按下按钮时调用功能 [英] Calling a function upon button press

问题描述

当我单击 btn_brow_3 时，我试图调用函数 funcion 。我该怎么办呢？

I am trying to call function funcion when I click btn_brow_3. How could I accomplish this?

运行以下代码时，我收到此错误消息：
TypeError：connect（）slot参数应该是可调用的或信号不是无类型

When running the following code, I receive this error message: TypeError: connect() slot argument should be a callable or a signal not "nonetype"

import atexit
import sys
from PyQt4 import QtGui
import os                           # Libreria para manejar directorios del sistema operativo

def funcion(a):
    print "Hola mundo" + str(a)

class Example(QtGui.QMainWindow):

    def __init__(self):
        super(Example, self).__init__()
        
        self.initUI()
        
    def initUI(self):               
        
        exitAction = QtGui.QAction(QtGui.QIcon('c:/prueba gui/resource/logo.png'), 'Exit', self)
        exitAction.setShortcut('Ctrl+Q')
        exitAction.triggered.connect(QtGui.qApp.quit)
        
        btn_brow_1 = QtGui.QPushButton('Browser...', self)
        btn_brow_1.resize(btn_brow_1.sizeHint())
        btn_brow_1.move(300, 50)
        btn_brow_1.clicked.connect(self.showDialog_points)
        
        btn_brow_2 = QtGui.QPushButton('Dir browser', self)
        btn_brow_2.resize(btn_brow_2.sizeHint())
        btn_brow_2.move(300, 80)
        btn_brow_2.clicked.connect(self.showDialog_indir_stl)
        
        btn_brow_3 = QtGui.QPushButton('Dir browser', self)
        btn_brow_3.resize(btn_brow_3.sizeHint())
        btn_brow_3.move(300, 110)
        btn_brow_3.clicked.connect(self.showDialog_outdir_stl)
        
        
        
        
        btn_brow_4 = QtGui.QPushButton('Crear soportes', self)
        btn_brow_4.setGeometry(20, 145, 250, 25)
        #btn_brow_4.clicked.connect(support.main(fname_points, self.fname_stl_indir, self.fname_stl_outdir))
        btn_brow_4.clicked.connect(funcion(12))  # HERE IS THE PROBLEM!
        
        self.le1 = QtGui.QLineEdit(self)
        self.le1.setGeometry(20, 50, 250,21)
        
        self.le2 = QtGui.QLineEdit(self)
        self.le2.setGeometry(20, 80, 250,21)
        
        self.le3 = QtGui.QLineEdit(self)
        self.le3.setGeometry(20, 110, 250,21)
        
        self.statusBar().showMessage("Ready")
        
        self.toolbar = self.addToolBar('Exit')
        self.toolbar.addAction(exitAction)
        
        self.setGeometry(300, 300, 400, 200)
        self.setWindowTitle('Support from points generator')    
        self.show()
        
        
    
    def showDialog_points(self):
        
        self.fname_points = QtGui.QFileDialog.getOpenFileName(self, 'Open points file', '/home')
        self.statusBar().showMessage(str(self.fname_points))
        self.le1.setText(str(self.fname_points))
        self.fname_points = str(self.le1.text())
        print fname_points

    
    def showDialog_indir_stl(self):
        
        self.fname_stl_indir = QtGui.QFileDialog.getExistingDirectory(self, 'Select STL INPUT directory', '/home')
        self.statusBar().showMessage(str(self.fname_stl_indir))
        self.le2.setText(str(self.fname_stl_indir))
        self.fname_stl_indir = str(self.le2.text())
        print fname_stl_indir 

    def showDialog_outdir_stl(self):
        
        self.fname_stl_outdir = QtGui.QFileDialog.getExistingDirectory(self, 'Select STL OUTPUT directory', '/home')
        self.statusBar().showMessage(str(self.fname_stl_outdir))
        self.le3.setText(str(self.fname_stl_outdir))
        self.fname_stl_outdir = str(self.le3.text())
        print fname_stl_outdir 
  
def main():
    
    app = QtGui.QApplication(sys.argv)
    ex = Example()
    
    
    sys.exit(app.exec_())
    
if __name__ == '__main__':
    main()

推荐答案

Qt信号可以具有传递给它们所连接的插槽的参数；例如，将新值作为信号 changed 中的自变量。因此，尽管可以有一个带有参数的插槽，但是您无法定义将信号连接到插槽时的实际值，因为在发出信号时将定义它们的实际值。

Qt signals can have arguments that will be passed to the slots they are connected to; an example would be the new value as an argument in a signal changed. Therefore, while you can have a slot with arguments, you cannot define the actual values of those when connecting the signal to the slot, as they will be defined when emitting signal.

要在连接时定义参数，可以使用一个附加函数，除了使用定义的参数调用原始函数外，该函数什么也没做：

For defining an argument at connect time, you can use an additional function which does nothing but calling the original function with the defined argument:

def wrapper():
    funcion(12)

def funcion(a):
    print "Hola mundo" + str(a)

[...]
btn_brow_4.clicked.connect(wrapper)

作为旁注： wrapper 在此处不使用花括号：该函数不会被调用，而只是作为参数传递给函数 connect 。在您的代码中，您调用了函数 funcion ，该函数不返回任何内容（= None ） ，它已在原始代码中传递给 connect ，从而导致收到错误消息。

As a side note: wrapper does not use braces here: the function is not called, but simply passed as an argument to the function connect. In your code, you called your function funcion, which returns nothing (=None), which was passed to connect in your original code, resulting in the error message you received.

为此更加简洁一些，您还可以使用匿名函数：

To make that a bit cleaner, you can also use an anonymous function:

btn_brow_4.clicked.connect(lambda: funcion(12))

请注意，Qt也提供了这样做的方法，但是（至少对于我）Python变体更易于阅读。

Note that Qt also provides ways of doing this, but (at least for me) the Python variants are easier to read.

编辑：更多信息：> http://eli.thegreenplace.net/2011/04/25/passing-extra-arguments- to-pyqt-slot /

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