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Qt: Dead lock detected - Sender is QPushButton(), receiver is PyQtSlotProxy() - for specific indexes in a QPushButton list

I am new to pyqt, and I tried to make an application window that contains a list of buttons that are able to toggle a different window. Since I want the number of these buttons to be of a varying quantity, I created a list of QPushButton elements for iterating over them, creating as many as defined by the length of the list, nevertheless I noticed a very weird behavior :
The following code ...
import sys
from random import randint
from PyQt5 import QtWidgets
class AnotherWindow(QtWidgets.QWidget):
"""
This "window" is a QWidget. If it has no parent,
it will appear as a free-floating window.
"""
def __init__(self):
super().__init__()
layout = QtWidgets.QVBoxLayout()
self.label = QtWidgets.QLabel("Another Window % d" % randint(0, 100))
layout.addWidget(self.label)
self.setLayout(layout)
class MainWindow(QtWidgets.QMainWindow):
def __init__(self,windows):
super().__init__()
self.windows=[]
self.buttons=[]
l=QtWidgets.QVBoxLayout()
for i in range(len(windows)):
window=AnotherWindow()
self.windows.append(window)
button=QtWidgets.QPushButton(f'window {windows[i]}')
print(i," ",button)
self.buttons.append(button)
self.buttons[i].clicked.connect(self.toggle_window,i)
l.addWidget(self.buttons[i])
w = QtWidgets.QWidget()
w.setLayout(l)
self.setCentralWidget(w)
print(len(self.windows))
def toggle_window(self,i):
if self.windows[i].isVisible():
self.windows[i].hide()
else:
self.windows[i].show()
if __name__=="__main__":
app = QtWidgets.QApplication(sys.argv)
windows=[0,1,2,3]
windows=[str(i) for i in windows]
print(windows)
w = MainWindow(windows)
w.show()
app.exec()
produced the following error but only when the 4rth button (window 3) is pressed.
Qt: Dead lock detected while activating a BlockingQueuedConnection: Sender is QPushButton( ... ), receiver is PyQtSlotProxy( ... )
In effort to validate the code, I tried to narrow the list into a linear declaration of a static number of QPushButton instances, indicating that the issue occurs, only when I try to put the buttons on a list. For instance, the following script does not present any similar unpredictable behavior:
import sys
from random import randint
from PyQt5 import QtWidgets
class AnotherWindow(QtWidgets.QWidget):
"""
This "window" is a QWidget. If it has no parent,
it will appear as a free-floating window.
"""
def __init__(self):
super().__init__()
layout = QtWidgets.QVBoxLayout()
self.label = QtWidgets.QLabel("Another Window % d" % randint(0, 100))
layout.addWidget(self.label)
self.setLayout(layout)
class MainWindow(QtWidgets.QMainWindow):
def __init__(self):
super().__init__()
self.window0 = AnotherWindow()
self.window1 = AnotherWindow()
self.window2 = AnotherWindow()
self.window3 = AnotherWindow()
l = QtWidgets.QVBoxLayout()
button0 = QtWidgets.QPushButton("window 0")
button0.clicked.connect(self.toggle_window0)
l.addWidget(button0)
button1 = QtWidgets.QPushButton("window 1")
button1.clicked.connect(self.toggle_window1)
l.addWidget(button1)
button2 = QtWidgets.QPushButton("window 2")
button2.clicked.connect(self.toggle_window2)
l.addWidget(button2)
button3 = QtWidgets.QPushButton("window 3")
button3.clicked.connect(self.toggle_window3)
l.addWidget(button3)
w = QtWidgets.QWidget()
w.setLayout(l)
self.setCentralWidget(w)
def toggle_window0(self, checked):
if self.window0.isVisible():
self.window0.hide()
else:
self.window0.show()
def toggle_window1(self):
if self.window1.isVisible():
self.window1.hide()
else:
self.window1.show()
def toggle_window2(self):
if self.window2.isVisible():
self.window2.hide()
else:
self.window2.show()
def toggle_window3(self, checked):
if self.window3.isVisible():
self.window3.hide()
else:
self.window3.show()
if __name__=="__main__":
app = QtWidgets.QApplication(sys.argv)
w = MainWindow()
w.show()
app.exec()
To test it further, I extended the list to a list of random lengths (more than 10), where I reassured that the issue persist for specific indexes each time. For example if I create 20 buttons using the first approach, the same bug appears for - the 4rth, the 12fth and the last index exclusively - but not for the rest of them. I even tested it on a different machine. Having also searched in forums, I could not find a solution.
Do I do anything completely wrong here? Does anyone understands better to indicate why is this happening?
I kindly thank you in advance!
Environment: Ubuntu 22.04
Pyqt version : 1.9 (under conda)

Your problem is the following:
self.buttons[i].clicked.connect(self.toggle_window,i)
You are passing i as second argument to connect and expect the toggle_window function to be called with this argument. This is not happening. In toggle_window, i will always be False. See musicamente's comment regarding what this second argument to connect does.
What you should do instead is connect the button click to a function of your window object. From there, you can of course do a callback to a function of your main window as illustrated below:
import sys
from random import randint
from PyQt5 import QtWidgets
class AnotherWindow(QtWidgets.QWidget):
def __init__(self, parent, i):
super().__init__()
self.parent = parent
self.i = i
layout = QtWidgets.QVBoxLayout()
self.label = QtWidgets.QLabel("Another Window {}".format(i))
layout.addWidget(self.label)
self.setLayout(layout)
def toggle(self):
print("Toggling windows {}".format(self.i))
if self.isVisible():
self.hide()
self.parent.window_toggled(self.i, False)
else:
self.show()
self.parent.window_toggled(self.i, True)
class MainWindow(QtWidgets.QMainWindow):
def __init__(self, windows):
super().__init__()
self.windows=[]
self.buttons=[]
l=QtWidgets.QVBoxLayout()
for i,title in enumerate(windows):
window=AnotherWindow(self, i)
self.windows.append(window)
button=QtWidgets.QPushButton(title)
button.clicked.connect(window.toggle)
l.addWidget(button)
self.buttons.append(button)
w = QtWidgets.QWidget()
w.setLayout(l)
self.setCentralWidget(w)
def window_toggled(self, i, visible):
print("Window {} is now {}".format(i, "visible" if visible else "hidden"))
if __name__=="__main__":
app = QtWidgets.QApplication(sys.argv)
windows = ["window {}".format(i) for i in range(12)]
w = MainWindow(windows)
w.show()
app.exec()

PyQt5 removing button

In the list_widget I have added a add button I also want to add a remove button which asks which item you wants to remove and remove the chosen item. I was trying it to do but I didn't had any idea to do so .Also, please explain the solution I am a beginner with pyqt5 or I'd like to say absolute beginner.
from PyQt5 import QtWidgets
from PyQt5.QtWidgets import QApplication,QMainWindow,
QListWidget, QListWidgetItem
import sys
class MyWindow(QMainWindow):
def __init__(self):
super(MyWindow, self).__init__()
self.x = 200
self.y = 200
self.width = 500
self.length = 500
self.setGeometry(self.x, self.y, self.width,
self.length)
self.setWindowTitle("Stock managment")
self.iniTUI()
def iniTUI(self):
# buttons
self.b1 = QtWidgets.QPushButton(self)
self.b1.setText("+")
self.b1.move(450, 100)
self.b1.resize(50, 25)
self.b1.clicked.connect(self.take_inputs)
# This is the button I want to define.
self.btn_minus = QtWidgets.QPushButton(self)
self.btn_minus.setText("-")
self.btn_minus.move(0, 100)
self.btn_minus.resize(50, 25)
# list
self.list_widget = QListWidget(self)
self.list_widget.setGeometry(120, 100, 250, 300)
self.item1 = QListWidgetItem("A")
self.item2 = QListWidgetItem("B")
self.item3 = QListWidgetItem("C")
self.list_widget.addItem(self.item1)
self.list_widget.addItem(self.item2)
self.list_widget.addItem(self.item3)
self.list_widget.setCurrentItem(self.item2)
def take_inputs(self):
self.name, self.done1 =
QtWidgets.QInputDialog.getText(
self, 'Add Item to List', 'Enter The Item you want
in
the list:')
self.roll, self.done2 = QtWidgets.QInputDialog.getInt(
self, f'Quantity of {str(self.name)}', f'Enter
Quantity of {str(self.name)}:')
if self.done1 and self.done2:
self.item4 = QListWidgetItem(f"{str(self.name)}
Quantity{self.roll}")
self.list_widget.addItem(self.item4)
self.list_widget.setCurrentItem(self.item4)
def clicked(self):
self.label.setText("You clicked the button")
self.update()
def update(self):
self.label.adjustSize()
def clicked():
print("meow")
def window():
apk = QApplication(sys.argv)
win = MyWindow()
win.show()
sys.exit(apk.exec_())
window()

The core issue here is the lack of separation of the view and the data. This makes it very hard to reason about how to work with graphical elements. You will almost certainly want to follow the Model View Controller design paradigm https://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller
which offers a systematic way to handle this separation.
Once you do so, it immediately becomes very straight forward how to proceed with the question: You essentially just have a list, and you either want to add a thing to this list, or remove one based on a selection.
I include an example here which happens to use the built-in classes QStringListModel and QListView in Qt5, but it is simple to write your own more specialized widgets and models. They all just use a simple signal to emit to the view that it needs to refresh the active information.
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
import sys
class StuffViewer(QMainWindow):
def __init__(self, model):
super().__init__()
self.setWindowTitle("Stock managment")
# 1: Use layouts.
hbox = QHBoxLayout()
widget = QWidget()
widget.setLayout(hbox)
self.setCentralWidget(widget)
# 2: Don't needlessly store things in "self"
vbox = QVBoxLayout()
add = QPushButton("+")
add.clicked.connect(self.add_new_stuff)
vbox.addWidget(add)
sub = QPushButton("-")
sub.clicked.connect(self.remove_selected_stuff)
vbox.addWidget(sub)
vbox.addStretch(1)
hbox.addLayout(vbox)
# 3: Separate the view of the data from the data itself. Use Model-View-Controller design to achieve this.
self.model = model
self.stuffview = QListView()
self.stuffview.setModel(self.model)
hbox.addWidget(self.stuffview)
def add_new_stuff(self):
new_stuff, success = QInputDialog.getText(self, 'Add stuff', 'Enter new stuff you want')
if success:
self.stuff.setStringList(self.stuff.stringList() + [new_stuff])
def remove_selected_stuff(self):
index = self.stuffview.currentIndex()
all_stuff = self.stuff.stringList()
del all_stuff[index.column()]
self.stuff.setStringList(all_stuff)
def window():
apk = QApplication(sys.argv)
# Data is clearly separated:
# 4: Never enumerate variables! Use lists!
stuff = QStringListModel(["Foo", "Bar", "Baz"])
# The graphical components is just how you interface with the data with the user!
win = StuffViewer(stuff)
win.show()
sys.exit(apk.exec_())
window()

How to have two widgets in one Main window

I am trying the whole morning already to fix that.
So I have a PyQt Main Window where I want to display two widgets.
In the first widget there are articles listed (which works so far).
When I click on them until now a QMessageBox is opening, but I want that
a second widget is opening where I can read the RSS Feed.
But this is not working. See Code below:
class ArticleWidgets(QWidget):
def __init__(self, *args):
super().__init__(*args)
self.setGeometry(610, 610, 600, 600)
self.initUi()
def initUi(self):
self.box = QHBoxLayout(self)
def show(self, feed=None):
self.title = QLabel()
self.summary = QLabel()
self.link = QLabel()
if feed:
self.title.setText(feed[0])
self.summary.setText(feed[1])
self.link.setText(feed[2])
self.box.addWidget(self.title)
self.box.addWidget(self.summary)
self.box.addWidget(self.link)
self.setLayout(self.box)
class TitleWidgets(QWidget):
def __init__(self, *args):
super().__init__(*args)
self.setGeometry(10, 10, 600, 600)
self.initUi()
def initUi(self):
vbox = QHBoxLayout(self)
self.titleList = QListWidget()
self.titleList.itemDoubleClicked.connect(self.onClicked)
self.titleList.setGeometry(0, 0, 400, 400)
self.news = ANFFeed()
for item in self.news.all_feeds:
self.titleList.addItem(item[0])
vbox.addWidget(self.titleList)
def onClicked(self, item):
feeds = self.news.all_feeds
id = 0
for elem in range(len(feeds)):
if feeds[elem][0] == item.text():
id = elem
summary = feeds[id][1] + '\n\n'
link = feeds[id][2]
if feeds and id:
#ANFApp(self).show_articles(feeds[id])
show = ANFApp()
show.show_articles(feed=feeds[id])
QMessageBox.information(self, 'Details', summary + link)
class ANFApp(QMainWindow):
def __init__(self, *args):
super().__init__(*args)
self.setWindowState(Qt.WindowMaximized)
self.setWindowIcon(QIcon('anf.png'))
self.setAutoFillBackground(True)
self.anfInit()
self.show()
def anfInit(self):
self.setWindowTitle('ANF RSS Reader')
TitleWidgets(self)
#article_box = ArticleWidgets(self)
exitBtn = QPushButton(self)
exitBtn.setGeometry(600, 600, 100, 50)
exitBtn.setText('Exit')
exitBtn.setStyleSheet("background-color: red")
exitBtn.clicked.connect(self.exit)
def show_articles(self, feed=None):
present = ArticleWidgets()
present.show(feed)
def exit(self):
QCoreApplication.instance().quit()

Solution using Pyqtgraph's Docks and QTextBrowser
Here is a code trying to reproduce your sketch. I used the Pyqtgraph module (Documentation here: Pyqtgraph's Documentation and Pyqtgraph's Web Page) because its Dock widget is easier to use and implement from my perspective.
You must install the pyqtgraph module before trying this code:
import sys
from PyQt5 import QtGui, QtCore
from pyqtgraph.dockarea import *
class DockArea(DockArea):
## This is to prevent the Dock from being resized to te point of disappear
def makeContainer(self, typ):
new = super(DockArea, self).makeContainer(typ)
new.setChildrenCollapsible(False)
return new
class MyApp(QtGui.QMainWindow):
def __init__(self):
QtGui.QMainWindow.__init__(self)
central_widget = QtGui.QWidget()
layout = QtGui.QVBoxLayout()
central_widget.setLayout(layout)
self.setCentralWidget(central_widget)
label = QtGui.QLabel('This is a label, The widgets will be below')
label.setMaximumHeight(15)
## The DockArea as its name says, is the are where we place the Docks
dock_area = DockArea(self)
## Create the Docks and change some esthetic of them
self.dock1 = Dock('Widget 1', size=(300, 500))
self.dock2 = Dock('Widget 2', size=(400, 500))
self.dock1.hideTitleBar()
self.dock2.hideTitleBar()
self.dock1.nStyle = """
Dock > QWidget {
border: 0px solid #000;
border-radius: 0px;
}"""
self.dock2.nStyle = """
Dock > QWidget {
border: 0px solid #000;
border-radius: 0px;
}"""
self.button = QtGui.QPushButton('Exit')
self.widget_one = WidgetOne()
self.widget_two = WidgetTwo()
## Place the Docks inside the DockArea
dock_area.addDock(self.dock1)
dock_area.addDock(self.dock2, 'right', self.dock1)
## The statment above means that dock2 will be placed at the right of dock 1
layout.addWidget(label)
layout.addWidget(dock_area)
layout.addWidget(self.button)
## Add the Widgets inside each dock
self.dock1.addWidget(self.widget_one)
self.dock2.addWidget(self.widget_two)
## This is for set the initial size and posotion of the main window
self.setGeometry(100, 100, 600, 400)
## Connect the actions to functions, there is a default function called close()
self.widget_one.TitleClicked.connect(self.dob_click)
self.button.clicked.connect(self.close)
def dob_click(self, feed):
self.widget_two.text_box.clear()
## May look messy but wat i am doing is somethin like this:
## 'Title : ' + feed[0] + '\n\n' + 'Summary : ' + feed[1]
self.widget_two.text_box.setText(
'Title : ' + feed[0]\
+ '\n\n' +\
'Summary : ' + feed[1]
)
class WidgetOne(QtGui.QWidget):
## This signal is created to pass a "list" when it (the signal) is emited
TitleClicked = QtCore.pyqtSignal([list])
def __init__(self):
QtGui.QWidget.__init__(self)
self.layout = QtGui.QVBoxLayout()
self.setLayout(self.layout)
self.titleList = QtGui.QListWidget()
self.label = QtGui.QLabel('Here is my list:')
self.layout.addWidget(self.label)
self.layout.addWidget(self.titleList)
self.titleList.addItem(QtGui.QListWidgetItem('Title 1'))
self.titleList.addItem(QtGui.QListWidgetItem('Title 2'))
self.titleList.itemDoubleClicked.connect(self.onClicked)
def onClicked(self, item):
## Just test values
title = item.text()
summary = "Here you will put the summary of {}. ".format(title)*50
## Pass the values as a list in the signal. You can pass as much values
## as you want, remember that all of them have to be inside one list
self.TitleClicked.emit([title, summary])
class WidgetTwo(QtGui.QWidget):
def __init__(self):
QtGui.QWidget.__init__(self)
self.layout = QtGui.QVBoxLayout()
self.setLayout(self.layout)
self.label2 = QtGui.QLabel('Here we show results?:')
self.text_box = QtGui.QTextBrowser()
self.layout.addWidget(self.label2)
self.layout.addWidget(self.text_box)
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
window = MyApp()
window.show()
sys.exit(app.exec_())
Again, there are comments inside the code to help you understand what I did.
Here is how it looks:
If you pass the mouse between the two widgets you will see the mouse icon will change, with that you can readjust on the run the size of both widgets.
Final Words
This is another approach, more "interactive" and more esthetic than my previous answer. As you said, using a QSplitter works too.

Problems
The way you are building your GUI is, in my opinion, messy and it may lead to errors. I suggest the use of Layouts for a more organized GUI.
The other problem is that each widget is an independent class so if you want to connect an action in one widget to do something in the other widget through the Main Window, you must use Signals.
Edit : Another suggestion, use other name for the close function instead of exit and try using self.close() instead of QCoreApplication.instance().quit()
Solution
Trying to emulate what you want to do I made this GUI:
import sys
from PyQt5 import QtGui, QtCore
class MyWindow(QtGui.QMainWindow):
def __init__(self):
QtGui.QMainWindow.__init__(self)
## Generate the structure parts of the MainWindow
self.central_widget = QtGui.QWidget() # A QWidget to work as Central Widget
self.layout1 = QtGui.QVBoxLayout() # Vertical Layout
self.layout2 = QtGui.QHBoxLayout() # Horizontal Layout
self.widget_one = WidgetOne()
self.widget_two = WidgetTwo()
self.exitBtn = QtGui.QPushButton('Exit')
## Build the structure
# Insert a QWidget as a central widget for the MainWindow
self.setCentralWidget(self.central_widget)
# Add a principal layout for the widgets/layouts you want to add
self.central_widget.setLayout(self.layout1)
# Add widgets/layuts, as many as you want, remember they are in a Vertical
# layout: they will be added one below of the other
self.layout1.addLayout(self.layout2)
self.layout1.addWidget(self.exitBtn)
# Here we add the widgets to the horizontal layout: one next to the other
self.layout2.addWidget(self.widget_one)
self.layout2.addWidget(self.widget_two)
## Connect the signal
self.widget_one.TitleClicked.connect(self.dob_click)
def dob_click(self, feed):
## Change the properties of the elements in the second widget
self.widget_two.title.setText('Title : '+feed[0])
self.widget_two.summary.setText('Summary : '+feed[1])
## Build your widgets same as the Main Window, with the excepton that here you don't
## need a central widget, because it is already a widget.
class WidgetOne(QtGui.QWidget):
TitleClicked = QtCore.pyqtSignal([list]) # Signal Created
def __init__(self):
QtGui.QWidget.__init__(self)
##
self.layout = QtGui.QVBoxLayout() # Vertical Layout
self.setLayout(self.layout)
self.titleList = QtGui.QListWidget()
self.label = QtGui.QLabel('Here is my list:')
self.layout.addWidget(self.label)
self.layout.addWidget(self.titleList)
self.titleList.addItem(QtGui.QListWidgetItem('Title 1'))
self.titleList.addItem(QtGui.QListWidgetItem('Title 2'))
self.titleList.itemDoubleClicked.connect(self.onClicked)
def onClicked(self, item):
## Just test parameters and signal emited
self.TitleClicked.emit([item.text(), item.text()+item.text()])
class WidgetTwo(QtGui.QWidget):
def __init__(self):
QtGui.QWidget.__init__(self)
self.layout = QtGui.QVBoxLayout()
self.setLayout(self.layout)
self.title = QtGui.QLabel('Title : ---')
self.summary = QtGui.QLabel('Summary : ---')
self.link = QtGui.QLabel('Link : ---')
self.layout.addWidget(self.title)
self.layout.addWidget(self.summary)
self.layout.addWidget(self.link)
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
window = MyWindow()
window.show()
sys.exit(app.exec_())
Inside the code, there are comments to help you understand why I did to build an organized GUI. There is also an example of a Signal being used to connect the action of itemDoubleClicked from the first widget to the second one. Here is how the MainWindow looks:
It is not very clear how the layouts work just from seeing the result, so I did a little paint over to a better understanding:
The blue box is the vertical layout (QVBoxLayout) and the red one is the horizontal layout (QHBoxLayout). Inside the blue layout, are located the red layout (above) and the exit button (below); and inside the red layout, are located the widget_1 (left) and the widget_2 (right).
Other Solution
An "easier" solution will be building the widgets inside the MainWindow instead of creating separate classes. With this you will avoid the use of signals, but the code will become a little more confusing because all the code will be cramped in one class.

How to get a PyQt5 QPushButton to do different commands on different button clicks

I wish to have the QPushButton do different things on different clicks. One the first click it should execute one command and on the next click, it should execute the other command. I've tried to make a program to do it but it only executes one command, not the other
my code I:
import PyQt5.QtWidgets as pyqt
import sys
ongoing = False
class Stuff(pyqt.QWidget):
def __init__(self):
super().__init__()
self.windows()
def windows(self):
w = pyqt.QWidget()
layout = pyqt.QGridLayout()
self.setLayout(layout)
button = pyqt.QPushButton('click me', w)
layout.addWidget(button)
if not ongoing:
button.clicked.connect(click_one)
else:
button.clicked.connect(click_two)
self.show()
w.show()
def click_one():
global ongoing
print('one')
ongoing = not ongoing
def click_two():
global ongoing
print('two')
ongoing = not ongoing
if __name__ == '__main__':
app = pyqt.QApplication(sys.argv)
x = Stuff()
app.exec_()
What should I do to fix this?

Since the value of ongoing is False when the class is initialized, the button's clicked signal gets connected to click_one(). Connect the button to an initial slot and then call the desired function based on the value of ongoing.
class Stuff(pyqt.QWidget):
def __init__(self):
super().__init__()
self.windows()
def windows(self):
w = pyqt.QWidget()
layout = pyqt.QGridLayout()
self.setLayout(layout)
button = pyqt.QPushButton('click me', w)
layout.addWidget(button)
button.clicked.connect(on_click)
self.show()
w.show()
def on_click():
global ongoing
if not ongoing:
click_one()
else:
click_two()
I suggest rewriting the code with the functions and ongoing variable belonging to the class. The QWidget assigned to variable w seems redundant because the QPushButton is then added to the layout of the class, so its parent gets changed anyways.
class Stuff(pyqt.QWidget):
def __init__(self):
super().__init__()
self.ongoing = False
self.windows()
def windows(self):
layout = pyqt.QGridLayout(self)
button = pyqt.QPushButton('click me')
layout.addWidget(button)
button.clicked.connect(self.on_click)
self.show()
def on_click(self):
self.click_one() if not self.ongoing else self.click_two()
self.ongoing = not self.ongoing
def click_one(self):
print('one')
def click_two(self):
print('two')
Also you might be interested in using a checkable button.

How can I add a submit, output and input box using PyQt4?

I never tried creating a GUI with a language other than Java(kinda left it aside not long ago)
and started using Python.
made a simple program that calculates Pi to a certain digit as the user wishes.
Now, I created a window with PyQt4, made a button and got everything in place.
How can I add a input box so that the user could enter a number into it, make the button "Enter" the information and at the end of all that output it to the window instead of the terminal?
That's what I've got for now:
import sys
from PyQt4 import QtGui
from PyQt4 import QtCore
from decimal import *
class Window(QtGui.QMainWindow):
def __init__(self):
super(Window, self).__init__()
self.setGeometry(50, 50, 800, 600)
self.setWindowTitle("Pi's Nth Digit")
self.setWindowIcon(QtGui.QIcon('icon.jpg'))
self.buttons()
def buttons(self):
btn = QtGui.QPushButton("Quit",self)
btn1 = QtGui.QPushButton("Get Pi",self)
btn.clicked.connect(QtCore.QCoreApplication.instance().quit)
btn1.clicked.connect(self.getpi())
btn1.resize(btn1.sizeHint())
btn.resize(btn.sizeHint())
btn1.move(350,500)
btn.move(450,500)
self.show()
def start():
app = QtGui.QApplication(sys.argv)
GUI = Window()
sys.exit(app.exec_())
start()
don't mind the getpi function.
Thanks! :)

You would want to use a QLineEdit or a QSpinBox for a number. If you want multiple things in a widget you would use a layout. A QMainWindow typically has one central widget and toolbars and dock widgets.
class Window(QtGui.QMainWindow):
def __init__(self):
super().__init__()
self.container = QtGui.QWidget()
self.setCentralWidget(self.container)
self.container_lay = QtGui.QVBoxLayout()
self.container.setLayout(self.container_lay)
# Input
self.le = QtGui.QLineEdit()
self.container_lay.addWidget(self.le)
# enter button
self.enter_btn = QtGui.QPushButton("Enter")
self.container_lay.addWidget(self.enter_btn)
self.enter_btn.clicked.connect(self.run) # No '()' on run you want to reference the method.
# display
self.container_lay.addWidget(QtGui.QLabel("Answer:"))
self.ans = QtGui.QLabel()
self.container_lay.addWidget(self.ans)
def run(self):
precision = self.le.text()
pi = str(round(math.pi, precision)) # probably different formatting
self.ans.setText(pi)
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
window = Window()
window.show()
sys.exit(app.exec_())

You have almost everything, just add a QLineEdit to get the input and a QLabel where to show the result (with QLabel.setText).