PyQt4 error: unexpected type 'method'

Question

I'm trying to run a simple PyQT4 application. I've installed Python3.4 and PyQt4. I've tested a simple "Hello World" app and all works well. However when trying to code a simple tax calculator app I'm getting stuck with a "unexpected type 'method'" error. Not sure what I'm doing wrong. Here's my python code:

import sys
from PyQt4 import QtCore, QtGui, uic

qtCreatorFile = 'tax.ui' # Enter file here.

Ui_MainWindow, QtBaseClass = uic.loadUiType(qtCreatorFile)

class MyApp(QtGui.QMainWindow, Ui_MainWindow):
    def __init__(self):
        QtGui.QMainWindow.__init__(self)
        Ui_MainWindow.__init__(self)
        self.setupUi(self)
        self.calcTax.connect(self.CalculateTax)

    def CalculateTax(self):
        price = int(self.priceBox.toPlainText())
        tax = (self.taxRate.value())
        total_price = price  + ((tax / 100) * price)
        total_price_string = 'The total price with tax is: ' + str(total_price)
        self.resultBox.setText(total_price_string)

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    window = MyApp()
    window.show()
    sys.exit(app.exec_())

and here's the full error message returned when executing:

Traceback (most recent call last):
  File "tax.py", line 24, in <module>
    window = tax()
  File "tax.py", line 13, in __init__
    self.calcTax.connect(self.CalculateTax)
TypeError: arguments did not match any overloaded call:
  QObject.connect(QObject, SIGNAL(), QObject, SLOT(), Qt.ConnectionType=Qt.AutoConnection): argument 1 has unexpected type 'method'
  QObject.connect(QObject, SIGNAL(), callable, Qt.ConnectionType=Qt.AutoConnection): argument 1 has unexpected type 'method'
  QObject.connect(QObject, SIGNAL(), SLOT(), Qt.ConnectionType=Qt.AutoConnection): argument 1 has unexpected type 'method'

Would really appreciate any help

Answer 1

new connection style具有以下语法：

self.calcTax.some_signal.connect(self.CalculateTax)

例如，如果self.calcTax是一个按钮，并且您想在按下该按钮时执行该功能，则应该输入以下内容：

self.calcTax.clicked.connect(self.CalculateTax)