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Pyqt5: How to use SH_ToolTip_WakeUpDelay?

I've read that I can use QStyle.SH_ToolTip_WakeUpDelay to create a delay before the tool tip is shown, but I didn't figured out how exactly. I already read this question: How do I use QStyle::SH_ToolTip_WakeUpDelay to set tooltip wake-up time?
I'm not familiar with C++, but I tried to recreate it. I just made a class and overwrited the method styleHint, but it doesn't work.
My code:
class ProxyStyle(QProxyStyle):
def __init__(self):
super().__init__()
def styleHint(self, hint: QStyle.StyleHint, option: Optional['QStyleOption'] = ..., widget: Optional[QWidget] = ..., returnData: Optional['QStyleHintReturn'] = ...) -> int:
if hint == QStyle.SH_ToolTip_WakeUpDelay:
return 1000 # I just assumed it's in milliseconds, so I did 1000 to have a delay of 1s.
return QProxyStyle.styleHint(hint, option, widget, returnData)
As the guy answered in the above mentioned question, I added an instance of the class to my application. I don't know exactly if I understood it correctly, but I just did that:
proxyStyle = QProxyStyle()
app = QApplication([proxyStyle])
app.exec()
Edit
I did it like that now, but it also doesn't work (I expect a 1s delay):
proxyStyle = QProxyStyle()
app = QApplication([])
app.setStyle(proxyStyle)

Selecting the top-most item of a QTreeView

I have a Treeview (inherits from QTreeView) with model QFileSystemModel. This Treeview object is added to another widget with a QPushButton. The button will open a directory through a QFileDialog, and call the Treeview's set_directory method. The method will set the root path of the model to the selected directory and will modify the root index of the tree view. The top-most item in the treeview is then selected.
However, when selecting a directory for the first time, the top-most item is not selected. Commenting out line 11: self.model.directoryLoaded.connect(self.set_directory), solves the issue. But this means the set_directory method is called twice:
# default directory opened
<class 'NoneType'>
# open new directory, set_directory called twice
<class 'NoneType'>
<class 'PyQt5.QtWidgets.QFileSystemModel'>
As seen on the command line output, the QModelIndex.model() method returns a NoneType when selecting a directory for the first time. How do I set the treeview's current index to the top most item without calling the set_directory method twice? And why is the QModelIndex model a NoneType when the directory has not been visited?
Main script below:
from PyQt5.QtWidgets import QPushButton, QTreeView, QFileSystemModel, QWidget, QFileDialog, QApplication, QHBoxLayout
import sys
class Treeview(QTreeView):
def __init__(self, parent=None):
super(QTreeView, self).__init__(parent)
self.model = QFileSystemModel()
self.setModel(self.model)
self.set_directory(".")
# self.model.directoryLoaded.connect(self.set_directory)
def set_directory(self, path):
self.setRootIndex(self.model.setRootPath(path))
self.setCurrentIndex(self.model.index(0, 0, self.rootIndex()))
print(type(self.model.index(0, 0, self.rootIndex()).model()))
class MainWidget(QWidget):
def __init__(self, parent=None):
super(QWidget, self).__init__(parent)
self.tview = Treeview(self)
vlayout = QHBoxLayout(self)
vlayout.addWidget(self.tview)
open_button = QPushButton(self)
open_button.clicked.connect(self.open_dir)
vlayout.addWidget(open_button)
def open_dir(self):
filepath = QFileDialog.getExistingDirectory(self)
if filepath:
self.tview.set_directory(filepath)
if __name__ == '__main__':
app = QApplication(sys.argv)
widget = MainWidget()
widget.show()
sys.exit(app.exec_())

There are three problems:
directoryLoaded is called whenever the contents of a directory are loaded the first time, which happens asynchronously on a separate thread; if the contents of the "root" directory has never been loaded yet, it will have no children yet, so any attempt to access the children of the root index will return invalid indexes (that's why you get None);
the signal is also sent whenever a directory is expanded in the tree for the first time, which creates a problem if you connect it to set_directory: if you open the folder "home" and then expand the directory "documents", the model will load all its contents and emit the directoryLoaded for the "documents" folder, which will then call set_directory in turn once again;
the file system model also sorts items (alphabetically by default, with directories first), and this means that it will need some more time to get what you believe is the first item: for performance reasons, the OS returns the contents of a directory depending on the file system, which depends on its implementation: sometimes it's sorted by creation/modification time, others by the physical position/index of the blocks, etc;
Considering the above, you cannot rely on directoryLoaded (and surely you should not connect it to set_directory), but you can use the layoutChanged signal, since it's always emitted whenever sorting has completed (and QFileSystemModel always sorts the model when the root changes); the only catch is that you must do it only when needed.
The solution is to create a function that tries to set the top item, if it's not valid then it will connect itself to the layoutChanged signal; at that point, the signal will be emitted when the model has completed its job, and the top index has become available. Using a flag helps us to know if the signal has been connected, and then disconnect it, which is important in case you need to support sorting.
class Treeview(QTreeView):
layoutCheck = False
def __init__(self, parent=None):
super(QTreeView, self).__init__(parent)
self.model = QFileSystemModel()
self.setModel(self.model)
self.set_directory(QDir.currentPath())
self.setSortingEnabled(True)
def setTopIndex(self):
topIndex = self.model.index(0, 0, self.rootIndex())
print(topIndex.isValid(), topIndex.model())
if topIndex.isValid():
self.setCurrentIndex(topIndex)
if self.layoutCheck:
self.model.layoutChanged.disconnect(self.setTopIndex)
self.layoutCheck = False
else:
if not self.layoutCheck:
self.model.layoutChanged.connect(self.setTopIndex)
self.layoutCheck = True
def set_directory(self, path):
self.setRootIndex(self.model.setRootPath(path))
self.setTopIndex()
Please consider that the layoutCheck flag is very important, for many reasons:
as explained before, layoutChanged is always emitted when the model is sorted; this not only happens when trying to sort using the headers, but also when files or directories are being added;
signal connections are not exclusive, and you can even connect the same signal to the same slot/function more than once, with the result that the function will be called as many time as it's been connected; if you're not very careful, you could risk recursion;
the flag works fine also for empty directories, avoiding the above risk of recursion; if a new root directory is opened and it's empty, it will obviously return an invalid index for the top item (since there's none), but the signal will be disconnected in any case: if another directory (with contents) is opened but not yet loaded, the signal won't be connected again, and if, instead, the contents have been already loaded, it will disconnect it no matter what;
A possibility is to use the Qt.UniqueConnection connection type and a try block for the disconnection, but, while this approach works and is consistent, it's a bit cumbersome: as long as the connection is always paired with the setting, using a basic boolean flag is much simpler and easier to read and understand.

Getting parent of wrapInstance causes window to break

I've been using a modified version of this code to wrap a Qt window inside Maya's own workspaceControl. To get the outside level of the widget to query geometry, size, move, etc, I actually need to do self.parent().parent().parent().parent().parent(), since it's wrapped within quite a lot of widgets.
I've been working around one or two various issues caused by doing that, but today I hit something a bit more vital and decided to find exactly what the cause is.
Through testing I've narrowed down the code as much as possible, and I've found it's when attempting to get the parent of shiboken2.wrapInstance. Attempting to create the window after that comes up with an error saying RuntimeError: Internal C++ object (PySide2.QtWidgets.QWidget) already deleted..
import maya.OpenMayaUI as omUI
import pymel.core as pm
import shiboken2
from PySide2 import QtWidgets
win_id = 'test'
#Delete existing window
if pm.workspaceControl(win_id, exists=True):
pm.deleteUI(win_id)
#Create window and setup wrapper
pm.workspaceControl(win_id)
c_pointer = omUI.MQtUtil.findControl(win_id)
parent_wrap = shiboken2.wrapInstance(int(c_pointer), QtWidgets.QWidget)
print parent_wrap.parent()
#Create actual window
#This will error if parent_wrap.parent() was called
win = QtWidgets.QMainWindow(parent_object)
How could I get the parent of the wrap instance without causing issues? I assume it's something to do with unreferencing things from memory prematurely, but I'm not sure how I could go about fixing it.

I found a fix that is kinda dirty but seems to work reliably so far.
So to start with I found if you create two instances of the above parent_wrap, and get the parent before you create the second one, it's possible to pass into the window separately without causing issues. It works up until the point the window is docked/detached, but that deletes the old parents and provides new ones, so the old pointer is no longer valid.
It seemed that providing this parent before the window being initialised allowed me to then regerate it with self.parent().parent().... without breaking the code.
It needs to be updated if the state has changed (floating/docked), and whenever a RuntimeError occurs, but as it's not going to be a huge hit in performance, for simplicity I'm just regenerating it each time it is needed.
To override a function, like move for example, this would be how to use it:
def move(self, x, y):
if self.dockable:
return self._parent_override().move(x, y)
return QtWidgets.QMainWindow.move(self, x, y)
And this is the override class to solve the issue:
def _parent_override(self, create=True):
#Determine if it's a new window, we need to get the C++ pointer again
if not hasattr(self, '__temp_parent'):
base = qt_get_window(self.ID)
else:
base = self.parent()
#Get the correct parent level
if pm.workspaceControl(self.ID, query=True, floating=True):
parent = base.parent().parent().parent().parent()
else:
parent = base.parent().parent()
#Even though this attribute is never used,
#PySide2 is dumb and deletes the parent if it's not set
self.__temp_parent = parent
return parent

PyCharm / PyQt: How to obtain code completion with dynamically loaded ui files

Let's say I have a ui file created in Qt Designer that I want to load dynamically to then manipulate the widgets, such as:
example.py:
from PyQt5 import QtWidgets, uic
class MyWidget(QtWidgets.QWidget):
def __init__(self, parent=None):
super(MyWidget, self).__init__(parent)
uic.loadUi('example.ui', self)
# No code completion here for self.myPushButton:
self.myPushButton.clicked.connect(self.handleButtonClick)
self.show()
Is there a standard / convenient way of enabling code completion for the widgets loaded this way in PyCharm (2017.1.4)?
At the moment I am using this (written in the constructor after the ui file is loaded):
self.myPushButton = self.myPushButton # type: QtWidgets.QPushButton
# Code completion for myPushButton works at this point
I also thought of this, but it does not seem to do the trick:
assert isinstance(self.myPushButton, QtWidgets.QPushButton)
# PyCharm does not even recognise myPushButton as an attribute of self at this point
Finally, I also thought of using python stubs, such as:
example.pyi:
class MyWidget(QtWidgets.QWidget):
def __init__(self):
self.myPushButton: QtWidgets.QPushButton = ...
However, myPushButton is properly recognised in code outside example.py but not in code inside example.py itself, which is kind of the opposite of what I wanted.
I am also considering taking my first approach but with all those lines put in a private method that will never get called, such as:
example.py:
from PyQt5 import QtWidgets, uic
class MyWidget(QtWidgets.QWidget):
def __init__(self, parent=None):
super(MyWidget, self).__init__(parent)
uic.loadUi('example.ui', self)
# Code completion now works here for self.myPushButton:
self.myPushButton.clicked.connect(self.handleButtonClick)
self.show()
def __my_private_method_never_called():
self.myPushButton = self.myPushButton # type: QtWidgets.QPushButton
# Or even this (it should have the same effect if this
# function is never called, plus it is less verbose):
self.myPushButton = QtWidgets.QPushButton()
# If I want to make sure that this is never called
# could raise an error at some point:
raise YouShouldNotHaveCalledThisError()
This seems to work fine, and it also allows me to group all my type hinting code together, isolated from the rest. I could even make some script to write all those lines for me by parsing the ui files. I am just wondering if people reading my code would find this approach very unorthodox, even if I comment clearly why am I writing a technically useless private function.

If anybody is interested, I made the script I mentioned to parse the .ui files and generate stub code ready to be copied to my class:
ui_stub_generator.py:
from __future__ import print_function
import os
import sys
import xml.etree.ElementTree
def generate_stubs(file):
root = xml.etree.ElementTree.parse(file).getroot()
print('Stub for file: ' + os.path.basename(file))
print()
print(' def __stubs(self):')
print(' """ This just enables code completion. It should never be called """')
for widget in root.findall('.//widget'):
name = widget.get('name')
if len(name) > 3 and name[:2] == 'ui' and name[2].isupper():
cls = widget.get('class')
print(' self.{} = QtWidgets.{}()'.format(
name, cls
))
print(' raise AssertionError("This should never be called")')
print()
def main():
for file in sys.argv[1:]:
generate_stubs(file)
if __name__ == '__main__':
main()
This only parses widgets whose names start with 'ui' followed by an uppercase letter, such as 'uiMyWidget', which is the naming convention that I typically follow in the Qt Designer. By doing this, the widgets with names automatically generated by the Qt Designer are ignored (if I cared about these, I would have given them a proper name). It should be straightforward to update this for any other naming conventions, or other type of objects, such as actions.
For convenience, I have set this up as an external tool in PyCharm as well; see screenshot here (change the paths as appropriate). That way, I only have to right-click my ui file in the project window, then External Tools -> Stub Generator for Qt UI Files, and I get the following output in the Run window ready to be copied:
C:\ProgramData\Anaconda3\python.exe D:\MyProject\bin\ui_stub_generator.py D:\MyProject\my_ui_file.ui
Stub for file: my_ui_file.ui
def __stubs(self):
""" This just enables code completion. It should never be called """
self.uiNameLabel = QtWidgets.QLabel()
self.uiOpenButton = QtWidgets.QPushButton()
self.uiSplitter = QtWidgets.QSplitter()
self.uiMyCombo = QtWidgets.QComboBox()
self.uiDeleteButton = QtWidgets.QPushButton()
raise AssertionError("This should never be called")
Process finished with exit code 0

Getting, Storing, Setting and Modifying Transform Attributes through PyMel

I'm working on something that gets and stores the transforms of an object moved by the user and then allows the user to click a button to return to the values set by the user.
So far, I have figured out how to get the attribute, and set it. However, I can only get and set once. Is there a way to do this multiple times within the script running once? Or do I have to keep rerunning the script? This is a vital question for me get crystal clear.
basically:
btn1 = button(label="Get x Shape", parent = layout, command ='GetPressed()')
btn2 = button(label="Set x Shape", parent = layout, command ='SetPressed()')
def GetPressed():
print gx #to see value
gx = PyNode( 'object').tx.get() #to get the attr
def SetPressed():
PyNode('object').tx.set(gx) #set the attr???
I'm not 100% on how to do this correctly, or if I'm going the right way?
Thanks

You aren't passing the variable gx so SetPressed() will fail if you run it as written(it might work sporadically if you tried executing the gx = ... line directly in the listener before running the whole thing -- but it's going to be erratic). You'll need to provide a value in your SetPressed() function so the set operation has something to work with.
As an aside, using string names to invoke your button functions isn't a good way to go -- you code will work when executed from the listener but will not work if bundled into a function: when you use a string name for the functions Maya will only find them if they live the the global namespace -- that's where your listener commands go but it's hard to reach from other functions.
Here's a minimal example of how to do this by keeping all of the functions and variables inside another function:
import maya.cmds as cmds
import pymel.core as pm
def example_window():
# make the UI
with pm.window(title = 'example') as w:
with pm.rowLayout(nc =3 ) as cs:
field = pm.floatFieldGrp(label = 'value', nf=3)
get_button = pm.button('get')
set_button = pm.button('set')
# define these after the UI is made, so they inherit the names
# of the UI elements
def get_command(_):
sel = pm.ls(sl=True)
if not sel:
cmds.warning("nothing selected")
return
value = sel[0].t.get() + [0]
pm.floatFieldGrp(field, e=True, v1= value[0], v2 = value[1], v3 = value[2])
def set_command(_):
sel = pm.ls(sl=True)
if not sel:
cmds.warning("nothing selected")
return
value = pm.floatFieldGrp(field, q=True, v=True)
sel[0].t.set(value[:3])
# edit the existing UI to attech the commands. They'll remember the UI pieces they
# are connected to
pm.button(get_button, e=True, command = get_command)
pm.button(set_button, e=True, command = set_command)
w.show()
#open the window
example_window()
In general, it's this kind of thing that is the trickiest bit in doing Maya GUI -- you need to make sure that all the functions and handlers etc see each other and can share information. In this example the function shares the info by defining the handlers after the UI exists, so they can inherit the names of the UI pieces and know what to work on. There are other ways to do this (Classes are the most sophisticated and complex) but this is the minimalist way to do it. There's a deeper dive on how to do this here