Develop Reference

To turn back from 2nd window to 1st window (different files)

An application is being created with a large number of different windows.
The bottom line is that I am trying to get from the main window (by clicking button) to the client window. There is "Back" button in the clients window, which should return the user to the main window.
Both codes are in different files. The problem occurs at the stage of pressing the "Customers" button (Process finished with exit code -1073740791 (0xC0000409)).
Moreover, if everything is in one file, then everything works fine. But only here the program is not planned to be small, so I don't want to put a huge code in one file.
Welcome_Screen.py
import sys
from PyQt5.uic import loadUi
from PyQt5 import QtWidgets, QtGui
from PyQt5.QtWidgets import QDialog, QApplication
import Customers
class WelcomeScreen(QDialog):
def __init__(self):
super(WelcomeScreen, self).__init__()
loadUi('screens/welcomescreen.ui', self)
self.CustomerData.clicked.connect(self.go_to_CustomerData)
def go_to_CustomerData(self):
client = Customers.CustomerScreen()
widget.addWidget(client)
widget.setCurrentIndex(widget.currentIndex() + 1)
# main
app = QApplication(sys.argv)
app.setWindowIcon(QtGui.QIcon('Icons/MainIcon.png'))
app.setApplicationDisplayName('Bonus Program')
welcome = WelcomeScreen()
widget = QtWidgets.QStackedWidget()
widget.addWidget(welcome)
widget.setFixedWidth(600)
widget.setFixedHeight(475)
widget.show()
try:
sys.exit(app.exec_())
except:
print("Exiting")
Customers.py
import sys
from PyQt5.uic import loadUi
from PyQt5 import QtWidgets, QtCore, QtGui
from PyQt5.QtWidgets import QDialog, QApplication, QWidget, QMessageBox, QTableWidget, QTableWidgetItem, QTableView
from PyQt5.QtSql import QSqlDatabase, QSqlTableModel, QSqlQuery
from PyQt5.QtGui import QIcon
import Welcome_Screen as ws
import sqlite3
db_path = 'Bonus_db.sqlite'
class CustomerScreen(QDialog):
def __init__(self):
super(CustomerScreen, self).__init__()
loadUi("screens/customerscreen.ui", self)
self.back_btn.setIcon(QIcon('Icons/Back.png'))
self.back_btn.setIconSize(QtCore.QSize(45, 60))
self.back_btn.clicked.connect(self.go_Back_to_WelcomeScreen)
# self.SoldTos.clicked.connect(self.gotoSoldTos)
def go_Back_to_WelcomeScreen(self):
welcome = ws.WelcomeScreen()
ws.widget.addWidget(welcome)
ws.widget.setCurrentIndex(ws.widget.currentIndex() + 1)
Customer_app = QApplication(sys.argv)
cust_window = CustomerScreen()
cust_window.show()
sys.exit(Customer_app.exec_())

PyQt5 opening new window w/ if else

I'm designing window with PyQt5 and QtDesigner. I made maindemo.py, maindemo.ui, mainfail.py, mainfail.ui.
import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QWidget, QPushButton, QGraphicsView, QLabel, QMenuBar, QMenu, QStatusBar, QAction, qApp, QMessageBox
from PyQt5 import uic, QtCore
form_class = uic.loadUiType("maindemo.ui")[0]
class OpeningWindow(QMainWindow, form_class):
def __init__(self):
super().__init__()
self.setupUi(self)
self.initUI()
def initUI(self):
self.setWindowTitle('Qomics')
self.btn_survival.setToolTip('Survival Analysis')
self.btn_drug.setToolTip('Drug Analysis')
self.btn_CRISPR.setToolTip('CRISPR Analysis')
self.btn_cellline.setToolTip('Cell Line')
self.btn_survival.clicked.connect(self.open_SurvivalMainWindow)
self.btn_drug.clicked.connect(self.open_DrugWindow)
self.btn_CRISPR.clicked.connect(self.open_sgRNAWindow)
self.btn_cellline.clicked.connect(self.open_CellLineWindow)
actionExit = QAction('&Exit', self)
actionExit.setShortcut('Ctrl+Q')
actionExit.setStatusTip('Exit Application')
actionExit.triggered.connect(qApp.quit)
self.statusBar().showMessage('abcd')
self.setGeometry(200, 100, 800, 530)
self.show()
def openSurvivalMainWindow(self):
open_SurvivalMainWindow = SurvivalMainWindow()
open_SurvivalMainWindow.show()
def openDrugWindow(self):
open_DrugWindow = DrugWindow()
open_DrugWindow.show()
def opensgRNAWindow(self):
open_sgRNAWindow = sgRNAWindow()
open_sgRNAWindow.show()
def openCellLineWindow(self):
open_CellLineWindow = scatterWindow()
open_CellLineWindow.show()
above code is maindemo.py
what I want to do is clicking btn_drug, btn_sgRNA, btn_cellline connects to new window(with mainfail.py, mainfail.ui)
Only btn_survival connects to the real function and other buttons connects to mainfail window.
I tried to use if, else... but I couldn't write proper code..
I wrote a code but it doesn't work.
if openSurvivalMainWindow():
else:
openMainFailWindow.show()

Not clear what you want, but here an example of a multi window
import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QWidget, QPushButton, QGraphicsView, QLabel, QMenuBar, QMenu, QStatusBar, QAction, qApp, QMessageBox
from PyQt5 import uic, QtCore
from PyQt5.uic import loadUiType
login, _ = loadUiType('login.ui')
registration,_ = loadUiType('registration.ui')
class Register(QMainWindow, registration):
def __init__(self):
QWidget.__init__(self)
self.setupUi(self)
self.pushButton_24.clicked.connect(self.adding_users)
self.pushButton_25.clicked.connect(self.return_login)
def return_login(self):
self.window2 = Login()
self.close()
self.window2.show()
class Login(QWidget, login):
def __init__(self):
QWidget.__init__(self)
self.setupUi(self)
self.pushButton.clicked.connect(self.Handel_Login)
self.pushButton_2.clicked.connect(self.registrations)
def registrations(self):
self.window2 = Register()
self.close()
self.window2.show()
######
#....
######
if __name__ == '__main__':
app = QApplication(sys.argv)
app.setStyle('Fusion')
window = Login()
#window = MainApp()
window.show()
sys.exit(app.exec_())
With this your application will go first to the login page and if you push the button 2 you will go to the registration page and of course the log in page will be closed

Can I implement a random font selection?

I have a program that displays some message on a label (using QtDesigner):
from PyQt5 import uic
from PyQt5.QtWidgets import QApplication, QWidget, QMainWindow
class MyWidget(QMainWindow):
def __init__(self):
super().__init__()
uic.loadUi('main1.ui', self)
self.run()
def run(self):
self.label.setText('Message')
app = QApplication(sys.argv)
ex = MyWidget()
ex.show()
sys.exit(app.exec_())
This message displays in the selected font in the QtDesigner, StyleSheet of my label:
The question is: What can I do to make this font be randomly selected? Is it possible? (Perfect case: every time i run my program it shows my message in some randomly selected font)

You can obtain all the available families through the families() method of QFontDatabase, choose one randomly, build a QFont and set it in the QLabel:
import random
import sys
from PyQt5 import uic
from PyQt5.QtGui import QFont, QFontDatabase
from PyQt5.QtWidgets import QApplication, QWidget, QMainWindow
class MyWidget(QMainWindow):
def __init__(self):
super().__init__()
uic.loadUi("main1.ui", self)
db = QFontDatabase()
family = random.choice(db.families())
print(family)
font = db.font(family, "", 72)
# also random style:
# style = random.choice(db.styles(family))
# font = db.font(family, style, 72)
self.label.setFont(font)
self.run()
def run(self):
self.label.setText("Message")
if __name__ == "__main__":
app = QApplication(sys.argv)
ex = MyWidget()
ex.show()
sys.exit(app.exec_())

PyQt5 5.9 , setWindowIcon( QIcon(*WEB_LINK*) )

Hi, I have an issue with my PyQt5 setWindowIcon.
When I try to set my window icon from a local image, it works perfectly. But when I try to put a online link like:
setWindowIcon( QIcon("https://www.google.ge/images/branding/product/ico/googleg_lodp.ico") )
it does not work. What to do? Its 32x32 ico btw.
~Thanks

You have to use QNetworkAccessManager and manually download image from url. Then read bytes from response, create a QPixmap (beacuse it has loadFromData method) and initialize a QIcon from QPixmap.
And after that you will be able to set window icon.
import sys
from PyQt5.QtCore import QUrl
from PyQt5.QtGui import QIcon, QPixmap
from PyQt5.QtNetwork import QNetworkAccessManager, QNetworkRequest
from PyQt5.QtWidgets import QApplication, QWidget, QLabel, QVBoxLayout
ICON_IMAGE_URL = "https://www.google.ge/images/branding/product/ico/googleg_lodp.ico"
class MainWindow(QWidget):
def __init__(self):
QWidget.__init__(self)
self.label = QLabel('Image loading demo')
self.vertical_layout = QVBoxLayout()
self.vertical_layout.addWidget(self.label)
self.setLayout(self.vertical_layout)
self.nam = QNetworkAccessManager()
self.nam.finished.connect(self.set_window_icon_from_response)
self.nam.get(QNetworkRequest(QUrl(ICON_IMAGE_URL)))
def set_window_icon_from_response(self, http_response):
pixmap = QPixmap()
pixmap.loadFromData(http_response.readAll())
icon = QIcon(pixmap)
self.setWindowIcon(icon)
if __name__ == '__main__':
app = QApplication(sys.argv)
window = MainWindow()
window.show()
sys.exit(app.exec_())

PyQt5 program does not displaying the widgets

I was writing a pyqt5 program for expression evaluator but after running the program i am not able to see any widgets and getting blank window
def expressionevaluator():
import sys
from PyQt5 import QtWidgets
from PyQt5 import QtCore
from PyQt5 import QtGui
from PyQt5.QtWidgets import QApplication, QWidget,QMainWindow
class Window(QtWidgets.QMainWindow):
def __init__(self):
super(Window,self).__init__()
self.setGeometry(50,50,500,300)
self.setWindowTitle("PyQt Tutorial")
self.setWindowIcon=QtGui.QIcon('pyqt_example2.PNG')
self.home()
def ExitForm(self):
sys.exit()
def home(self):
vbox=QtWidgets.QVBoxLayout()
textbrowser=QtWidgets.QTextBrowser()
lineedit=QtWidgets.QLineEdit()
btn=QtWidgets.QPushButton("QUIT")
btn.clicked.connect(self.close)
vbox.addWidget(textbrowser)
vbox.addWidget(lineedit)
vbox.addWidget(btn)
self.setLayout(vbox)
self.show()
if __name__=="__main__":
app=QApplication(sys.argv)
GUI=Window()
sys.exit(app.exec_())
expressionevaluator()
So what should I do ?

Just running your code I got a widget showing up in my screen, but its components didn't show up. Instead of setting a layout of a QMainWindow try to have a central widget (QWidget) set its layout with its components than set the QMainWindow central widget with this widget. There you go, now you have all working fine.
You had problems with the layout because QMainWindow behaves differently from others Widgets, it has its own layout and many other default behaviors, central widget is the reason why nothing was showing up inside your main window.
def expressionevaluator():
import sys
from PyQt5.QtGui import QIcon
from PyQt5.QtWidgets import QApplication
from PyQt5.QtWidgets import QLineEdit
from PyQt5.QtWidgets import QMainWindow
from PyQt5.QtWidgets import QPushButton
from PyQt5.QtWidgets import QTextBrowser
from PyQt5.QtWidgets import QVBoxLayout
from PyQt5.QtWidgets import QWidget
class Window(QMainWindow):
def __init__(self):
super(Window,self).__init__()
self.setGeometry(50,50,500,300)
self.setWindowTitle("PyQt Tutorial")
self.setWindowIcon = QIcon('pyqt_example2.PNG')
self.home()
def ExitForm(self):
sys.exit()
def home(self):
vbox = QVBoxLayout()
textbrowser = QTextBrowser()
lineedit = QLineEdit()
btn = QPushButton("QUIT")
central_widget = QWidget()
central_widget.setLayout(vbox)
btn.clicked.connect(self.close)
vbox.addWidget(textbrowser)
vbox.addWidget(lineedit)
vbox.addWidget(btn)
self.setCentralWidget(central_widget)
self.show()
if __name__=="__main__":
app = QApplication(sys.argv)
GUI = Window()
GUI.show()
sys.exit(app.exec_())
expressionevaluator()
Note: There are many improvements in the structure of your code you could do, I just changed as less as I could to make it work, for example try to not import all the modules at once, import just what you need for example QIcon, QLineEdit and so on, instead of the whole QtWidgets, or QtCore...

Following code works well:
import sys
from PyQt5.QtGui import QIcon
from PyQt5.QtWidgets import QApplication
from PyQt5.QtWidgets import QLineEdit
from PyQt5.QtWidgets import QMainWindow
from PyQt5.QtWidgets import QPushButton
from PyQt5.QtWidgets import QTextBrowser
from PyQt5.QtWidgets import QVBoxLayout
from PyQt5.QtWidgets import QWidget
class Window(QMainWindow):
def __init__(self):
super(Window,self).__init__()
self.setGeometry(50,50,500,300)
self.setWindowTitle("PyQt Tutorial")
self.setWindowIcon = QIcon('pyqt_example2.PNG')
self.home()
def ExitForm(self):
sys.exit()
def home(self):
vbox = QVBoxLayout()
textbrowser = QTextBrowser()
lineedit = QLineEdit()
btn = QPushButton("QUIT")
central_widget = QWidget()
central_widget.setLayout(vbox)
btn.clicked.connect(self.ExitForm)
vbox.addWidget(textbrowser)
vbox.addWidget(lineedit)
vbox.addWidget(btn)
self.setCentralWidget(central_widget)
self.show()
if __name__=="__main__":
app = QApplication(sys.argv)
GUI = Window()
GUI.show()
sys.exit(app.exec_())