如何在PyQt中检测按键释放

Question

我想创建一个PyQt5窗口（Windows操作系统），该窗口可以识别按住CTRL按钮的按钮点击。我成功地创建了一个处理程序，它可以识别CTRL键的按下，但它无法找到所需的按钮按下和释放来调用和解除按钮点击事件。我进行了大量搜索，但是关于PyQt5的资源似乎非常有限。任何帮助都将不胜感激 :)

"最初的回答"：抱歉，我不能为您提供代码，但我可以向您建议使用QShortcut类，该类允许在没有焦点的情况下捕获按键事件，并且可以与按钮单击事件一起使用。

import time
from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_Dialog(QtWidgets.QWidget):
    def __init__(self):
        QtWidgets.QWidget.__init__(self)
        self.setupUi(self)
        self.show()
        self.signals()
        self.bleahOK=True

    def setupUi(self, Dialog):
        Dialog.setObjectName("Dialog")
        Dialog.resize(392, 255)
        self.unlockButton = QtWidgets.QPushButton(Dialog)
        self.unlockButton.setGeometry(QtCore.QRect(10, 180, 171, 51))
        self.unlockButton.setObjectName("unlockButton")
        self.lockButton = QtWidgets.QPushButton(Dialog)
        self.lockButton.setGeometry(QtCore.QRect(220, 180, 151, 51))
        self.lockButton.setObjectName("lockButton")
        self.label = QtWidgets.QLabel(Dialog)
        self.label.setGeometry(QtCore.QRect(30, 30, 331, 71))
        font = QtGui.QFont()
        font.setPointSize(12)
        self.label.setFont(font)
        self.label.setObjectName("label")
        self.lineEdit = QtWidgets.QLineEdit(Dialog)
        self.lineEdit.setGeometry(QtCore.QRect(30, 120, 261, 31))
        font = QtGui.QFont()
        font.setPointSize(18)
        self.lineEdit.setFont(font)
        self.lineEdit.setObjectName("lineEdit")

        self.retranslateUi(Dialog)
        QtCore.QMetaObject.connectSlotsByName(Dialog)

    def retranslateUi(self, Dialog):
        _translate = QtCore.QCoreApplication.translate
        Dialog.setWindowTitle(_translate("Dialog", "Dialog"))
        self.unlockButton.setText(_translate("Dialog", "OK"))
        self.lockButton.setText(_translate("Dialog", "Lock"))
        self.label.setText(_translate("Dialog", ""))
        self.lineEdit.setText(_translate("Dialog", ""))

    def signals(self):
        self.unlockButton.clicked.connect(self.unlock)

    def unlock(self):
        if 1: print('ff')            

    def keyPressEvent(self, event):
         if type(event) == QtGui.QKeyEvent: #Unable to find when the key was released
            print (event.key())          
            event.accept()
         else:
             event.ignore()     

    def lock(self):
        print("Test")

if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    Dialog = QtWidgets.QDialog()
    ui = Ui_Dialog()
    ui.setupUi(Dialog)
    # ui.signals()
    # Dialog.show()
    sys.exit(app.exec_())

- Siva Manasan

---

一些反馈？ - eyllanesc

@eyllanesc 不要直接创建一个小部件，而是创建一个继承适当小部件的类，并将该类用作接口。 您能给我展示一个示例，如何从另一个继承主UI的py文件打开gui.py以控制用户操作？ - Siva Manasan

嗯，我不明白你的意思，我的解决方案对你有用吗？如果你有其他问题，请另发帖子 :-) - eyllanesc

如何使用正确的语法从另一个py文件继承GUI类？你能给我展示一个例子吗？ - Siva Manasan

我需要在那个类中放置def ___init___吗？ - Siva Manasan

是的，这是典型的继承。请查看：https://dev59.com/O2w15IYBdhLWcg3w0fAV - eyllanesc

Answer 1

我建议您不要修改Qt Designer生成的代码，而是创建一个继承适当小部件的类，并将该类用作接口，就像我推荐PyQt一样。 解决问题时，您必须使用keyReleaseEvent方法来监听何时释放键：

import time
from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_Dialog(object):
    def setupUi(self, Dialog):
        Dialog.setObjectName("Dialog")
        Dialog.resize(392, 255)
        self.unlockButton = QtWidgets.QPushButton(Dialog)
        self.unlockButton.setGeometry(QtCore.QRect(10, 180, 171, 51))
        self.unlockButton.setObjectName("unlockButton")
        self.lockButton = QtWidgets.QPushButton(Dialog)
        self.lockButton.setGeometry(QtCore.QRect(220, 180, 151, 51))
        self.lockButton.setObjectName("lockButton")
        self.label = QtWidgets.QLabel(Dialog)
        self.label.setGeometry(QtCore.QRect(30, 30, 331, 71))
        font = QtGui.QFont()
        font.setPointSize(12)
        self.label.setFont(font)
        self.label.setObjectName("label")
        self.lineEdit = QtWidgets.QLineEdit(Dialog)
        self.lineEdit.setGeometry(QtCore.QRect(30, 120, 261, 31))
        font = QtGui.QFont()
        font.setPointSize(18)
        self.lineEdit.setFont(font)
        self.lineEdit.setObjectName("lineEdit")

        self.retranslateUi(Dialog)
        QtCore.QMetaObject.connectSlotsByName(Dialog)

    def retranslateUi(self, Dialog):
        _translate = QtCore.QCoreApplication.translate
        Dialog.setWindowTitle(_translate("Dialog", "Dialog"))
        self.unlockButton.setText(_translate("Dialog", "OK"))
        self.lockButton.setText(_translate("Dialog", "Lock"))
        self.label.setText(_translate("Dialog", ""))
        self.lineEdit.setText(_translate("Dialog", ""))

class Dialog(QtWidgets.QDialog, Ui_Dialog):
    def __init__(self, parent=None):
        super(Dialog, self).__init__(parent)
        self.setupUi(self)
        self.is_key_ctrl_pressed = False
        self.unlockButton.clicked.connect(self.unlock)

    @QtCore.pyqtSlot()
    def unlock(self):
        if self.is_key_ctrl_pressed:
            print("unlock")

    def keyPressEvent(self, event):
        if event.key() == QtCore.Qt.Key_Control:
            self.is_key_ctrl_pressed = True
        super(Dialog, self).keyPressEvent(event)

    def keyReleaseEvent(self, event):
        if event.key() == QtCore.Qt.Key_Control:
            self.is_key_ctrl_pressed = False
        super(Dialog, self).keyReleaseEvent(event)

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

- eyllanesc