Pyside2 bind key to a method call and not to button or menu

Question

I am trying to bind a key directly to a method call. I have found this solution but it binds the key to a button:

How do I make a shortcut using arrow key with PySide2?

When I try to bind it to a method like this:

QtWidgets.QShortcut(QtGui.QKeySequence(QtCore.Qt.LeftArrow), self.my_function)

Errors are thrown:

TypeError: 'PySide2.QtWidgets.QShortcut' called with wrong argument types:
  PySide2.QtWidgets.QShortcut(QKeySequence, method)
Supported signatures: ......

Code example:

from PySide2 import QtCore, QtWidgets, QtUiTools, QtGui
import sys
class mainW(QtCore.QObject):
    def __init__(self):    
        super(mainW, self).__init__()
        self.init_ui()
        self.init_connections()
        self.ui.show()

    def init_ui(self):
        file = QtCore.QFile("ressource_files/energiebericht_pruefung_main.ui")
        file.open(QtCore.QFile.ReadOnly)
        loader = QtUiTools.QUiLoader()
        self.ui = loader.load(file)

    def init_connections(self):
        QtWidgets.QShortcut(QtGui.QKeySequence(QtCore.Qt.LeftArrow), self.my_function)

    def my_function(self):
        print('* MY FUNCTION HAS BEEN CALLED *')

# MAIN
app = QtWidgets.QApplication(sys.argv)
w = mainW()
sys.exit(app.exec_())

Corresponding ui-file:

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>1394</width>
    <height>726</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Energiebericht Prüfung</string>
  </property>
  <widget class="QWidget" name="centralwidget">
   <layout class="QGridLayout" name="gridLayout_4">
    <item row="0" column="0">
     <widget class="QGroupBox" name="groupBox">
      <property name="maximumSize">
       <size>
        <width>200</width>
        <height>16777215</height>
       </size>
      </property>
      <property name="title">
       <string>Infrastrukturelement</string>
      </property>
      <layout class="QGridLayout" name="gridLayout">
       <item row="0" column="0">
        <widget class="QListWidget" name="lwISE"/>
       </item>
      </layout>
     </widget>
    </item>
    <item row="0" column="1">
     <widget class="QGroupBox" name="groupBox_2">
      <property name="maximumSize">
       <size>
        <width>200</width>
        <height>16777215</height>
       </size>
      </property>
      <property name="title">
       <string>Profil</string>
      </property>
      <layout class="QGridLayout" name="gridLayout_2">
       <item row="0" column="0">
        <widget class="QListWidget" name="lwProfil"/>
       </item>
      </layout>
     </widget>
    </item>
    <item row="0" column="2">
     <widget class="QGroupBox" name="groupBox_3">
      <property name="title">
       <string>Chart</string>
      </property>
      <layout class="QGridLayout" name="gridLayout_3">
       <item row="0" column="0">
        <widget class="QStackedWidget" name="stackedWidget">
         <property name="currentIndex">
          <number>0</number>
         </property>
         <widget class="QWidget" name="gfx1"/>
         <widget class="QWidget" name="gfx2"/>
        </widget>
       </item>
      </layout>
     </widget>
    </item>
    <item row="1" column="0" colspan="3">
     <widget class="QTableWidget" name="tW">
      <property name="maximumSize">
       <size>
        <width>16777215</width>
        <height>140</height>
       </size>
      </property>
      <property name="rowCount">
       <number>3</number>
      </property>
      <property name="columnCount">
       <number>13</number>
      </property>
      <row/>
      <row/>
      <row/>
      <column/>
      <column/>
      <column/>
      <column/>
      <column/>
      <column/>
      <column/>
      <column/>
      <column/>
      <column/>
      <column/>
      <column/>
      <column/>
     </widget>
    </item>
   </layout>
  </widget>
  <widget class="QMenuBar" name="menubar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>1394</width>
     <height>21</height>
    </rect>
   </property>
  </widget>
  <widget class="QStatusBar" name="statusbar"/>
 </widget>
 <resources/>
 <connections/>
</ui>

Answer 1

A QShorcut is associated with a QWidget, therefore it throws you that error, you must also use "left" in the QKeySequence since QKeySequence does not support Qt::Key alone but with modifiers.

import os
import sys
from PySide2 import QtCore, QtWidgets, QtUiTools, QtGui


CURRENT_DIR = os.path.dirname(os.path.realpath(__file__))


class mainW(QtCore.QObject):
    def __init__(self):
        super(mainW, self).__init__()
        self.init_ui()
        self.init_connections()
        self.ui.show()

    def init_ui(self):
        filename = os.path.join(
            CURRENT_DIR, "ressource_files/energiebericht_pruefung_main.ui"
        )
        file = QtCore.QFile(filename)
        if not file.open(QtCore.QFile.ReadOnly):
            sys.exit(-1)
        loader = QtUiTools.QUiLoader()
        self.ui = loader.load(file)

    def init_connections(self):
        QtWidgets.QShortcut(QtGui.QKeySequence("left"), self.ui, self.my_function)

    @QtCore.Slot()
    def my_function(self):
        print("* MY FUNCTION HAS BEEN CALLED *")


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    w = mainW()
    sys.exit(app.exec_())