Question

from PyQt4.QtGui import QApplication, QMainWindow, QPushButton, \
        QLabel, QVBoxLayout, QWidget
from PyQt4 import QtGui
import sys

import subprocess

class MainWindow1(QMainWindow):
    def __init__(self, parent=None):
        QMainWindow.__init__(self, parent) 
        button = QPushButton('NotePad')

        label = QLabel('MainWindow1')

        centralWidget = QWidget()
        vbox = QVBoxLayout(centralWidget)
        vbox.addWidget(label)
        vbox.addWidget(button)
        self.setCentralWidget(centralWidget)

        button.clicked.connect(self.LaunchNotepad)

    # Some code here - including import subprocess
    def LaunchNotepad(self):

        returncode = subprocess.call(['python', 'notepad.py'])




if __name__ == '__main__':
    app = QApplication(sys.argv)
    mainwindow1 = MainWindow1()
    mainwindow1.show()
    sys.exit(app.exec_())

that code creates a main window with a button, when i press the button i would like it to import my file called “notepad”, (I think it does) however it opens it and closes it straight away. I need to be able to use the program notepad until i close it in which case it should revert back to the original window. Eventually i will have 3 or 4 buttons importing 3 or 4 different programs

I dont think there is an error in notepad because when i only have the statement “import notepad” it runs perfectly

note: the notepad file is just a simple text program (much like the “notepad” program on windows pcs)

thanks in advance

edit here is note pad code:

import sys
import os
import datetime as dt
from PyQt4 import QtGui
from PyQt4 import *


class Notepad(QtGui.QMainWindow):
    def __init__(self):
        super(Notepad, self).__init__()
        self.initUI()






    def initUI(self):
        newAction = QtGui.QAction('New', self)
        newAction.setShortcut('Ctrl+N')
        newAction.setStatusTip('Create new file')
        newAction.triggered.connect(self.newFile)  
        saveAction = QtGui.QAction('Save', self)
        saveAction.setShortcut('Ctrl+S')
        saveAction.setStatusTip('Save current file')
        saveAction.triggered.connect(self.saveFile)
        openAction = QtGui.QAction('Open', self)
        openAction.setShortcut('Ctrl+O')
        openAction.setStatusTip('Open a file')
        openAction.triggered.connect(self.openFile)

        closeAction = QtGui.QAction('Close', self)
        closeAction.setShortcut('Ctrl+Q')
        closeAction.setStatusTip('Close Notepad')
        closeAction.triggered.connect(self.close)
        menubar = self.menuBar()

        fileMenu = menubar.addMenu('&File')
        fileMenu.addAction(newAction)
        fileMenu.addAction(saveAction)
        fileMenu.addAction(openAction)
        fileMenu.addAction(closeAction)

        #help menu
        helpMenu = menubar.addMenu('&Help')
        aboutAction = QtGui.QAction('About', self)
        aboutAction.setShortcut('Ctrl+A')
        aboutAction.setStatusTip('About')
        helpMenu.addAction(aboutAction)
        aboutAction.triggered.connect(self.about) 

        self.text = QtGui.QTextEdit(self)

        self.setCentralWidget(self.text)
        self.setGeometry(300,300,300,300)
        self.setWindowTitle('Notepad')


        self.show()
        self.statusBar()










    def newFile(self):
        self.text.clear()

    def saveFile(self):
        filename = QtGui.QFileDialog.getSaveFileName(self, 'Save File', os.getenv('HOME'))
        f = open(filename, 'w')
        filedata = self.text.toPlainText()
        f.write(filedata)
        f.close()

    def openFile(self):
        filename = QtGui.QFileDialog.getOpenFileName(self, 'Open File', os.getenv('HOME'))
        f = open(filename, 'r')
        filedata = f.read()
        self.text.setText(filedata)
        f.close()

        self.setGeometry(300,300,300,300)
        self.setWindowTitle('Notepad')
    self.show()
    def closeEvent(self, event):


        reply = QtGui.QMessageBox.question(self, 'Message',
            "Are you sure to quit?", QtGui.QMessageBox.Yes | 
            QtGui.QMessageBox.No, QtGui.QMessageBox.No)

        if reply == QtGui.QMessageBox.Yes:
            event.accept()
        else:
            event.ignore()
    def about(self, event):
        reply = QtGui.QMessageBox.question(self, 'About Task Manager',
            "This is a notepad todo list program written by craig murch")


        return Notepad



if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    notepad = Notepad()

    sys.exit(app.exec_())

EDIT: The edited code above now does want i want it to do however it loads the cmd as well which i dont want to, how do i stop it loading the cmd?

Answer 1

Well, in your Notepad code you have

sys.exit(app.exec_())

This will close the entire process. So if you’re importing it from your parent window then yeah, it should be closing your application.

Also, regardless of which GUI framework you use it’s always a bad idea to mix mainloops in the same process. Instead, you should use subprocess to call your other application:

# Some code here - including import subprocess
import os
def LaunchNotepad(self):
    self.DoSomething() #Or whatever you want to do before your program launches
    returncode = subprocess.call(['pythonw', 'notepad.py'],
                                 stdout=open(os.devnull, 'w'),
                                 stderr=open(os.devnull, 'w'))
    self.ShowMe() #Won't run until notepad finishes
    if not returncode:
        self.ShowError("Notepad exited abnormally!")

That’s a pretty basic example of what you could do.