Ich habe mal das Beispiel erweitert. Nachfolgend werde ich euch das Beispiel vorstellen.
Mein
Problem ist, dass - sobald ich den
eventFilter() installiert habe - die Cursortasten, Löschen- und Entfern-Tasten nicht wirklich greifen. In diesem Beispiel möchte ich, dass der Benutzer nicht so oft mit der Leertaste rumspielt. Ich möchte also seine Leertaste
überwachen.
Problem-Hergang. Sobald das Beispiel-Programm gestartet wird,kann man mittels der Schaltflächen den
eventFilter() installieren, und wahlweise auch deinstallieren. Wenn der
eventFilter() nun installiert ist, und ich markiere den getippten Text im
QLineEdit()-Objekt und drücke anschließend die Lösch- und/oder Entfern-Taste, dann passiert
gar nichts. Der Inhalt des
QLineEdit()-Objektes wird nicht gelöscht. Muss ich jetzt hingehen und sämtliche Tasten nun händisch verwalten?
Code: Alles auswählen
#!/usr/bin/env python
import sys
from PyQt4.QtCore import QEvent, Qt
from PyQt4.QtGui import QMainWindow, QWidget, QApplication, QVBoxLayout, QLineEdit, QPushButton
class Window(QMainWindow):
def __init__(self, parent=None):
QMainWindow.__init__(self, parent)
self.count_space_pressed = 0
self.current_pos = None
self.init_ui()
self.init_signal_slot_push_button()
def init_ui(self):
centralwidget = QWidget(self)
self.input_line_edit = QLineEdit(self)
self.close_push = QPushButton(self)
self.close_push.setEnabled(False)
self.close_push.setText("Close")
self.push_install = QPushButton(self)
self.push_install.setText("Install eventFilter")
self.push_deinstall = QPushButton(self)
self.push_deinstall.setText("Deinstall eventFilter")
layout = QVBoxLayout(centralwidget)
layout.addWidget(self.input_line_edit)
layout.addWidget(self.push_install)
layout.addWidget(self.push_deinstall)
layout.addWidget(self.close_push)
self.setCentralWidget(centralwidget)
return
def install_filter_event(self, widget_object):
widget_object.installEventFilter(self)
return
def deinstall_filter_event(self, widget_object):
widget_object.removeEventFilter(self)
return
def init_signal_slot_push_button(self):
self.close_push.clicked.connect(self.close)
self.push_install.clicked.connect(lambda: self.install_filter_event(self.input_line_edit))
self.push_deinstall.clicked.connect(lambda: self.deinstall_filter_event(self.input_line_edit))
return
def strip_string(self, content, site=None):
if site == "right":
return content.rstrip()
elif site == "right_left":
return content.strip()
elif site == "left":
return content.lstrip()
def eventFilter(self, received_object, event):
content_line_edit = unicode(received_object.text())
if event.type() == QEvent.KeyPress:
if event.key() == Qt.Key_Space:
'''
Yes, the user did press the Space-Key. We
count how often he pressed the space key.
'''
self.count_space_pressed = self.count_space_pressed + 1
if int(self.count_space_pressed) > 1:
'''
The user did press the space key more than 1 time.
'''
self.close_push.setEnabled(False)
'''
Now we know the user did press the
space key more than 1 time. We take a look,
if variablenamed (sel.current_pos) is None.
That means, no current position is saved.
'''
if self.current_pos is None:
'''
Well no current position is saved,
that why we save the new position anf
then we set the position of the cursor.
'''
self.current_pos = received_object.cursorPosition()
received_object.setCursorPosition(int(self.current_pos))
received_object.clear()
received_object.setText(self.strip_string(content_line_edit, site="right"))
else:
'''
Well the user press the space key again, for
example 3, 4, 5, 6 times we want to keep the
old position of the cursor until he press
no space key.
'''
received_object.setCursorPosition(int(self.current_pos))
'''
We have to remove all spaces in a string
on the right side and set the content on QLineEdit-widget.
'''
received_object.clear()
received_object.setText(self.strip_string(content_line_edit, site="right"))
else: pass
else:
'''
No the user didn't press the space key.
So we set all setting on default.
'''
self.close_push.setEnabled(True)
self.current_pos = None
self.count_space_pressed = 0
received_object.clear()
received_object.setText(self.strip_string(content_line_edit, site="left"))
# Call Base Class Method to Continue Normal Event Processing
return QMainWindow.eventFilter(self, received_object, event)
if __name__ == '__main__':
app = QApplication(sys.argv)
window = Window()
window.show()
app.exec_()
