ComboBox 函数 currentIndexChanged 无法正常工作
ComboBox function currentIndexChanged not working correctly
我使用了两个组合框，即 comboBox1 和 comboBox_2 以及两个函数 test 和 test1，并使用 currentIndexChanged（self.comboBOx1.currentIndexChanged 和 self.comboBOx_2.currentIndexChanged）调用它们。当一个值从 comboBox1 中被 selected 时，其对应的函数 (self.comboBOx1.currentIndexChanged) 被调用，comboBox_2 也是如此。在 select ion of value from comboBox1 更改 comboBox_2 中的值及其工作正常。但我在这里遇到的问题是，起初当我 select 来自 comboBox1 和 comboBox_2 的值时，我从被调用的函数（打印 'hello'）中获取预期值。第二次，当我 select 来自 comboBox1 的值时，只应调用测试函数，但这里两个函数（测试和测试 1）都被调用，第二个函数（测试 1）被调用两次（打印 'hello' 两次），第三次被调用四次（打印 'hello' 四次）。请问有人能帮我解决这个问题吗？
代码：
from PyQt4 import QtCore, QtGui
try:
_fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
def _fromUtf8(s):
return s
try:
_encoding = QtGui.QApplication.UnicodeUTF8
def _translate(context, text, disambig):
return QtGui.QApplication.translate(context, text, disambig, _encoding)
except AttributeError:
def _translate(context, text, disambig):
return QtGui.QApplication.translate(context, text, disambig)
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName(_fromUtf8("MainWindow"))
MainWindow.resize(800, 600)
self.centralwidget = QtGui.QWidget(MainWindow)
self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
self.comboBox1 = QtGui.QComboBox(self.centralwidget)
self.comboBox1.setGeometry(QtCore.QRect(310, 150, 171, 31))
self.comboBox1.setObjectName(_fromUtf8("comboBox1"))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox_2 = QtGui.QComboBox(self.centralwidget)
self.comboBox_2.setGeometry(QtCore.QRect(310, 240, 171, 41))
self.comboBox_2.setObjectName(_fromUtf8("comboBox_2"))
self.comboBox_2.addItem(_fromUtf8(""))
self.comboBox_2.addItem(_fromUtf8(""))
self.comboBox_2.addItem(_fromUtf8(""))
self.comboBox_2.addItem(_fromUtf8(""))
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtGui.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 21))
self.menubar.setObjectName(_fromUtf8("menubar"))
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtGui.QStatusBar(MainWindow)
self.statusbar.setObjectName(_fromUtf8("statusbar"))
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow", None))
self.comboBox1.setItemText(0, _translate("MainWindow", "select", None))
self.comboBox1.setItemText(1, _translate("MainWindow", "a", None))
self.comboBox1.setItemText(2, _translate("MainWindow", "b", None))
self.comboBox1.setItemText(3, _translate("MainWindow", "c", None))
self.comboBox_2.setItemText(0, _translate("MainWindow", "select", None))
self.comboBox_2.setItemText(1, _translate("MainWindow", "p", None))
self.comboBox_2.setItemText(2, _translate("MainWindow", "q", None))
self.comboBox_2.setItemText(3, _translate("MainWindow", "r", None))
self.comboBox_2.setEnabled(0)
self.comboBox1.currentIndexChanged.connect(self.test)
def test(self):
s = str(self.comboBox1.currentText())
res=['aa','bb','cc','dd']
if (s == "- - select - -"):
self.comboBox_2.setEnabled(0)
self.comboBox_2.setCurrentIndex(0)
elif(len(s)== 0):
self.comboBox_2.setEnabled(1)
self.comboBox_2.clear()
self.comboBox_2.addItem("- - select - -")
self.comboBox_2.addItem("New Checklist")
else:
self.comboBox_2.setEnabled(1)
self.comboBox_2.clear()
self.comboBox_2.addItem("- - select - -")
self.comboBox_2.addItem("New Checklist")
self.comboBox_2.addItems(res)
self.comboBox_2.currentIndexChanged.connect(self.test1)
def test1(self):
print ("Hello")
if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
MainWindow = QtGui.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())
为了理解我们将使用以下示例的行为：
示例 1:
from PyQt4 import QtCore, QtGui
def on_clicked():
print("clicked")
if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
button = QtGui.QPushButton("Press me")
for _ in range(4):
button.clicked.connect(on_clicked)
button.show()
sys.exit(app.exec_())
当你按下按钮时，它会打印 4 次，因为 Qt 不记得之前信号和函数之间是否已经存在连接，所以如果同一个信号和函数之间有 n 个连接，它们将被调用 n 次当信号发出时。
示例 2:
from PyQt4 import QtCore, QtGui
def on_currentIndexChanged(ix):
print("currentIndex:", ix)
if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
combo = QtGui.QComboBox()
print("currentIndex:", combo.currentIndex())
combo.currentIndexChanged.connect(on_currentIndexChanged)
button_add = QtGui.QPushButton("Add Items")
button_add.clicked.connect(lambda: combo.addItems("1 2 3".split()))
button_clear = QtGui.QPushButton("Clear")
button_clear.clicked.connect(combo.clear)
w = QtGui.QWidget()
lay = QtGui.QVBoxLayout(w)
for widget in (combo, button_add, button_clear):
lay.addWidget(widget)
w.show()
sys.exit(app.exec_())
QComboBox 的默认 currentIndex 为 -1，当您添加项目时，这会更改为 0 的 currentIndex，而当您清理 QComboBox 时，currentIndex 会恢复为 -1。因此，当您添加或清理项目时，会发出 currentIndexChanged 信号。
基于以上，我将解释您指出的行为：当在 QCombobox 1 中选择一个新的 currentIndex 时，将调用测试方法，如果它进入 else 清理并添加您建立第一个连接的项目后的语句，如果现在因为有连接而重复相同的事情，则 currentIndexChanged 信号会发出两次（一次用于 clear() ，另一个用于 addItems() ）并且您还创建第二个连接，如果再次重复，信号会发出 4 次（1 clear() x 2 connections + 1 addItems() x 2 connections）。
解法：
- 在仅调用一次的函数中建立连接。
- 为了使 clear() 信号和 addItems() 不发出 currentIndexChanged 信号，您必须使用 blockSignals()。
- 作为附加点，建议不要修改 Qt Designer 生成的代码，建议创建另一个使用初始 class 作为接口的 class，除了使用装饰@QtCore.pyqtSlot().
from PyQt4 import QtCore, QtGui
try:
_fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
def _fromUtf8(s):
return s
try:
_encoding = QtGui.QApplication.UnicodeUTF8
def _translate(context, text, disambig):
return QtGui.QApplication.translate(context, text, disambig, _encoding)
except AttributeError:
def _translate(context, text, disambig):
return QtGui.QApplication.translate(context, text, disambig)
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName(_fromUtf8("MainWindow"))
MainWindow.resize(800, 600)
self.centralwidget = QtGui.QWidget(MainWindow)
self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
self.comboBox1 = QtGui.QComboBox(self.centralwidget)
self.comboBox1.setGeometry(QtCore.QRect(310, 150, 171, 31))
self.comboBox1.setObjectName(_fromUtf8("comboBox1"))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox_2 = QtGui.QComboBox(self.centralwidget)
self.comboBox_2.setGeometry(QtCore.QRect(310, 240, 171, 41))
self.comboBox_2.setObjectName(_fromUtf8("comboBox_2"))
self.comboBox_2.addItem(_fromUtf8(""))
self.comboBox_2.addItem(_fromUtf8(""))
self.comboBox_2.addItem(_fromUtf8(""))
self.comboBox_2.addItem(_fromUtf8(""))
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtGui.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 21))
self.menubar.setObjectName(_fromUtf8("menubar"))
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtGui.QStatusBar(MainWindow)
self.statusbar.setObjectName(_fromUtf8("statusbar"))
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow", None))
self.comboBox1.setItemText(0, _translate("MainWindow", "select", None))
self.comboBox1.setItemText(1, _translate("MainWindow", "a", None))
self.comboBox1.setItemText(2, _translate("MainWindow", "b", None))
self.comboBox1.setItemText(3, _translate("MainWindow", "c", None))
self.comboBox_2.setItemText(0, _translate("MainWindow", "select", None))
self.comboBox_2.setItemText(1, _translate("MainWindow", "p", None))
self.comboBox_2.setItemText(2, _translate("MainWindow", "q", None))
self.comboBox_2.setItemText(3, _translate("MainWindow", "r", None))
class MainWindow(QtGui.QMainWindow, Ui_MainWindow):
def __init__(self, parent=None):
super(MainWindow, self).__init__(parent)
self.setupUi(self)
self.comboBox_2.setEnabled(False)
self.comboBox1.currentIndexChanged[str].connect(self.test)
self.comboBox_2.currentIndexChanged.connect(self.test1)
@QtCore.pyqtSlot(str)
def test(self, s):
res=['aa','bb','cc','dd']
if s == "- - select - -":
self.comboBox_2.setEnabled(False)
self.comboBox_2.setCurrentIndex(0)
elif not s:
self.comboBox_2.setEnabled(True)
self.comboBox_2.blockSignals(True)
self.comboBox_2.clear()
self.comboBox_2.addItem("- - select - -")
self.comboBox_2.addItem("New Checklist")
self.comboBox_2.blockSignals(False)
else:
self.comboBox_2.setEnabled(True)
self.comboBox_2.blockSignals(True)
self.comboBox_2.clear()
self.comboBox_2.addItem("- - select - -")
self.comboBox_2.addItem("New Checklist")
self.comboBox_2.addItems(res)
self.comboBox_2.blockSignals(False)
@QtCore.pyqtSlot(int)
def test1(self, ix):
print("Hello", ix)
if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())
我使用了两个组合框，即 comboBox1 和 comboBox_2 以及两个函数 test 和 test1，并使用 currentIndexChanged（self.comboBOx1.currentIndexChanged 和 self.comboBOx_2.currentIndexChanged）调用它们。当一个值从 comboBox1 中被 selected 时，其对应的函数 (self.comboBOx1.currentIndexChanged) 被调用，comboBox_2 也是如此。在 select ion of value from comboBox1 更改 comboBox_2 中的值及其工作正常。但我在这里遇到的问题是，起初当我 select 来自 comboBox1 和 comboBox_2 的值时，我从被调用的函数（打印 'hello'）中获取预期值。第二次，当我 select 来自 comboBox1 的值时，只应调用测试函数，但这里两个函数（测试和测试 1）都被调用，第二个函数（测试 1）被调用两次（打印 'hello' 两次），第三次被调用四次（打印 'hello' 四次）。请问有人能帮我解决这个问题吗？
代码：
from PyQt4 import QtCore, QtGui
try:
_fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
def _fromUtf8(s):
return s
try:
_encoding = QtGui.QApplication.UnicodeUTF8
def _translate(context, text, disambig):
return QtGui.QApplication.translate(context, text, disambig, _encoding)
except AttributeError:
def _translate(context, text, disambig):
return QtGui.QApplication.translate(context, text, disambig)
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName(_fromUtf8("MainWindow"))
MainWindow.resize(800, 600)
self.centralwidget = QtGui.QWidget(MainWindow)
self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
self.comboBox1 = QtGui.QComboBox(self.centralwidget)
self.comboBox1.setGeometry(QtCore.QRect(310, 150, 171, 31))
self.comboBox1.setObjectName(_fromUtf8("comboBox1"))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox_2 = QtGui.QComboBox(self.centralwidget)
self.comboBox_2.setGeometry(QtCore.QRect(310, 240, 171, 41))
self.comboBox_2.setObjectName(_fromUtf8("comboBox_2"))
self.comboBox_2.addItem(_fromUtf8(""))
self.comboBox_2.addItem(_fromUtf8(""))
self.comboBox_2.addItem(_fromUtf8(""))
self.comboBox_2.addItem(_fromUtf8(""))
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtGui.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 21))
self.menubar.setObjectName(_fromUtf8("menubar"))
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtGui.QStatusBar(MainWindow)
self.statusbar.setObjectName(_fromUtf8("statusbar"))
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow", None))
self.comboBox1.setItemText(0, _translate("MainWindow", "select", None))
self.comboBox1.setItemText(1, _translate("MainWindow", "a", None))
self.comboBox1.setItemText(2, _translate("MainWindow", "b", None))
self.comboBox1.setItemText(3, _translate("MainWindow", "c", None))
self.comboBox_2.setItemText(0, _translate("MainWindow", "select", None))
self.comboBox_2.setItemText(1, _translate("MainWindow", "p", None))
self.comboBox_2.setItemText(2, _translate("MainWindow", "q", None))
self.comboBox_2.setItemText(3, _translate("MainWindow", "r", None))
self.comboBox_2.setEnabled(0)
self.comboBox1.currentIndexChanged.connect(self.test)
def test(self):
s = str(self.comboBox1.currentText())
res=['aa','bb','cc','dd']
if (s == "- - select - -"):
self.comboBox_2.setEnabled(0)
self.comboBox_2.setCurrentIndex(0)
elif(len(s)== 0):
self.comboBox_2.setEnabled(1)
self.comboBox_2.clear()
self.comboBox_2.addItem("- - select - -")
self.comboBox_2.addItem("New Checklist")
else:
self.comboBox_2.setEnabled(1)
self.comboBox_2.clear()
self.comboBox_2.addItem("- - select - -")
self.comboBox_2.addItem("New Checklist")
self.comboBox_2.addItems(res)
self.comboBox_2.currentIndexChanged.connect(self.test1)
def test1(self):
print ("Hello")
if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
MainWindow = QtGui.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())
为了理解我们将使用以下示例的行为：
示例 1:
from PyQt4 import QtCore, QtGui
def on_clicked():
print("clicked")
if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
button = QtGui.QPushButton("Press me")
for _ in range(4):
button.clicked.connect(on_clicked)
button.show()
sys.exit(app.exec_())
当你按下按钮时，它会打印 4 次，因为 Qt 不记得之前信号和函数之间是否已经存在连接，所以如果同一个信号和函数之间有 n 个连接，它们将被调用 n 次当信号发出时。
示例 2:
from PyQt4 import QtCore, QtGui
def on_currentIndexChanged(ix):
print("currentIndex:", ix)
if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
combo = QtGui.QComboBox()
print("currentIndex:", combo.currentIndex())
combo.currentIndexChanged.connect(on_currentIndexChanged)
button_add = QtGui.QPushButton("Add Items")
button_add.clicked.connect(lambda: combo.addItems("1 2 3".split()))
button_clear = QtGui.QPushButton("Clear")
button_clear.clicked.connect(combo.clear)
w = QtGui.QWidget()
lay = QtGui.QVBoxLayout(w)
for widget in (combo, button_add, button_clear):
lay.addWidget(widget)
w.show()
sys.exit(app.exec_())
QComboBox 的默认 currentIndex 为 -1，当您添加项目时，这会更改为 0 的 currentIndex，而当您清理 QComboBox 时，currentIndex 会恢复为 -1。因此，当您添加或清理项目时，会发出 currentIndexChanged 信号。
基于以上，我将解释您指出的行为：当在 QCombobox 1 中选择一个新的 currentIndex 时，将调用测试方法，如果它进入 else 清理并添加您建立第一个连接的项目后的语句，如果现在因为有连接而重复相同的事情，则 currentIndexChanged 信号会发出两次（一次用于 clear() ，另一个用于 addItems() ）并且您还创建第二个连接，如果再次重复，信号会发出 4 次（1 clear() x 2 connections + 1 addItems() x 2 connections）。
解法：
- 在仅调用一次的函数中建立连接。
- 为了使 clear() 信号和 addItems() 不发出 currentIndexChanged 信号，您必须使用 blockSignals()。
- 作为附加点，建议不要修改 Qt Designer 生成的代码，建议创建另一个使用初始 class 作为接口的 class，除了使用装饰@QtCore.pyqtSlot().
from PyQt4 import QtCore, QtGui
try:
_fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
def _fromUtf8(s):
return s
try:
_encoding = QtGui.QApplication.UnicodeUTF8
def _translate(context, text, disambig):
return QtGui.QApplication.translate(context, text, disambig, _encoding)
except AttributeError:
def _translate(context, text, disambig):
return QtGui.QApplication.translate(context, text, disambig)
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName(_fromUtf8("MainWindow"))
MainWindow.resize(800, 600)
self.centralwidget = QtGui.QWidget(MainWindow)
self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
self.comboBox1 = QtGui.QComboBox(self.centralwidget)
self.comboBox1.setGeometry(QtCore.QRect(310, 150, 171, 31))
self.comboBox1.setObjectName(_fromUtf8("comboBox1"))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox1.addItem(_fromUtf8(""))
self.comboBox_2 = QtGui.QComboBox(self.centralwidget)
self.comboBox_2.setGeometry(QtCore.QRect(310, 240, 171, 41))
self.comboBox_2.setObjectName(_fromUtf8("comboBox_2"))
self.comboBox_2.addItem(_fromUtf8(""))
self.comboBox_2.addItem(_fromUtf8(""))
self.comboBox_2.addItem(_fromUtf8(""))
self.comboBox_2.addItem(_fromUtf8(""))
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtGui.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 21))
self.menubar.setObjectName(_fromUtf8("menubar"))
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtGui.QStatusBar(MainWindow)
self.statusbar.setObjectName(_fromUtf8("statusbar"))
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow", None))
self.comboBox1.setItemText(0, _translate("MainWindow", "select", None))
self.comboBox1.setItemText(1, _translate("MainWindow", "a", None))
self.comboBox1.setItemText(2, _translate("MainWindow", "b", None))
self.comboBox1.setItemText(3, _translate("MainWindow", "c", None))
self.comboBox_2.setItemText(0, _translate("MainWindow", "select", None))
self.comboBox_2.setItemText(1, _translate("MainWindow", "p", None))
self.comboBox_2.setItemText(2, _translate("MainWindow", "q", None))
self.comboBox_2.setItemText(3, _translate("MainWindow", "r", None))
class MainWindow(QtGui.QMainWindow, Ui_MainWindow):
def __init__(self, parent=None):
super(MainWindow, self).__init__(parent)
self.setupUi(self)
self.comboBox_2.setEnabled(False)
self.comboBox1.currentIndexChanged[str].connect(self.test)
self.comboBox_2.currentIndexChanged.connect(self.test1)
@QtCore.pyqtSlot(str)
def test(self, s):
res=['aa','bb','cc','dd']
if s == "- - select - -":
self.comboBox_2.setEnabled(False)
self.comboBox_2.setCurrentIndex(0)
elif not s:
self.comboBox_2.setEnabled(True)
self.comboBox_2.blockSignals(True)
self.comboBox_2.clear()
self.comboBox_2.addItem("- - select - -")
self.comboBox_2.addItem("New Checklist")
self.comboBox_2.blockSignals(False)
else:
self.comboBox_2.setEnabled(True)
self.comboBox_2.blockSignals(True)
self.comboBox_2.clear()
self.comboBox_2.addItem("- - select - -")
self.comboBox_2.addItem("New Checklist")
self.comboBox_2.addItems(res)
self.comboBox_2.blockSignals(False)
@QtCore.pyqtSlot(int)
def test1(self, ix):
print("Hello", ix)
if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())