按下按钮时调用函数 [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.我怎么能做到这一点?

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() 槽参数应该是可调用的或不是nonetype"的信号

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 信号可以有参数，这些参数将传递给它们所连接的插槽；一个例子是新值作为信号 changed 中的参数.因此，虽然您可以有一个带参数的槽，但您不能在将信号连接到槽时定义这些值的实际值，因为它们将在发出信号时定义.

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.

为了在连接时定义一个参数，你可以使用一个额外的函数，它只用定义的参数调用原始函数:

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)

附带说明:wrapper 在这里不使用大括号:该函数不被调用，只是作为参数传递给函数 connect.在你的代码中，你调用你的函数funcion，它什么都不返回(=None)，它被传递给connect> 在您的原始代码中，导致您收到错误消息.

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.

为了更简洁，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 也提供了执行此操作的方法，但(至少对我而言)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.

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

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