Today’s goal is to run pip command and install library in the environment of Google Colaboratory.
Reference: Importing a library that is not in Colaboratory
To execute shell command in Google Colaboratory, put ! at the top of the script.
!pip install matplotlib-venn
Today’s goal is to execute a function when QTreeWidgetItem is double clicked.
Windows 10
Python 3.8.7
PySide2 (5.15.2)
First I created a sample QTreeWidget as below.
import sys
from PySide2.QtWidgets import *
class MyMainWindow(QMainWindow):
def __init__(self, parent=None):
super(MyMainWindow, self).__init__(parent)
self._generate_ui()
self._init_tree_widget()
def _generate_ui(self):
main_widget = QWidget()
main_layout = QVBoxLayout()
main_widget.setLayout(main_layout)
self.setCentralWidget(main_widget)
self.tree_widget = QTreeWidget()
self.tree_widget.setSelectionMode(QAbstractItemView.ExtendedSelection)
self.tree_widget.setSelectionBehavior(QAbstractItemView.SelectItems)
main_layout.addWidget(self.tree_widget)
def _init_tree_widget(self):
headers = ["header1", "header2"]
self.tree_widget.setHeaderLabels(headers)
tree_widget_item1 = QTreeWidgetItem(["group1"])
tree_widget_item1.addChild(QTreeWidgetItem(["item1_1", "item1_2"]))
self.tree_widget.addTopLevelItem(tree_widget_item1)
tree_widget_item2 = QTreeWidgetItem(["group2"])
self.tree_widget.addTopLevelItem(tree_widget_item2)
tree_widget_item2.addChild(QTreeWidgetItem(["item2_1", "item2_2"]))
tree_widget_item2.addChild(QTreeWidgetItem(["item3_1", "item3_2"]))
def launch():
app = QApplication.instance()
if not app:
app = QApplication(sys.argv)
widget = MyMainWindow()
widget.show()
app.exec_()
launch()Connect the function to QTreeWidget.itemDoubleClicked signal.
class MyMainWindow(QMainWindow):
def __init__(self, parent=None):
# omitted
def _generate_ui(self):
main_widget = QWidget()
main_layout = QVBoxLayout()
main_widget.setLayout(main_layout)
self.setCentralWidget(main_widget)
self.tree_widget = QTreeWidget()
self.tree_widget.setSelectionMode(QAbstractItemView.ExtendedSelection)
self.tree_widget.setSelectionBehavior(QAbstractItemView.SelectItems)
self.tree_widget.itemDoubleClicked.connect(self._doubleClicked) # connect function to the signal itemDoubleClicked
main_layout.addWidget(self.tree_widget)
def _init_tree_widget(self):
# omitted
def _doubleClicked(self): # this function is executed when an item is double clicked
print("double clicked")Use QTreeWidget.currentItem(), QTreeWidget.currentColumn() or QAbstractItemView.currentIndex().
def _doubleClicked(self):
column = self.tree_widget.currentColumn()
text = self.tree_widget.currentItem().text(column)
print("double clicked item is " + text)
# output when item1_2 clicked => double clicked item is item1_2
# output when group1 clicked => double clicked item is grounp1I’d like to clear and redraw widgets in my custom PySide2 UI.
Today’s goal is to remove and delete all children widgets from the layout.
Windows 10
Python 3.8.7
PySide2 (5.15.2)
I created sample widget with clear-all button.
import sys
from PySide2.QtWidgets import *
from PySide2.QtCore import Qt, QEventLoop
class MyWidget(QWidget):
def __init__(self, parent=None):
super(MyWidget, self).__init__(parent)
self.main_layout = QVBoxLayout()
self.setLayout(self.main_layout)
self._generateUI()
def _generateUI(self):
clear_button = QPushButton("Clear All")
clear_button.clicked.connect(self._clearall)
self.main_layout.addWidget(clear_button)
label = QLabel("Label")
self.main_layout.addWidget(label)
combobox = QComboBox()
combobox.addItems(["comboBox1", "comboBox2"])
self.main_layout.addWidget(combobox)
buttons_widget = QWidget()
buttons_layout = QHBoxLayout()
buttons_widget.setLayout(buttons_layout)
for i in range(3):
button = QPushButton("button"+str(i))
buttons_layout.addWidget(button)
self.main_layout.addWidget(buttons_widget)
def _clearall(self): # the function to clear widgets
pass
if __name__ == '__main__':
app = QApplication(sys.argv)
widget = MyWidget()
widget.show()
sys.exit(app.exec_())To get the list of children in the layout, use count() and itemAt(). Because the itemAt() function returns QLayoutItem not Qwidget, we should get widget by using QLayoutItem.widget() method.
def _clearall(self):
children = []
for i in range(self.main_layout.count()):
child = self.main_layout.itemAt(i).widget()
if child:
children.append(child)
print(child)
# output
# <class 'PySide2.QtWidgets.QPushButton'>
# <class 'PySide2.QtWidgets.QLabel'>
# <class 'PySide2.QtWidgets.QComboBox'>
# <class 'PySide2.QtWidgets.QWidget'>Use deleteLater() to delete widget.
def _clearall(self):
children = []
for i in range(self.main_layout.count()):
child = self.main_layout.itemAt(i).widget()
if child:
children.append(child)
for child in children:
child.deleteLater()* There are many ways to remove widget from the parent layout. For example, some people use setParent(None) or something. However don’t use removeWidget() because it just removes widget without destroying it. Please refer to the discussion below.
There are another methods to implement _clearall() function.
It works well because the deleteLater() destroys items after returning control from the function.
def _clearall(self):
for i in range(self.main_layout.count()):
child = self.main_layout.itemAt(i).widget()
child.widget().deleteLater()This is a wrong example. The itemAt() function can’t find the child because when an item is deleted with setParent(None), other items will be renumbered.
def _clearall(self): #wrong example
for i in range(self.main_layout.count()):
child = self.main_layout.itemAt(i).widget()
child.setParent(None)
# An error occurred: AttributeError: 'NoneType' object has no attribute 'widget'You can get children of widget with children() function.
def _clearall_4(self): #wrong
for child in self.children():
print(child.__class__)
child.deleteLater()
# output
# <class 'PySide2.QtWidgets.QVBoxLayout'> # children() returns layout too
# <class 'PySide2.QtWidgets.QPushButton'>
# <class 'PySide2.QtWidgets.QLabel'>
# <class 'PySide2.QtWidgets.QComboBox'>
# <class 'PySide2.QtWidgets.QWidget'>You can get children of widget with findChild() function.
def _clearall_4(self): #wrong
for child in self.findChildren(QWidget):
print(child.__class__)
child.deleteLater()
# output
# <class 'PySide2.QtWidgets.QPushButton'>
# <class 'PySide2.QtWidgets.QLabel'>
# <class 'PySide2.QtWidgets.QComboBox'>
# <class 'PySide2.QtWidgets.QWidget'>
# <class 'PySide2.QtWidgets.QPushButton'>
# <class 'PySide2.QtWidgets.QPushButton'>
# <class 'PySide2.QtWidgets.QPushButton'>
This is a wrong example. The children() of layout returns [].
def _clearall_4(self): #wrong example
for child in self.main_layout.children():
child.deleteLator()
print("first layout children", self.main_layout.children()) # output => []Today’s goal is to create On/Off button in my PySide UI as below.
Windows 10
Python 3.8.7
PySide2 (5.15.2)
import sys
from PySide2.QtWidgets import *
class MyWidget(QWidget):
def __init__(self):
super(MyWidget, self).__init__()
self.layout = QVBoxLayout()
self.on_off_button = QPushButton("on/off Button")
self.on_off_button.setCheckable(True)
#self.layout.addWidget(self.on_off_button)
self.setLayout(self.layout)
if __name__ == '__main__':
app = QApplication(sys.argv)
widget = MyWidget()
widget.show()
sys.exit(app.exec_())
QAbstractButton has a method setCheckable().
class MyWidget(QWidget):
def __init__(self):
super(MyWidget, self).__init__()
self.layout = QVBoxLayout()
self.on_off_button = QPushButton("on/off Button")
self.on_off_button.setCheckable(True) # set Checkable True
self.layout.addWidget(self.on_off_button)
self.setLayout(self.layout)To change the status manually, use the setChecked() method of QAbstractButton.
For example, reset button can be implemented by using the function to set the button unchecked.
class MyWidget(QWidget):
def __init__(self):
super(MyWidget, self).__init__()
self.layout = QGridLayout()
self.reset_button = QPushButton("Reset")
self.reset_button.clicked.connect(self._reset)
self.layout.addWidget(self.reset_button,0,0,1,3)
self.on_off_button1 = QPushButton("on/off 1")
self.on_off_button1.setCheckable(True)
self.layout.addWidget(self.on_off_button1,1,0,1,1)
self.on_off_button2 = QPushButton("on/off 2")
self.on_off_button2.setCheckable(True)
self.layout.addWidget(self.on_off_button2,1,1,1,1)
self.on_off_button3 = QPushButton("on/off 3")
self.on_off_button3.setCheckable(True)
self.layout.addWidget(self.on_off_button3,1,2,1,1)
self.setLayout(self.layout)
def _reset(self):
self.on_off_button1.setChecked(False)
self.on_off_button2.setChecked(False)
self.on_off_button3.setChecked(False)
To get object name from the object.
Python 3.8.7
Use special attributes “__class__” of the object.
f = open('test.txt', 'r')
# getting class name
print(f.__class__.__name__)
#output => TextIOWrapper
# getting the module where the class is defined
print(f.__class__.__module__)
#output => _io
f.close()Reference: Special Attributes
To import modules by its name as below.
def import_n_th_module(index):
"""
the function to get index number and import the module named mymodule+index such as mymodule1, mymodule2,...
"""
module_name = 'mymodule' + str(index)
# import module_name => the error occuredPython 3.8.7
The purpose of the importlib package is two-fold. One is to provide the implementation of the import statement (and thus, by extension, the import() function) in Python source code. <omit>
from importlib — The implementation of import of Python documentaion
You can import module with importlib.import_module() as follows.
importlib.import_module('numpy')
# output => import numpy moduleI created 3 modules in modules package. And each module prints “[module_name] is imported” when being imported.
#test.py
import sys
import importlib
index = 3
importlib.import_module('modules.mymodule' + str(index))
# output => "mymodule3 is imported"Two, the components to implement import are exposed in this package, making it easier for users to create their own custom objects (known generically as an importer) to participate in the import process.
from importlib — The implementation of import of Python documentaion
You can see all methods of importlib in importlib — The implementation of import of Python documentaion.
This is a part of the project “Easy Keymap Generator”.
To implement a function that get keyconfig name and return keyconfig object.
The list of keyconfig names can be seen in Preferences window.
Blender 2.83 (Python 3.7.4)
Windows 10
This is my solution, but I don’t think it is the best way. Please let me know if you have any better ideas.
def get_keyconfig(keyconfig_name):
wm = bpy.context.window_manager
if keyconfig_name in wm.keyconfigs.keys():
return wm.keyconfigs[keyconfig_name]
else:
return NoneIf there is no keyconfig you’d like to get in current environment, you should activate the keyconfig by its path manually.
key_config_dict = get_keyconfig_dict()
configs = list(key_config_dict.keys())
print(configs)
# output => ['blender', 'blender_27x', 'industry_compatible', 'test1', 'test2']
kc = get_keyconfig(configs[1], key_config_dict)
print(kc)
# output => blender_27x <bpy_struct, KeyConfig("blender_27x")>I created a function to get the dict with keys of keyconfig name and values of path to the keyconfig python file.
Reference: How to get key config list in Blender Python
def get_keyconfigs():
"""
:return: dict{kerconfig_name(str): path to config file(str)}
"""
config_pathes = bpy.utils.preset_paths("keyconfig")
config_dict = {}
for config_path in config_pathes:
for file in os.listdir(config_path):
name, ext = os.path.splitext(file)
if ext.lower() in [".py", ".xml"] and not name[0] == ".":
config_dict[name] = os.path.join(config_path, file)
return config_dictActivate the specified keyconfig by its path and get active keyconfig with wm.keyconfigs.active then restore active keyconfig to original settings.
def get_keyconfig(keyconfig_name, keyconfig_dict):
wm = bpy.context.window_manager
if keyconfig_name in wm.keyconfigs.keys(): #if the keyconfig can be found, return it
return wm.keyconfigs[keyconfig_name]
else: # activate by config path and return it
keyconfig_path = keyconfig_dict[keyconfig_name]
current_path = keyconfig_dict[wm.keyconfigs.active.name]
bpy.ops.preferences.keyconfig_activate(filepath=keyconfig_path)
kc = wm.keyconfigs.active
bpy.ops.preferences.keyconfig_activate(filepath=current_path)
return kcThis is a part of the project “Easy Keymap Generator”.
To get the key config list in my addon. The list of key configs can be seen in Preferences window.
Blender 2.83 (Python 3.7.4)
Windows 10
Get the list directly from the preset directories.
Related article: How to get preset paths in Blender Python
def get_keyconfigs():
"""
:return: dict{kerconfig_name(str): path to config file(str)}
"""
config_pathes = bpy.utils.preset_paths("keyconfig")
config_dict = {}
for config_path in config_pathes:
for file in os.listdir(config_path):
name, ext = os.path.splitext(file)
if ext.lower() in [".py", ".xml"] and not name[0] == ".":
config_dict[name] = os.path.join(config_path, file)
return config_dict
print(key_config_dict.keys())
#output => dict_keys(['blender', 'blender_27x', 'industry_compatible', 'test1', 'test2'])This is a tips for blender addon developers.
To get the list of paths to preset directories, blender system preset and user preset and so on.
These are examples of the preset directory.
Blender 2.83 (Python 3.7.4)
Windows 10
Use bpy.utils.preset_paths(subdir) that returns the list of paths to the preset directory of subdir.
(more…)I’d like to add close button to the single widget and remove the widget from the parent layout when the close button pressed.
To remove single widget with close button as below.
Windows 10
Python 3.8.7
PySide2 5.15.2
I create ItemWidget with close button and put the item and add button on the main window. Check “How To Insert Widget To The Layout Counting From The End” for detail about the implement of add button.
import sys
from PySide2.QtWidgets import *
class ItemWidget(QWidget):
def __init__(self, id_str="", parent=None):
super(ItemWidget, self).__init__(parent)
self.id_str = id_str
self._generateUI()
def _generateUI(self):
main_layout = QGridLayout()
self.setLayout(main_layout)
title = QLabel("title" + self.id_str)
main_layout.addWidget(title, 0, 0, 1, 3)
close_button = QPushButton("-")
close_button.setFixedWidth(30)
main_layout.addWidget(close_button, 0, 3, 1, 1)
spinbox = QSpinBox()
main_layout.addWidget(spinbox, 1, 0, 1, 4)
class MyMainWindow(QMainWindow):
def __init__(self, parent=None):
super(MyMainWindow, self).__init__(parent)
self.id_num = 1
self._generateUI()
def _generateUI(self):
main_widget = QWidget()
self.main_layout = QVBoxLayout()
main_widget.setLayout(self.main_layout)
self.setCentralWidget(main_widget)
item = ItemWidget(str(self.id_num))
self.main_layout.addWidget(item)
add_button = QPushButton("+")
add_button.clicked.connect(self._addItem)
self.main_layout.addWidget(add_button)
def _addItem(self):
self.id_num += 1
item = ItemWidget(str(self.id_num))
self.main_layout.insertWidget(self.main_layout.count()-1, item)
def launch():
app = QApplication.instance()
if not app:
app = QApplication(sys.argv)
widget = MyMainWindow()
widget.show()
app.exec_()
launch()Use deleteLater() to delete widget.
class ItemWidget(QWidget):
def __init__(self, id_str="", parent=None):
super(ItemWidget, self).__init__(parent)
self.id_str = id_str
self._generateUI()
def _generateUI(self):
main_layout = QGridLayout()
self.setLayout(main_layout)
title = QLabel("title" + self.id_str)
main_layout.addWidget(title, 0, 0, 1, 3)
close_button = QPushButton("-")
close_button.setFixedWidth(30)
close_button.clicked.connect(self._close_widget) # add to close the widget
main_layout.addWidget(close_button, 0, 3, 1, 1)
spinbox = QSpinBox()
main_layout.addWidget(spinbox, 1, 0, 1, 4)
def _close_widget(self):
self.deleteLater() # main function to close widget
* There are many ways to remove widget from the parent layout. For example, some people use setParent(None) or something. However don’t use removeWidget() because it just removes widget without destroying it. Please refer to the discussion below.
The function deleteLater() just delete the widget without changing the size. So I changed size manually with adjustSize() as below.
Related article: How to detect the child widget destroy?
class MyMainWindow(QMainWindow):
def __init__(self, parent=None):
super(MyMainWindow, self).__init__(parent)
self.id_num = 1
self._generateUI()
def _generateUI(self):
main_widget = QWidget()
self.main_layout = QVBoxLayout()
main_widget.setLayout(self.main_layout)
self.setCentralWidget(main_widget)
item = ItemWidget(str(self.id_num))
self.main_layout.addWidget(item)
add_button = QPushButton("+")
add_button.clicked.connect(self._addItem)
self.main_layout.addWidget(add_button)
def _addItem(self):
self.id_num += 1
item = ItemWidget(str(self.id_num))
self.main_layout.insertWidget(self.main_layout.count()-1, item)
def _deletedItem(self, item):
self.id_num -= 1
for i in range(3):
QApplication.processEvents()
self.adjustSize()I don’t know why but adjustSize() doesn’t work correctly until some events are processed in the event loop. So I called QApplication.processEvents() in the for loop. Please let me know if you have any idea about this
Reference: PySide: What is the best way to resize the main window if one widget is hidden? in stackoverflow.com