Develop Reference

PyQt need to throw custom widgets into a list and be able to move them around

I have been fighting with custom widgets and lists for weeks now.
I have the ability to add a custom widget to a QListWidget. My issue is the insertItem seems to be buggy as it always drops it to the bottom of the list no matter what row I tell it to go to.
def AddToInitiative(self):
creature = self.comboBoxSelectCharacter.currentText()
if(creature):
widget = self.NewItemWidget()
customWidgetItem = QtGui.QListWidgetItem(self.initiativeList)
customWidgetItem.setSizeHint(QtCore.QSize(400,50))
self.initiativeList.addItem(customWidgetItem)
self.initiativeList.setItemWidget(customWidgetItem, widget)
widget.lineName.setText(creature)
return
def NewItemWidget(self):
customWidget = creature_initiative_object.InitCreatureObject()
customWidget.btnRemove.clicked.connect(self.ItemButtonClicked)
customWidget.btnInfo.clicked.connect(self.ItemButtonClicked)
customWidget.btnIncreaseInitOrder.clicked.connect(self.ItemButtonClicked)
customWidget.btnDecreaseInitOrder.clicked.connect(self.ItemButtonClicked)
return customWidget
def ChangeInit(self, row, direction, oldwidget):
item = self.initiativeList.takeItem(row)
widget = self.NewItemWidget()
widget.lineName.setText(oldwidget.lineName.text())
customWidgetItem = QtGui.QListWidgetItem(self.initiativeList)
customWidgetItem.setSizeHint(QtCore.QSize(400,50))
self.initiativeList.insertItem((row + direction), customWidgetItem)
self.initiativeList.setItemWidget(customWidgetItem, widget)
self.initiativeList.setCurrentRow(row+direction)
If I try to move the item up or down the list it always just goes straight to the bottom despite assigning the row number. I've output the row number and count to verify it should be saying the right row.
Do you know a way to do this with QListWidget for custom widgets that need to preserve data? Is there a better module to use?
I've looked at QListView, QBoxLayout, and a few others without being able to get it to work as well as QListWidget.

Adding/Removing QSlider widgets on PyQt5

I want to dynamically change the number of sliders on my application window, in dependence of the number of checked items in a QStandardItemModel structure.
My application window has an instance of QVBoxLayout called sliders, which I update when a button is pressed:
first removing all sliders eventually in there:
self.sliders.removeWidget(slider)
And then creating a new set.
The relevant code:
def create_sliders(self):
if len(self.sliders_list):
for sl in self.sliders_list:
self.sliders.removeWidget(sl)
self.sliders_list = []
for index in range(self.model.rowCount()):
if self.model.item(index).checkState():
slid = QSlider(Qt.Horizontal)
self.sliders.addWidget(slid)
self.sliders_list.append(slid)
The principle seems to work, however what happens is weird as the deleted sliders do not really disappear but it is as they were 'disconnected' from the underlying layout.
When created, the sliders keep their position among other elements while I resize the main window.
However, once they've been removed, they occupy a fixed position and can for instance disappear if I reduce the size of the window.
Unfortunately I'm having difficulties in linking images (it says the format is not supported when I try to link from pasteboard), so I hope this description is enough to highlight the issue.
Do I have to remove the sliders using a different procedure?
EDIT
Thanks to #eyllansec for his reply, it condenses a bunch of other replies around the topic, which I wasn't able to find as I did not know the method deleteLater() which is the key to get rid of widgets inside a QLayout.
I am marking it as my chosen (hey, it's the only one and it works, after all!), however I want to propose my own code which also works with minimal changes w.r.t. to what I proposed in the beginning.
The key point here is that I was using the metod QLayout.removeWidget(QWidget) which I was wrongly thinking, it would..er..Remove the widget! But actually what it does is (if I understood it right) remove it from the layout instance.
That is why it was still hanging in my window, although it seemed disconnected
Manual reference
Also, the proposed code is far more general than what I need, as it is a recursion over layout contents, which could in principle be both other QLayout objects or QWidgets (or even Qspacer), and be organized in a hierarchy (i.e., a QWidget QLayout within a QLayout and so on).
check this other answer
From there, the use of recursion and the series of if-then constructs.
My case is much simpler though, as I use this QVLayout instance to just place my QSliders and this will be all. So, for me, I stick to my list for now as I do not like the formalism of QLayout.TakeAt(n) and I don't need it. I was glad that the references I build in a list are absolutely fine to work with.
In the end, this is the slightly changed code that works for me in this case:
def create_sliders(self):
if len(self.sliders_list):
for sl in self.sliders_list:
sl.deleteLater()
self.sliders_list = []
for index in range(self.model.rowCount()):
if self.model.item(index).checkState():
slid = QSlider(Qt.Horizontal)
self.sliders.addWidget(slid)
self.sliders_list.append(slid)

It is not necessary to save the sliders in a list, they can be accessed through the layout where it is contained. I have implemented a function that deletes the elements within a layout. The solution is as follows:
def create_sliders(self):
self.clearLayout(self.sliders)
for index in range(self.model.rowCount()):
if self.model.item(index).checkState():
slid = QSlider(Qt.Horizontal)
self.sliders.addWidget(slid)
def clearLayout(self, layout):
if layout:
while layout.count():
item = layout.takeAt(0)
widget = item.widget()
if widget:
widget.deleteLater()
else :
self.clearLayout(item.layout())
layout.removeItem(item)

Multiple ListBox columns in urwid

I am trying to build an interface as part of a console application that reads an output file and displays part of its contents in a window (split vertically) as a scrollable list. The user should be able to choose items from this list, which when selected show up in the adjacent window. Switching to this adjacent window and selecting items should then remove them. When the user hits 'Q' or some other appropriate keypress, the interface should exit and the choices are then available to the main program for further processing.
I am trying to build this using urwid. I can get the results to show up in a ListBox widget, but when I try to wrap this and a separate instance of a ListBox widget in a Columns widget, the program throws an error on calling the mainloop. Basically, something like this:
listbox1 = urwid.ListBox(urwid.SimpleListWalker[<lines>])
listbox2 = urwid.ListBox(urwid.SimpleListWalker[])
urwid.MainLoop(urwid.Columns([listbox1, listbox2])).run()
I then get:
AttributeError: 'listbox1' object has no attribute 'rows'
I guess because it is a 'flow' style widget it has no specified number of rows, and since the Columns object would be the top level widget, calls to render fail due to not being able to determine the overall size of the screen? If so, what is the best way to work around this?
EDIT: Can simply wrap the columns object in Frame without calling header or footer and get desired output.

Python Tkinter - Multiple entry box with same validation

I have created around 5 Entry boxes and binded them as well. Take this as model:
def makeEntry(self, master, data):
self.entry = Entry(master, width=8, textvariable=data)
self.entry.bind("<Leave>", lambda event, value=data: self.validate(event, value))
Now, I did also a validate method that check if the input was a string (and if so, the highlight background of the entry would change to red). The problem which is still taking me a lot of time is that I would need that the method should be able to check every entries, and if at least one of them has got a red background, then a final button should be disabled (button.configure(state=DISABLED)).
With just one entry it would be much easier, I would simply check if the background was red (status = str(self.myOneEntry.cget("highlightbackground"))), but what about with more entries?

If you want to check all of your entries, keep them in a list. Then, write a function that iterates over the list and sets the button state to disabled if any widget has a red background. You can then call this whenever something changes, such as within your validation function for each widget.
Example:
class Example(...):
def __init__(...):
self.entries = []
for data in ("one","two","three"):
entry = makeEntry(...)
self.entries.append(entry)
def _update_button(self):
for entry in self.entries:
if entry.cget("background") == "red":
self.button.configure(state="disabled")
return
self.button.configure(state="normal")
Note: you'll need to make sure that makeEntry(...) returns a reference to the created widget.
Also, you don't have to use makeEntry. You can create your widgets however you want. The point is to save references to the widgets in a data structure that you can iterate over. It doesn't matter how the widgets are created.

PyQt - How to connect multiple signals to the same widget

[ ]All1 [ ]All2
[ ]checkbox1A [ ]checkbox1B
[ ]checkbox2A [ ]checkbox2B
Based on the chart above, a few things need to happen:
The All checkboxes only affect the on/off of the column it resides in, and checks on/off all the checkboxes in that column.
All checkboxes work in pairs, so if checkbox1A is on/off, checkbox1B needs to be on/off
If an All checkbox is checked on, and then the user proceeds to check off one or more checkbox in the column, the All checkbox should be unchecked, but all the checkboxes that are already checked should remain checked.
So really this is more like a chain reaction setup. If checkbox All1 is on, then chieckbox1A and 2A will be on, and because they are on, checkbox1B and 2B are also on, but checkbox All2 remains off. I tried hooking up the signals based on this logic, but only the paired logic works 100%. The All checkbox logic only works 50% of the time, and not accurately, and there's no way for me to turn off the All checkbox without turning all already checked checkboxes off.
Really really need help ... T-T
Sample code:
cbPairKeys = cbPairs.keys()
for key in cbPairKeys:
cbOne = cbPairs[key][0][0]
cbTwo = cbPairs[key][1][0]
cbOne.stateChanged.connect(self.syncCB)
cbTwo.stateChanged.connect(self.syncCB)
def syncCB(self):
pairKeys = cbPairs.keys()
for keys in pairKeys:
cbOne = cbPairs[keys][0][0]
cbOneAllCB = cbPairs[keys][0][4]
cbTwo = cbPairs[keys][1][0]
cbTwoAllCB = cbPairs[keys][1][4]
if self.sender() == cbOne:
if cbOne.isChecked() or cbTwoAllCB.isChecked():
cbTwo.setChecked(True)
else:
cbTwo.setChecked(False)
else:
if cbTwo.isChecked() or cbOneAllCB.isChecked():
cbOne.setChecked(True)
else:
cbOne.setChecked(False)
EDIT
Thanks to user Avaris's help and patience, I was able to reduce the code down to something much cleaner and works 100% of the time on the 1st and 2nd desired behavior:
#Connect checkbox pairs
cbPairKeys = cbPairs.keys()
for key in cbPairKeys:
cbOne = cbPairs[key][0][0]
cbTwo = cbPairs[key][1][0]
cbOne.toggled.connect(cbTwo.setChecked)
cbTwo.toggled.connect(cbOne.setChecked)
#Connect allCB and allRO signals
cbsKeys = allCBList.keys()
for keys in cbsKeys:
for checkbox in allCBList[keys]:
keys.toggled.connect(checkbox.setChecked)
Only need help on turning off the All checkbox when the user selectively turns off the modular checkboxes now

If I'm understanding your data structure, I have a solution. Correct me if I'm wrong: allCBList is a dict (confusing name! :) ). Its keys are the all* checkboxes. And a value allCBList[key] is a list with checkboxes associated with that all checkbox. For your example structure it'll be something like this:
{ All1 : [checkbox1A, checkbox1B],
All2 : [checkbox2A, checkbox2B]}
Then what you need to is this: when a checkbox is toggled and it is in checked state, then you need to check the All* checkbox if all the other checkboxes are in checked state. Otherwise it will be unchecked.
for key, checkboxes in allCBList.iteritems():
for checkbox in checkboxes:
checkbox.toggled.connect(lambda checked, checkboxes=checkboxes, key=key: key.setChecked(checked and all(checkbox.isChecked() for checkbox in checkboxes))
I guess, this statement requires a bit of explanation:
lambda checked, checkboxes=checkboxes, key=key:
lambda creates the callable that is connected to the signal. toggled passes checkbox status, and it will be passed to checked variable. checkboxes=checkboxes and key=key parts pass the current values to checkboxes and key parameters of the lambda. (You need this because of the closure in lambdas)
Next comes:
key.setChecked(...)
We are setting the checked state of key which is the appropriate All* checkbox. And inside this:
checked and all(checkbox.isChecked() for checkbox in checkboxes)
all is True if everything inside is True, where we check every checkboxs state. And this will return True if all are checked (i.e. isChecked() returns True).
checked and ... part is there to short-circuit the all. If the current checkbox turns unchecked, then we don't need to check others. All* would be unchecked.
(PS: By the way, you don't need to get .keys() of a dict to iterate over keys. You can just iterate over the dict and it will iterate over its keys.)
Edit: Just to avoid chain reaction with All* checkboxes toggled by clicking any sub-checkboxes, it's necessary to change the signal for All* checkboxes to clicked, instead of toggled. So, the All* check boxes will affect other below them only in the case of user interaction.
In the end, your modified code will be:
# Connect checkbox pairs
# you just use the values
# change 'itervalues' to 'values' if you are on Python 3.x
for cbPair in cbPairs.itervalues():
cbOne = cbPair[0][0]
cbTwo = cbPair[1][0]
cbOne.toggled.connect(cbTwo.setChecked)
cbTwo.toggled.connect(cbOne.setChecked)
# Connect allCB and allRO signals
# change 'iteritems' to 'items' if you are on Python 3.x
for key, checkboxes in allCBList.iteritems():
for checkbox in checkboxes:
key.clicked.connect(checkbox.setChecked)
checkbox.toggled.connect(lambda checked, checkboxes=checkboxes, key=key: key.setChecked(checked and all(checkbox.isChecked() for checkbox in checkboxes))

Your problem is that your checkboxes are connecting the toggled signal and toggling their state in your connected slots so the signal is emitted again (so the slots are executed again...) and you get unpredictable results. Obviously that is not your wanted behavior. You can fix it in several ways:
by disconnecting the signals at the beginning of the slots and connecting them again at the end
by using some clever code that controls the re-emission of signals (I think this is what Avari's code does in a very compact way, but I'm not completely sure)
by using a clicked signal because it is not re-emitted when the checkbox state changes
Which approach you follow is up to you. The following code uses the third approach:
self.cbPair = {}
self.cbPair['0'] = (QtGui.QCheckBox('all1', parent),
QtGui.QCheckBox('all2', parent))
self.cbPair['1'] = (QtGui.QCheckBox('1a', parent),
QtGui.QCheckBox('1b', parent))
self.cbPair['2'] = (QtGui.QCheckBox('2a', parent),
QtGui.QCheckBox('2b', parent))
for v in self.cbPair.values():
for cb in v:
cb.clicked.connect(self.updateCB)
def updateCB(self):
cb = self.sender()
is_checked = cb.isChecked()
id = str(cb.text())
try:
# Update a whole column
column = int(id[-1]) - 1
rows = ('1', '2')
except ValueError:
# Update a row and the headers row
rows = (id[0], )
column = {'a': 1, 'b': 0}.get(id[-1])
if not is_checked:
for c in (0, 1):
self.cbPair['0'][c].setChecked(is_checked)
for r in rows:
self.cbPair[r][column].setChecked(is_checked)
Note that I'm using the checkboxes text as a UID from wich row and colum values are calculated. If you want to use different text labels for your checkboxes you may need to set the UIDs as attributes to every checkbox.