Develop Reference

How to save selected element from combobox as variable in PyQt5?

I'm interested in how to save a selected value from my combobox as variable, so when I press e.g. B then I want it to be saved as SelectedValueCBox = selected value, which would be B in this case.
Thank you for your help
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
import sys
class App(QMainWindow):
def __init__(self):
super().__init__()
self.title = "PyQt5 - StockWindow"
self.left = 0
self.top = 0
self.width = 200
self.height = 300
self.setWindowTitle(self.title)
self.setGeometry(self.left, self.top, self.width, self.height)
self.tab_widget = MyTabWidget(self)
self.setCentralWidget(self.tab_widget)
self.show()
class MyTabWidget(QWidget):
def __init__(self, parent):
super(QWidget, self).__init__(parent)
self.layout = QVBoxLayout(self)
#self.layout = QGridLayout(self)
self.tabs = QTabWidget()
self.tab1 = QWidget()
self.tabs.resize(300, 200)
self.tabs.addTab(self.tab1, "Stock-Picker")
self.tab1.layout = QGridLayout(self)
button = QToolButton()
self.tab1.layout.addWidget(button, 1,1,1,1)
d = {'AEX':['A','B','C'], 'ATX':['D','E','F'], 'BEL20':['G','H','I'], 'BIST100':['J','K','L']}
def callback_factory(k, v):
return lambda: button.setText('{0}_{1}'.format(k, v))
menu = QMenu()
self.tab1.layout.addWidget(menu, 1,1,1,1)
for k, vals in d.items():
sub_menu = menu.addMenu(k)
for v in vals:
action = sub_menu.addAction(str(v))
action.triggered.connect(callback_factory(k, v))
button.setMenu(menu)
self.tab1.setLayout(self.tab1.layout)
self.layout.addWidget(self.tabs)
self.setLayout(self.layout)
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = App()
sys.exit(app.exec_())

Since you're already returning a lambda for the connection, the solution is to use a function instead.
class MyTabWidget(QWidget):
def __init__(self, parent):
# ...
def callback_factory(k, v):
def func():
self.selectedValueCBox = v
button.setText('{0}_{1}'.format(k, v))
return func
# ...
self.selectedValueCBox = None
Note that your code also has many issues.
First of all, you should not add the menu to the layout: not only it doesn't make any sense (the menu should pop up, while adding it to a layout makes it "embed" into the widget, and that's not good), but it also creates graphical issues especially because you added the menu to the same grid "slot" (1, 1, 1, 1) which is already occupied by the button.
Creating a layout with a widget as argument automatically sets the layout to that widget. While in your case it doesn't create a big issue (since you've already set the layout) you should not create self.tab1.layout with self. Also, since you've already set the QVBoxLayout (due to the parent argument), there's no need to call setLayout() again.
A widget container makes sense if you're actually going to add more than one widget. You're only adding a QTabWidget to its layout, so it's almost useless, and you should just subclass from QTabWidget instead.
Calling resize on a widget that is going to be added on a layout is useless, as the layout will take care of the resizing and the previous resize call will be completely ignored. resize() makes only sense for top level widgets (windows) or the rare case of widgets not managed by a layout.
self.layout() is an existing property of all QWidgets, you should not overwrite it. The same with self.width() and self.height() you used in the App class.
App should refer to an application class, but you're using it for a QMainWindow. They are radically different types of classes.
Finally, you have no combobox in your code. A combobox is widget that is completely different from a drop down menu like the one you're using. I suggest you to be more careful with the terminology in the future, otherwise your question would result very confusing, preventing people to actually being able to help you.

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_())

PyQt How to remove a layout from a layout

datainputHbox = QHBoxLayout()
layout = QVBoxLayout(self)
layout.addLayout(datainputHbox)
pagedatainputdeletboxbutton1.clicked.connect(lambda:self.boxdelete(datainputHbox))
def boxdelete(self, box):
This is the PyQt proragm
How write boxdelete funtion in order to remove datainputHbox form layout. I try a lot of. However I just can remove all the widgets but cannot remove layout.

As a generic answer: taken from here with slight, but important changes: you should not call widget.deleteLater(). At least in my case this caused python to crash
Global Function
def deleteItemsOfLayout(layout):
if layout is not None:
while layout.count():
item = layout.takeAt(0)
widget = item.widget()
if widget is not None:
widget.setParent(None)
else:
deleteItemsOfLayout(item.layout())
together with the boxdelete function from Brendan Abel's answer
def boxdelete(self, box):
for i in range(self.vlayout.count()):
layout_item = self.vlayout.itemAt(i)
if layout_item.layout() == box:
deleteItemsOfLayout(layout_item.layout())
self.vlayout.removeItem(layout_item)
break

You can remove QLayouts by getting their corresponding QLayoutItem and removing it. You should also be storing references to your Layouts, otherwise there is no other way to access them later on unless you know the widget they belong to.
datainputHbox = QHBoxLayout()
self.vlayout = QVBoxLayout(self)
layout.addLayout(datainputHbox)
pagedatainputdeletboxbutton1.clicked.connect(lambda: self.boxdelete(datainputHbox))
def boxdelete(self, box):
for i in range(self.vlayout.count()):
layout_item = self.vlayout.itemAt(i)
if layout_item.layout() == box:
self.vlayout.removeItem(layout_item)
return

A single function that implements TheTrowser's answer, arguably cleaner:
def clear_item(self, item):
if hasattr(item, "layout"):
if callable(item.layout):
layout = item.layout()
else:
layout = None
if hasattr(item, "widget"):
if callable(item.widget):
widget = item.widget()
else:
widget = None
if widget:
widget.setParent(None)
elif layout:
for i in reversed(range(layout.count())):
self.clear_item(layout.itemAt(i))

How can I get right-click context menus for clicks in QTableView header?

The sample code below (heavily influenced from here) has a right-click context menu that will appear as the user clicks the cells in the table. Is it possible to have a different right-click context menu for right-clicks in the header of the table? If so, how can I change the code to incorporate this?
import re
import operator
import os
import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *
def main():
app = QApplication(sys.argv)
w = MyWindow()
w.show()
sys.exit(app.exec_())
class MyWindow(QWidget):
def __init__(self, *args):
QWidget.__init__(self, *args)
self.tabledata = [('apple', 'red', 'small'),
('apple', 'red', 'medium'),
('apple', 'green', 'small'),
('banana', 'yellow', 'large')]
self.header = ['fruit', 'color', 'size']
# create table
self.createTable()
# layout
layout = QVBoxLayout()
layout.addWidget(self.tv)
self.setLayout(layout)
def popup(self, pos):
for i in self.tv.selectionModel().selection().indexes():
print i.row(), i.column()
menu = QMenu()
quitAction = menu.addAction("Quit")
action = menu.exec_(self.mapToGlobal(pos))
if action == quitAction:
qApp.quit()
def createTable(self):
# create the view
self.tv = QTableView()
self.tv.setStyleSheet("gridline-color: rgb(191, 191, 191)")
self.tv.setContextMenuPolicy(Qt.CustomContextMenu)
self.tv.customContextMenuRequested.connect(self.popup)
# set the table model
tm = MyTableModel(self.tabledata, self.header, self)
self.tv.setModel(tm)
# set the minimum size
self.tv.setMinimumSize(400, 300)
# hide grid
self.tv.setShowGrid(True)
# set the font
font = QFont("Calibri (Body)", 12)
self.tv.setFont(font)
# hide vertical header
vh = self.tv.verticalHeader()
vh.setVisible(False)
# set horizontal header properties
hh = self.tv.horizontalHeader()
hh.setStretchLastSection(True)
# set column width to fit contents
self.tv.resizeColumnsToContents()
# set row height
nrows = len(self.tabledata)
for row in xrange(nrows):
self.tv.setRowHeight(row, 18)
# enable sorting
self.tv.setSortingEnabled(True)
return self.tv
class MyTableModel(QAbstractTableModel):
def __init__(self, datain, headerdata, parent=None, *args):
""" datain: a list of lists
headerdata: a list of strings
"""
QAbstractTableModel.__init__(self, parent, *args)
self.arraydata = datain
self.headerdata = headerdata
def rowCount(self, parent):
return len(self.arraydata)
def columnCount(self, parent):
return len(self.arraydata[0])
def data(self, index, role):
if not index.isValid():
return QVariant()
elif role != Qt.DisplayRole:
return QVariant()
return QVariant(self.arraydata[index.row()][index.column()])
def headerData(self, col, orientation, role):
if orientation == Qt.Horizontal and role == Qt.DisplayRole:
return QVariant(self.headerdata[col])
return QVariant()
def sort(self, Ncol, order):
"""Sort table by given column number.
"""
self.emit(SIGNAL("layoutAboutToBeChanged()"))
self.arraydata = sorted(self.arraydata, key=operator.itemgetter(Ncol))
if order == Qt.DescendingOrder:
self.arraydata.reverse()
self.emit(SIGNAL("layoutChanged()"))
if __name__ == "__main__":
main()

Turned out to be simpler than I thought. In the same manner as I add the popup menu for the QTableView widget itself, I can just get the header from table object and then attach a context menu in the same way as I did with the regular context menu.
headers = self.tv.horizontalHeader()
headers.setContextMenuPolicy(Qt.CustomContextMenu)
headers.customContextMenuRequested.connect(self.header_popup)

There's another potentially more powerful way to do this if you take the step and inherit the view instead of simply composing it. Does custom context menu work here? Yes, but why does anything other than the view need to know about it? It also will help better shape your code to deal with other issues properly. Currently the implementation doesn't provide any encapsulation, cohesion or support separation of responsibility. In the end you will have one big blob which is the antithesis of good design.
I mention this because you seem to be placing all of the GUI Logic in this ever growing main function, and its the reason you ended up putting the sort implementation inside your model, which makes no sense to me. (What if you have two views of the model, you are forcing them to be sorted in the same way)
Is it more code? Yes, but it gives you more power which I think is worth mentioning. Below I'm demonstrating how to handle the headers and also any given cell you want. Also note that in my implementation if some OTHER widget exists which also defines a context menu event handler it will potentially get a chance to have crack at handling the event after mine; so that if someone else adds a handler for only certain cases they can do so without complicating my code. Part of doing this is marking if you handled the event or not.
Enough of my rambling and thoughts here's the code:
#Alteration : instead of self.tv = QTableView...
self.tv = MyTableView()
....
# somewhere in your TableView object's __init__ method
# yeah IMHO you should be inheriting and thus extending TableView
class MyTableView(QTableView):
def __init__(self, parent = None):
super(MyTableView, self).__init__()
self.setContextMenuPolicy(Qt.DefaultContextMenu)
## uniform one for the horizontal headers.
self.horizontalHeader().setContextMenuPolicy(Qt.ActionsContextMenu)
''' Build a header action list once instead of every time they click it'''
doSomething = QAction("&DoSomething", self.verticalHeader(),
statusTip = "Do something uniformly for headerss",
triggered = SOME_FUNCTION
self.verticalHeader().addAction(doSomething)
...
return
def contextMenuEvent(self, event)
''' The super function that can handle each cell as you want it'''
handled = False
index = self.indexAt(event.pos())
menu = QMenu()
#an action for everyone
every = QAction("I'm for everyone", menu, triggered = FOO)
if index.column() == N: #treat the Nth column special row...
action_1 = QAction("Something Awesome", menu,
triggered = SOME_FUNCTION_TO_CALL )
action_2 = QAction("Something Else Awesome", menu,
triggered = SOME_OTHER_FUNCTION )
menu.addActions([action_1, action_2])
handled = True
pass
elif index.column() == SOME_OTHER_SPECIAL_COLUMN:
action_1 = QAction("Uh Oh", menu, triggered = YET_ANOTHER_FUNCTION)
menu.addActions([action_1])
handled = True
pass
if handled:
menu.addAction(every)
menu.exec_(event.globalPos())
event.accept() #TELL QT IVE HANDLED THIS THING
pass
else:
event.ignore() #GIVE SOMEONE ELSE A CHANCE TO HANDLE IT
pass
return
pass #end of class