(inx, 2, itemHolder)
ix = self.model.index(inx,2,QModelIndex())
self.treeView.setIndexWidget(ix, widget)
return [itemHolder, itemA, itemB, itemC]
#Simplified functionality
data = [xxx,xxx,xxx]
for items in itemsArray:
items[0].data().setPercentage(data[0])
items[1].data().setText(data[1])
items[2].data().setChecked(data[2])
The code above works if I won't move the widget. The second I drag/drop I lose reference I lose updates on all my items and I get crash.
RuntimeError: wrapped C/C++ object of type QProgressBar has been deleted
The way I can think of of fixing this problem is to loop over entire treeview recursively over each row/child and on name match update item.... Problem is that I will be refreshing treeview every 0.5 second and have 500+ rows with 5-15 items each. Meaning... I don't think that will be very fast/efficient... if I want to loop over 5 000 items every 0.5 second...
Can some one suggest how I could solve this problem? Perhaps I can edit dropEvent so it does not copy/paste item but rather move item.... This way I would not lose my object in array
Qt can only serialize objects that can be stored in a QVariant, so it's no surprise that this won't work with a QWidget. But even if it could serialize widgets, I still don't think it would work, because index-widgets belong to the view, not the model.
Anyway, I think you will have to keep references to the widgets separately, and only store a simple key in the model items. Then once the items are dropped, you can retrieve the widgets and reset them in the view.
Here's a working demo script:
from PyQt4 import QtCore, QtGui
class TreeView(QtGui.QTreeView):
def __init__(self, *args, **kwargs):
super(TreeView, self).__init__(*args, **kwargs)
self.setDragDropMode(QtGui.QAbstractItemView.InternalMove)
self.setSelectionMode(QtGui.QAbstractItemView.ExtendedSelection)
self.setAllColumnsShowFocus(True)
self.setModel(QtGui.QStandardItemModel(self))
self._widgets = {}
self._dropping = False
self._droprange = range(0)
def dropEvent(self, event):
self._dropping = True
super(TreeView, self).dropEvent(event)
for row in self._droprange:
item = self.model().item(row, 2)
self.setIndexWidget(item.index(), self._widgets[item.data()])
self._droprange = range(0)
self._dropping = False
def rowsInserted(self, parent, start, end):
super(TreeView, self).rowsInserted(parent, start, end)
if self._dropping:
self._droprange = range(start, end + 1)
def addNewRow(self, name):
model = self.model()
itemIcon = QtGui.QStandardItem()
pixmap = QtGui.QPixmap(16, 16)
pixmap.fill(QtGui.QColor(name))
itemIcon.setIcon(QtGui.QIcon(pixmap))
itemName = QtGui.QStandardItem(name.title())
itemHolder = QtGui.QStandardItem('ProgressBarItem')
widget = QtGui.QProgressBar()
widget.setValue(5 * (model.rowCount() + 1))
key = id(widget)
self._widgets[key] = widget
itemHolder.setData(key)
model.appendRow([itemIcon, itemName, itemHolder])
self.setIndexWidget(model.indexFromItem(itemHolder), widget)
class Window(QtGui.QWidget):
def __init__(self):
super(Window, self).__init__()
self.treeView = TreeView()
for name in 'red yellow green purple blue orange'.split():
self.treeView.addNewRow(name)
layout = QtGui.QVBoxLayout(self)
layout.addWidget(self.treeView)
if __name__ == '__main__':
import sys
app = QtGui.QApplication(sys.argv)
window = Window()
window.setGeometry(500, 150, 600, 400)
window.show()
sys.exit(app.exec_())

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