How to use QtGui in PyQt4 to collect input variables to a python program?

Question

Instead of input flags on the command line, using sys.argv, I want to change my python program so that a GUI with dialog boxes lets users provide answers to some questions. After the "apply" button is pushed I want the dialog GUI to dissapear and then the code to run normally with the variables provided in dialog boxes. I have tried many different ways using QtGui. Either it crashes, or, the answers are not known for the main program. Below I show one of my many attempts. In this example the answer is not known after the apply button is pressed. The output is

after widget answer1 = <blank no matter what I write in the dialog box>

I would very much appreciate help on how to change this code so that the variable "a1" is filled with the string given in the dialog box. Thank you!

import sys
from PyQt4 import QtGui

class Widget(QtGui.QWidget):

    def __init__(self):
        super(Widget, self).__init__()

        self.answer1 = QtGui.QLabel()
        q1Edit = QtGui.QLineEdit()
        q1Edit.textChanged[str].connect(self.q1Changed)

        grid = QtGui.QGridLayout()
        grid.setSpacing(20)

        grid.addWidget(QtGui.QLabel('Question 1'), 1, 0)
        grid.addWidget(q1Edit, 1, 1)
        grid.addWidget(self.answer1, 1, 2)

        applyBtn = QtGui.QPushButton('Apply', self)
        applyBtn.clicked.connect(self.close)

        self.answer1Text = self.answer1.text()

        grid.addWidget(applyBtn,4,3)

        self.setLayout(grid)     

        self.setGeometry(300, 300, 350, 300)
        self.show()


    def q1Changed(self, text):
        self.answer1.setText(text)

    def returnAnswer1(self):
        return self.answer1Text


def main():    
    app = QtGui.QApplication(sys.argv)
    w = Widget() 
    a1 = w.returnAnswer1()
    print("after widget answer1 = " + a1)    
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

Thanks to JRazor, this was in the end the solution:

import sys
from PyQt4 import QtGui

class Widget(QtGui.QDialog):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent)

        self.answer1 = QtGui.QLabel()
        q1Edit = QtGui.QLineEdit()
        q1Edit.textChanged.connect(self.q1Changed)

        self.answer2 = QtGui.QLabel()
        q2Edit = QtGui.QLineEdit()
        q2Edit.textChanged.connect(self.q2Changed)

        grid = QtGui.QGridLayout()
        grid.setSpacing(20)

        grid.addWidget(QtGui.QLabel('Question 1'), 1, 0)
        grid.addWidget(q1Edit, 1, 1)

        grid.addWidget(QtGui.QLabel('Question 2'), 2, 0)
        grid.addWidget(q2Edit, 2, 1)

        applyBtn = QtGui.QPushButton('Apply', self)
        applyBtn.clicked.connect(self.close)

        grid.addWidget(applyBtn,3,2)
        self.setLayout(grid)
        self.setGeometry(300, 300, 350, 300)

    def q1Changed(self, text):
        self.answer1.setText(text)

    def q2Changed(self, text):
        self.answer2.setText(text)

    def returnAnswer1(self):
        return self.answer1.text()

    def returnAnswer2(self):
        return self.answer2.text()

    @staticmethod
    def getData(parent=None):
        dialog = Widget(parent)
        dialog.exec_()
        return [dialog.returnAnswer1(), dialog.returnAnswer2()]

def main():
    app = QtGui.QApplication([])
    window = Widget()
    data = window.getData()
    print data[0]
    print data[1]


if __name__ == '__main__':
    main()

JRazor · Accepted Answer · 2016-04-17T15:46:49.703

0

You need change QWidget to QDialog:

class Widget(QtGui.QDialog):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent)

Then create a function for class Widget with a static method. Function will get parent to dialog window and return text from edit field:

@staticmethod
def getData(parent = None):
    dialog = Widget(parent)
    dialog.exec_()
    return dialog.returnAnswer1()

Then call the window with passing a value:

def main():
    app = QtGui.QApplication([])
    window = Widget()
    print window.getData()  # window is value from edit field

Also, you need delete self.show() from class.

Full code: https://gist.github.com/gitex/83b06e8ceaac18ad5dec2d332ed6cbaa

edited Apr 17 '16 at 15:46

answered Apr 17 '16 at 12:43

JRazor

2,707
18
27

Hi JRazor, thanks a lot for helping out here... I added `print(window)` after your `window = Widget.getData()` but after writing something in the edit field and hitting the Apply button nothings happens... would you know what is wrong then? – chriselswede Apr 17 '16 at 15:19
Great it works! But when I tried to have more than one question in the same dialog box, the dialog opens twice. Any idea how to solve that? Please see my code in your [github](https://gist.github.com/gitex/83b06e8ceaac18ad5dec2d332ed6cbaa) – chriselswede Apr 18 '16 at 20:09
@chan: Read the PyQt documentation before using them. This will save you a lot of questions. I added to Gist second field. – JRazor Apr 19 '16 at 10:42
don't use getData second time – JRazor Apr 19 '16 at 10:52
Thanks a lot for your help! In the end I used a list of answers out from the static method (I added the final solution in my section above). – chriselswede Apr 21 '16 at 07:48

How to use QtGui in PyQt4 to collect input variables to a python program?

1 Answers1