在pyqt中如何在按下Ctrl + anyKey时在QLineEdit中打印"Ctrl+key"

Question

在我的代码中，我为 QLineEdit 生成事件以将按下的组合键放在文本行中它可以用于 Shift 键和 Alt 键但不能用于 Ctrl 键为什么？

#!/usr/bin/python

import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *

def main():
    app = QApplication(sys.argv)
    w = MyWindow()
    w.show()
    sys.exit(app.exec_())
class MyWindow(QWidget):
    def __init__(self, *args):
        QWidget.__init__(self, *args)

        self.la = QLabel("Press tab in this box:")
        self.le = MyLineEdit()


        layout = QVBoxLayout()
        layout.addWidget(self.la)
        layout.addWidget(self.le)
        self.setLayout(layout)


        self.connect(self.le, SIGNAL("press"),
                 self.update)

    def update(self):
        oldText = str(self.le.text())
        self.le.setText(self.le.myText)

class MyLineEdit(QLineEdit):
    def __init__(self, *args):
        QLineEdit.__init__(self, *args)

        self.myText = ""
    def event(self, event):
        if event.type() == QEvent.KeyPress:
            if  event.modifiers() & Qt.ControlModifier  :

在文本行中可以使用 Shift 键和 Alt 键我可以在文本行中输入变量 self.myText 值，但不能用于 Ctrl 键，为什么？

                print event.text()
                self.myText = "Ctrl+"+ event.text()
                self.emit(SIGNAL("press"))
            return True
        return QLineEdit.event(self, event)

if __name__ == "__main__":
    main()

Answer 1

当我们使用 key() 方法是可能的，其中 return 键的 int 值，那么我们只需使用 unichr() 函数将 int 转换为 char

class MyLineEdit(QLineEdit):
    def __init__(self, *args):
        QLineEdit.__init__(self, *args)

    def event(self, event):
        self.myText = ""
        event_key = ""
        if event.type() == QEvent.KeyPress:
            if event.text() != "" :
                event_key = str(unichr(event.key())).lower()
            if event.modifiers()==  Qt.ControlModifier  :
                print event.text()
                self.myText = "Ctrl+" + event_key
            self.emit(SIGNAL("press"))
            return True
        return QLineEdit.event(self, event)

Answer 2

原始示例不起作用的原因是因为许多 Ctrl+key 组合会产生控制字符 - 例如Ctrl+J 产生一个换行符。

捕获键盘组合的正确方法是使用 QKeySequence, which will work for all keys, including function keys, arrow keys, page up/down keys, etc. You can also get translated shortcuts by using QKeySequence.PortableText。

这是一个基于原始示例的演示：

import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *

def main():
    app = QApplication(sys.argv)
    w = MyWindow()
    w.show()
    sys.exit(app.exec_())

class MyWindow(QWidget):
    def __init__(self, *args):
        QWidget.__init__(self, *args)

        self.la = QLabel("Press tab in this box:")
        self.le = MyLineEdit()

        layout = QVBoxLayout()
        layout.addWidget(self.la)
        layout.addWidget(self.le)
        self.setLayout(layout)

        self.le.keyPressed.connect(self.update)

    def update(self, text):
        self.le.setText(text)

MOD_MASK = (Qt.CTRL | Qt.ALT | Qt.SHIFT | Qt.META)

class MyLineEdit(QLineEdit):
    keyPressed = pyqtSignal(str)

    def keyPressEvent(self, event):
        keyname = ''
        key = event.key()
        modifiers = int(event.modifiers())
        if (modifiers and modifiers & MOD_MASK == modifiers and
            key > 0 and key != Qt.Key_Shift and key != Qt.Key_Alt and
            key != Qt.Key_Control and key != Qt.Key_Meta):

            keyname = QKeySequence(modifiers + key).toString()

            print('event.text(): %r' % event.text())
            print('event.key(): %d, %#x, %s' % (key, key, keyname))

        self.keyPressed.emit(keyname)

if __name__ == "__main__":
    main()

在pyqt中如何在按下Ctrl + anyKey时在QLineEdit中打印"Ctrl+key"

in pyqt how to print "Ctrl+key" in QLineEdit when pressed Ctrl + anyKey

pyqt4

python-2.7