CODEWITHSUNDEEP
pythonqtpyqtpyside
alphanumeric
alphanumeric

Reputation: 19329

How to contol KeyEvent in Qt

enter image description here

With the window declared with CustomWidget as super class: class App(CustomWidget) hitting Alt+A properly prints 'keyPressEvent: Alt + a' message.

But the KeyEvent functionality is broken when the CustomWidget is assigned to window with setCentralWidget() or is set with layer.addWidget(widget). What is missing in a code?

from PyQt4 import QtCore, QtGui

class CustomWidget(QtGui.QWidget):
    def __init__(self, parent):
        QtGui.QWidget.__init__(self, parent=parent)

    def keyPressEvent(self, event):
        if event.modifiers() == QtCore.Qt.AltModifier:
            if event.key() == QtCore.Qt.Key_A:
                print 'keyPressEvent: Alt + a'
        # super(CustomWidget, self).keyPressEvent(event)

class App(QtGui.QMainWindow):
    def __init__(self, parent=None):
        QtGui.QMainWindow.__init__(self, parent=parent) 
        centralWidget = CustomWidget(self) 

        self.setCentralWidget(centralWidget)

        mainLayout=QtGui.QVBoxLayout()
        centralWidget.setLayout(mainLayout)

        widget = CustomWidget(self)
        mainLayout.addWidget(widget)

if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    w = App()
    w.show()
    sys.exit(app.exec_())

Upvotes: 0

Views: 373

Answers (2)

alphanumeric
alphanumeric

Reputation: 19329

Working Solution:

Important: At the end of GroupBox' keyPressEvent() method we have to pass the Event up to the super. Or the Event will not get propagated to the parent widget: super(QtGui.QGroupBox, self).keyPressEvent(event)

enter image description here

import sys
from PyQt4 import QtCore, QtGui

class MainWindow(QtGui.QMainWindow):
    def __init__(self, parent):
        QtGui.QMainWindow.__init__(self, parent=parent)
        self.setFocusPolicy(QtCore.Qt.StrongFocus) 

    def keyPressEvent(self, event):
        if event.modifiers() == QtCore.Qt.ControlModifier:
            if event.key() == QtCore.Qt.Key_T:
                print 'MainWindow: Control + t'
            if event.key() == QtCore.Qt.Key_M:
                print 'MainWindow: Control + m'

class GroupBox(QtGui.QGroupBox):
    def __init__(self, parent=None):
        QtGui.QGroupBox.__init__(self, parent=parent)
        self.setFocusPolicy(QtCore.Qt.StrongFocus) 

    def keyPressEvent(self, event):
        if event.modifiers() == QtCore.Qt.ControlModifier:
            if event.key() == QtCore.Qt.Key_T:
                print 'GroupBox: Control + t'
            if event.key() == QtCore.Qt.Key_S:
                print 'GroupBox: Control + s'
        super(QtGui.QGroupBox, self).keyPressEvent(event)

class App(MainWindow):
    def __init__(self, parent=None):
        MainWindow.__init__(self, parent=parent) 
        centralWidget = QtGui.QWidget(self) 

        self.setCentralWidget(centralWidget)

        mainLayout=QtGui.QVBoxLayout()
        centralWidget.setLayout(mainLayout)

        groupBox = GroupBox(self)
        mainLayout.addWidget(groupBox)

if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    w = App()
    w.show()
    sys.exit(app.exec_())

Upvotes: 0

PowerGlove
PowerGlove

Reputation: 177

The widget must have focus to receive the event. Make sure you call setFocusPolicy() to have the CustomWidget accept and maintain focus after creating the window.

QWidget, keyPressEvent

QWidget, setFocusPolicy

Upvotes: 1

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