How do I open sub window after I click on button on main screen in PyQt4

Question

HI I am trying to make a simple converter. I have used PyQt4 designed to make the Gui I want to know how launch a new window after I click on the individual button.

Answer 1

Each GUI form that you create in Qt Designer needs to be converted into a python module using pyuic. So, to start with, you need to do the same for currency.ui that you did for window_main.

Now you can import your currency window class into mainscreen.py, and connect a button to handler so you can display it.

The code would look something like this:

from PyQt4 import QtCore, QtGui
from window_main import Ui_MainWindow
from currency import Ui_CurrencyWindow

class CurrencyWindow(QtGui.QMainWindow, Ui_CurrencyWindow):
    def __init__(self, parent=None):
        super(CurrencyWindow, self).__init__(parent)
        self.setAttribute(QtCore.Qt.WA_DeleteOnClose)
        self.setupUi(self)

class MainScreen(QtGui.QMainWindow, Ui_MainWindow):
    def __init__(self, parent=None):
        super(MainScreen, self).__init__(parent)
        self.setupUi(self)
        self.currencyButton.clicked.connect(self.handleCurrencyButton)

    def handleCurrencyButton(self):
        window = CurrencyWindow(self)
        window.show()

After looking at this example code, it will probably occur to you that you are going to end up importing a lot of modules, and have a lot of boiler-plate code to write for each one of them (which is not much fun).

So I would advise you to consider changing your GUI design, so that you have one main window containing a tabwidget, and then have a separate tab for each of your converters. This will not only make your application much easier to write, but it should also make it a lot nicer to use.

Answer 2

Make two programs: main_win.py and second_win.py, then in main_win.py put this lines:

from os import system as sh               //In the begin

def openewin(self):                       //In the class main_win
    sh("python second_win.py") 

Ready, just connect the push button to function openewin!

Answer 3

I'm making my bachelor thesis in PyQt4. First I also wanted to use the designer (generating code is nice), but afterall I was not using it during my work. Maybe it's a matter of taste. But for your question (I did this without the QtDesigner):

Let's say we have a main window class:

import sys
from PyQt4 import QtCore, QtGui

class mainscreen(QtGui.QMainWindow):
        def __init__(self, parent=None):
            super(mainscreen,self).__init__(parent)

            self.button = QtGui.QPushButton("push")
            self.button.clicked.connect(self.pushed)

        @pyqtSlot()
        def pushed(self):
            # in this section here you can create the new window and show it


 qApp = QtGui.QApplication(sys.argv)
    aw = mainscreen()
    aw.show()
    sys.exit(qApp.exec_())

There are some good tutorials (http://zetcode.com/gui/pyqt4/ helped me getting started).