在QWidget中实现keyPressEvent

Question

我有一个带有继续按钮的QDialog窗口。继续按钮是默认按钮，因为每当我按下Enter键时，都会按下继续按钮。我发现了一些奇怪的事情：当我按Enter键三下时，继续按钮也按了三下。但是，当我第四次按下它时，整个窗口关闭。我在关闭窗口的继续按钮下面有一个取消按钮，但是我没有将取消按钮设置为默认按钮或其他任何按钮。

我想覆盖它，keyPressEvent以便每当我进入窗口时，输入按钮将始终连接到继续按钮。

这就是我现在所拥有的：

class ManualBalanceUI(QtGui.QWidget):
    keyPressed = QtCore.pyqtSignal()

    def __init__(self, cls):
        super(QtGui.QWidget, self).__init__()
        self.window = QtGui.QDialog(None, QtCore.Qt.WindowSystemMenuHint)
        self.ui = uic.loadUi('ManualBalanceUI.ui', self.window)
        self.keyPressed.connect(self.on_key)

    def keyPressEvent(self, event):
        super(ManualBalanceUI, self).keyPressEvent(event)
        self.keyPressed.emit(event) 

    def on_key(self, event):
        if event.key() == QtCore.Qt.Key_Enter and self.ui.continueButton.isEnabled():
            self.proceed()  # this is called whenever the continue button is pressed
        elif event.key() == QtCore.Qt.Key_Q:
            self.window.close()  # a test I implemented to see if pressing 'Q' would close the window
     def proceed(self):
         ...
     ...

但是，这似乎现在没有做任何事情。按下“ Q”不会关闭窗口，而且我无法真正确定“ enter”键是否起作用。

我事先看过这个问题：PyQt Connect to KeyPressEvent

我还查看了SourceForge上的所有文档。任何帮助将不胜感激！

Answer 1

您可以采用两种方法，一种是简单地重新实现keyPressevent而不进行任何花哨的工作。像这样

from PyQt4 import QtCore, QtGui
import sys

class Example(QtGui.QWidget):
    def __init__(self):
        super(Example, self).__init__()
        self.setGeometry(300, 300, 250, 150)
        self.show()

    def keyPressEvent(self, event):
        if event.key() == QtCore.Qt.Key_Q:
            print "Killing"
            self.deleteLater()
        elif event.key() == QtCore.Qt.Key_Enter:
            self.proceed()
        event.accept()

    def proceed(self):
        print "Call Enter Key"

def main():
    app = QtGui.QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()

或者，当您尝试使用信号时，如果是缺少正确实施此信号的情况，则此处为更新版本。

class Example(QtGui.QWidget):
    keyPressed = QtCore.pyqtSignal(QtCore.QEvent)
    def __init__(self):
        super(Example, self).__init__()
        self.setGeometry(300, 300, 250, 150)
        self.show()
        self.keyPressed.connect(self.on_key)

    def keyPressEvent(self, event):
        super(Example, self).keyPressEvent(event)
        self.keyPressed.emit(event) 

    def on_key(self, event):
        if event.key() == QtCore.Qt.Key_Enter and self.ui.continueButton.isEnabled():
            self.proceed()  # this is called whenever the continue button is pressed
        elif event.key() == QtCore.Qt.Key_Q:
            print "Killing"
            self.deleteLater()  # a test I implemented to see if pressing 'Q' would close the window

    def proceed(self):
        print "Call Enter Key"

def main():
    app = QtGui.QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()

Answer 2

如果您在 2019 年查看此内容，并且 Achayan 的方法不适合您，那么请检查以下几件事：

1) keyPressEvent 是否在主窗口或主窗口小部件的子窗口中被覆盖？子函数将覆盖父函数的方法（至少在使用带有 setCentralWidget 的 QMainWindow 时）。如果是这种情况，那么信号可能不会像您期望的那样发出

2) 您是否有一个与 QWidget 不同的处理按键输入的小部件？例如，如果焦点位于 QTextEdit 对象中，则按键输入将不会发送到 keyPressEvent。将焦点转移到另一个小部件

例如，观察以下输出：

class myDialog(QtWidgets.QDialog):
    keyPressed = QtCore.pyqtSignal(QtCore.QEvent)

    def __init__(self, parent=None):
        super(myDialog, self).__init__(parent)
        self.keyPressed.connect(self.on_key)

        leftGroupBox = QtWidgets.QGroupBox('A Group Label')
        text = QtWidgets.QTextEdit('Enter some text')
        layout = QtWidgets.QVBoxLayout()
        layout.addWidget(text)
        leftGroupBox.setLayout(layout)

        rightGroupBox = QtWidgets.QGroupBox('Label Options')
        label1 = QtWidgets.QCheckBox('ahu')
        layout = QtWidgets.QVBoxLayout()
        layout.addWidget(label1)
        rightGroupBox.setLayout(layout)

        # Create the main layout
        mainLayout = QtWidgets.QGridLayout()
        mainLayout.addWidget(leftGroupBox)
        mainLayout.addWidget(rightGroupBox)
        self.setLayout(mainLayout)

    def keyPressEvent(self, event):
        # keyPressEvent defined in child
        print('pressed from myDialog: ', event.key())
#        self.keyPressed.emit(event) # Emit is hidden in child

    def on_key(self, event):
        print('event received @ myDialog')
        if event.key() == QtCore.Qt.Key_0:
            print(0)

class MainWindow(QtWidgets.QMainWindow):
    keyPressed = QtCore.pyqtSignal(QtCore.QEvent)

    def __init__(self):
        super(MainWindow, self).__init__()
        self.keyPressed.connect(self.on_key)
        self.setCentralWidget(myDialog())
        self.show()

    def keyPressEvent(self, event):
        super(MainWindow, self).keyPressEvent(event)
        print('pressed from MainWindow: ', event.key())
        self.keyPressed.emit(event)


    def on_key(self, event):
        print('event received @ MainWindow')
        if event.key() == QtCore.Qt.Key_0:
            print(0)

if __name__ == '__main__':
    ex = MainWindow()

Output @ console : (no event is received @myDialog OR MainWindow)
pressed from myDialog:  48