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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()

Why my program is closing when I am using Slider in pyqt5?

Why my program is closing when I am using Slider in pyqt5? It starts normal but after using Slider it close. I have to change size of circle in first window by using Slider from second window. This is my full code, beacuse I don't know what could be wrong.
from PyQt5.QtWidgets import *
from PyQt5.QtGui import QPainter, QBrush, QPen
from PyQt5.QtCore import Qt
import sys
class ThirdWindow(QWidget):
def __init__(self):
super().__init__()
hbox = QHBoxLayout()
sld = QSlider(Qt.Horizontal, self)
sld.setRange(0, 100)
sld.setFocusPolicy(Qt.NoFocus)
sld.setPageStep(5)
sld.valueChanged.connect(self.updateLabel)
self.label = QLabel('0', self)
self.label.setAlignment(Qt.AlignCenter | Qt.AlignVCenter)
self.label.setMinimumWidth(80)
hbox.addWidget(sld)
hbox.addSpacing(15)
hbox.addWidget(self.label)
self.setLayout(hbox)
self.setGeometry(600, 60, 500, 500)
self.setWindowTitle('QSlider')
self.show()
def updateLabel(self, value):
self.label.setText(str(value))
self.parentWidget().radius = value
self.parentWidget().repaint()
class Window(QMainWindow):
def __init__(self):
QMainWindow.__init__(self)
self.setWindowTitle("Dialogi")
self.w = ThirdWindow()
actionFile = self.menuBar().addMenu("Dialog")
action = actionFile.addAction("Zmień tło")
action1 = actionFile.addAction("Zmień grubość koła")
action1.triggered.connect(self.w.show)
self.setGeometry(100, 60, 300, 300)
self.setStyleSheet("background-color: Green")
self.radius = 100 # add a variable radius to keep track of the circle radius
def paintEvent(self, event):
painter = QPainter(self)
painter.setPen(QPen(Qt.gray, 8, Qt.SolidLine))
# change function to include radius
painter.drawEllipse(100, 100, self.radius, self.radius)
app = QApplication(sys.argv)
screen = Window()
screen.show()
sys.exit(app.exec_())

parentWidget allows access to a widget declared as parent for Qt.
Creating an object using self.w = ... doesn't make that object a child of the parent (self), you are only creating a reference (w) to it.
If you run your program in a terminal/prompt you'll clearly see the following traceback:
Exception "unhandled AttributeError"
'NoneType' object has no attribute 'radius'
The NoneType refers to the result of parentWidget(), and since no parent has been actually set, it returns None.
While you could use parentWidget if you correctly set the parent for that widget (by adding the parent to the widget constructor, or using setParent()), considering the structure of your program it wouldn't be a good choice, and it's usually better to avoid changes to a "parent" object directly from the "child": the signal/slot mechanism of Qt is exactly intended for the modularity of Object Oriented Programming, as a child should not really "care" about its parent.
The solution is to connect to the slider from the "parent", and update it from there.
class ThirdWindow(QWidget):
def __init__(self):
# ...
# make the slider an *instance member*, so that we can easily access it
# from outside
self.slider = QSlider(Qt.Horizontal, self)
# ...
class Window(QMainWindow):
def __init__(self):
# ...
self.w.slider.valueChanged.connect(self.updateLabel)
def updateLabel(self, value):
self.radius = value
self.update()
You obviously need to remove the valueChanged connection in the ThirdWindow class, as you don't need it anymore.
Also note that you rarely need repaint(), and update() should be preferred instead.

PyQt5: Slot in separate file not being called

I currently have a basic GUI right now with each page in its own file. I can navigate to and from each page with no problem, but I'm having difficulty simply passing a search query to another Widget. Here's where I setup the connections in the main file:
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
import sys
import search
import watching
import helpinfo
import results
class MainWindow(QMainWindow):
def __init__(self, parent=None):
'''
Constructor
'''
QMainWindow.__init__(self, parent)
self.centralWidget = QStackedWidget()
self.setCentralWidget(self.centralWidget)
self.startScreen = Start(self)
self.searchScreen = search.Search(self)
self.watchingScreen = watching.Watching(self)
self.helpInfoScreen = helpinfo.HelpInfo(self)
self.resultsScreen = results.Results(self)
self.centralWidget.addWidget(self.startScreen)
self.centralWidget.addWidget(self.searchScreen)
self.centralWidget.addWidget(self.watchingScreen)
self.centralWidget.addWidget(self.helpInfoScreen)
self.centralWidget.addWidget(self.resultsScreen)
self.centralWidget.setCurrentWidget(self.startScreen)
self.startScreen.searchClicked.connect(lambda: self.centralWidget.setCurrentWidget(self.searchScreen))
self.startScreen.watchingClicked.connect(lambda: self.centralWidget.setCurrentWidget(self.watchingScreen))
self.startScreen.helpInfoClicked.connect(lambda: self.centralWidget.setCurrentWidget(self.helpInfoScreen))
self.searchScreen.searchSubmitted.connect(lambda: self.centralWidget.setCurrentWidget(self.resultsScreen))
self.searchScreen.passQuery.connect(lambda: self.resultsScreen.grabSearch) #This is the problem line
self.searchScreen.clicked.connect(lambda: self.centralWidget.setCurrentWidget(self.startScreen))
self.watchingScreen.clicked.connect(lambda: self.centralWidget.setCurrentWidget(self.startScreen))
self.helpInfoScreen.clicked.connect(lambda: self.centralWidget.setCurrentWidget(self.startScreen))
self.resultsScreen.clicked.connect(lambda: self.centralWidget.setCurrentWidget(self.startScreen))
Here's the search file:
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
import sys
class Search(QWidget):
clicked = pyqtSignal()
searchSubmitted = pyqtSignal()
passQuery = pyqtSignal(str)
def __init__(self, parent=None):
super(Search, self).__init__(parent)
logo = QLabel(self)
pixmap = QPixmap('res/logo.png')
logo.setPixmap(pixmap)
logo.setSizePolicy(QSizePolicy.Preferred, QSizePolicy.Preferred)
logo.setAlignment(Qt.AlignCenter)
self.textbox = QLineEdit(self)
label = QLabel(text="This is the search page.")
label.setAlignment(Qt.AlignCenter)
button = QPushButton(text='Submit')
button.clicked.connect(lambda: self.submitSearch())
button2 = QPushButton(text='Go back.')
button2.clicked.connect(self.clicked.emit)
layout = QVBoxLayout()
layout.addWidget(logo)
layout.addWidget(label)
layout.addWidget(self.textbox)
layout.addWidget(button)
layout.addWidget(button2)
layout.setAlignment(Qt.AlignTop)
self.setLayout(layout)
def submitSearch(self):
self.searchSubmitted.emit()
self.passQuery.emit(self.textbox.text())
And here is the results file:
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
class Results(QWidget):
clicked = pyqtSignal()
def __init__(self, parent=None):
super(Results, self).__init__(parent)
# Create Logo
logo = QLabel(self)
pixmap = QPixmap('res/logo.png')
logo.setPixmap(pixmap)
logo.setSizePolicy(QSizePolicy.Preferred, QSizePolicy.Preferred)
logo.setAlignment(Qt.AlignCenter)
# Create page contents
label = QLabel(text="This is the results page. If you see this, it's still broken.")
label.setAlignment(Qt.AlignCenter)
button = QPushButton(text='Add to watching.')
button2 = QPushButton(text='Go back.')
button2.clicked.connect(self.clicked.emit)
# Set up layout
layout = QVBoxLayout()
layout.addWidget(logo)
layout.addWidget(label)
layout.addWidget(button)
layout.addWidget(button2)
layout.setAlignment(Qt.AlignTop)
self.setLayout(layout)
#pyqtSlot(str)
def grabSearch(self, str):
print(str)
self.label.setText(str)
The way I understand it, what I have right now should be working. When the user submits some text on the search page, it calls the submitSearch() function. That function emits two signals: the first, searchSubmitted, changes the screen to the results screen (this works as intended). The second, passQuery, should be passing the contents of the textbox to the connected function grabSearch() in the results file. However, the passQuery never seems to be caught by the results page despite being connected. I've verified with print statements that it is being emitted, but that's it.
What am I missing here?

Your code has the following errors:
If you are going to use a lambda to make the connection you must invoke the function with the arguments.
self.searchScreen.passQuery.connect(lambda text: self.resultsScreen.grabSearch(text))
But it is better to use the direct connection since the signatures are the same:
self.searchScreen.passQuery.connect(self.resultsScreen.grabSearch)
Another error is that the results.py label must be a member of the class:
self.label = QLabel(text="This is the results page. If you see this, it's still broken.") # <--
self.label.setAlignment(Qt.AlignCenter) # <--
# ..
# Set up layout
layout = QVBoxLayout()
layout.addWidget(logo)
layout.addWidget(self.label) # <--
And finally do not use reserved words like str, change to:
#pyqtSlot(str)
def grabSearch(self, text):
self.label.setText(text)

PyQt5 - How to add a scrollbar to a QMessageBox

I have a list which is generated based on user-input.
I am trying to display this list in a QMessageBox. But, I have no way of knowing the length of this list. The list could be long.
Thus, I need to add a scrollbar to the QMessageBox.
Interestingly, I looked everywhere, but I haven’t found any solutions for this.
Below is, what I hope to be a “Minimal, Complete and Verifiable Example”, of course without the user input; I just created a list as an example.
I appreciate any advice.
import sys
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
class W(QWidget):
def __init__(self):
super().__init__()
self.initUi()
def initUi(self):
self.btn = QPushButton('Show Message', self)
self.btn.setGeometry(10, 10, 100, 100)
self.btn.clicked.connect(self.buttonClicked)
self.lst = list(range(2000))
self.show()
def buttonClicked(self):
result = QMessageBox(self)
result.setText('%s' % self.lst)
result.exec_()
if __name__ == "__main__":
app = QApplication(sys.argv)
gui = W()
sys.exit(app.exec_())

You can not add a scrollbar directly since the widget in charge of displaying the text is a QLabel. The solution is to add a QScrollArea. The size may be inadequate so a stylesheet has to be used to set minimum values.
class ScrollMessageBox(QMessageBox):
def __init__(self, l, *args, **kwargs):
QMessageBox.__init__(self, *args, **kwargs)
scroll = QScrollArea(self)
scroll.setWidgetResizable(True)
self.content = QWidget()
scroll.setWidget(self.content)
lay = QVBoxLayout(self.content)
for item in l:
lay.addWidget(QLabel(item, self))
self.layout().addWidget(scroll, 0, 0, 1, self.layout().columnCount())
self.setStyleSheet("QScrollArea{min-width:300 px; min-height: 400px}")
class W(QWidget):
def __init__(self):
super().__init__()
self.btn = QPushButton('Show Message', self)
self.btn.setGeometry(10, 10, 100, 100)
self.btn.clicked.connect(self.buttonClicked)
self.lst = [str(i) for i in range(2000)]
self.show()
def buttonClicked(self):
result = ScrollMessageBox(self.lst, None)
result.exec_()
if __name__ == "__main__":
app = QApplication(sys.argv)
gui = W()
sys.exit(app.exec_())
Output:

Here is another way to override the widgets behavior.
You can get references to the children of the widget by using 'children()'.
Then you can manipulate them like any other widget.
Here we add a QScrollArea and QLabel to the original widget's QGridLayout. We get the text from the original widget's label and copy it to our new label, finally we clear the text from the original label so it is not shown (because it is beside our new label).
Our new label is scrollable. We must set the minimum size of the scrollArea or it will be hard to read.
import sys
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
class ScrollMessageBox(QMessageBox):
def __init__(self, *args, **kwargs):
QMessageBox.__init__(self, *args, **kwargs)
chldn = self.children()
scrll = QScrollArea(self)
scrll.setWidgetResizable(True)
grd = self.findChild(QGridLayout)
lbl = QLabel(chldn[1].text(), self)
lbl.setWordWrap(True)
scrll.setWidget(lbl)
scrll.setMinimumSize (400,200)
grd.addWidget(scrll,0,1)
chldn[1].setText('')
self.exec_()
class W(QWidget):
def __init__(self):
super(W,self).__init__()
self.btn = QPushButton('Show Message', self)
self.btn.setGeometry(10, 10, 100, 100)
self.btn.clicked.connect(self.buttonClicked)
self.message = ("""We have encountered an error.
The following information may be useful in troubleshooting:
1
2
3
4
5
6
7
8
9
10
Here is the bottom.
""")
self.show()
def buttonClicked(self):
result = ScrollMessageBox(QMessageBox.Critical,"Error!",self.message)
if __name__ == "__main__":
app = QApplication(sys.argv)
gui = W()
sys.exit(app.exec_())

PYQT Accessing and changing dynamically added controls

I am a beginner with GUI's and PYQT. What I am trying to do is dynamically set up a grid of QComboBox's and QLineEdit's. From the QComboBox you can select a choice and from that choice, it will fill in the corresponding QLineEdit with some numbers. The problem I'm having is creating the link between the first QComboBox and the first QLineEdit box. I could make a function for each row but I would like to know a better way. I will post some sample code. Thank you for any help or advice that you might have.
import sys
from PyQt5.QtCore import QCoreApplication
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
class window(QMainWindow):
def __init__(self):
super(window, self).__init__()
self.setGeometry(50, 50, 700, 600)
self.home()
def home(self):
Test1Choices = ['Test1:','Choice1', 'Choice2', 'Choice3', 'Choice4','Choice5', 'Choice6', 'Choice7', 'Choice8', 'Choice9']
Test2Choices= ['Test2:','1','2','3','4','5','6','7','8','9','10','11','12','13','14','15']
for i in range(0,10):
Choice1ComboBox = QComboBox(self)
Choice1ComboBox.addItems(Test1Choices)
Choice1ComboBox.resize(150,25)
Choice1ComboBox.move(30,(150+(i*35)))
Choice1ComboBox.setCurrentIndex(2)
Choice2ComboBox = QComboBox(self)
Choice2ComboBox.setObjectName("Choice2ComboBox"+str(i))
Choice2ComboBox.addItems(Test2Choices)
Choice2ComboBox.resize(75,25)
Choice2ComboBox.move(200,(150+(i*35)))
Choice2ComboBox.setCurrentIndex(2)
Choice2ComboBox.activated[str].connect(self.doSomething)
numTextBox = QLineEdit(self)
numTextBox.setObjectName("numBox"+str(i))
numTextBox.move(325,(150+(i*35)))
numTextBox.resize(35,25)
result1TextBox = QLineEdit(self)
result1TextBox.setObjectName("result1Box"+str(i))
result1TextBox.move(400,(150+(i*35)))
result1TextBox.resize(100,25)
result1TextBox.setEnabled(0)
result2TextBox = QLineEdit(self)
result2TextBox.setObjectName("result2Box"+str(i))
result2TextBox.move(525,(150+(i*35)))
result2TextBox.resize(100,25)
result2TextBox.setEnabled(0)
self.show()
def doSomething(self):
numbers=['result1','result2','result3','result4','result5','result6','result7','result8','result9','result10','result11','result12','result13','result14','result15']
def run():
app = QApplication(sys.argv)
Gui = window()
sys.exit(app.exec_())
run()
To summarize I would like to bring in the index of the selected QComboBox. Then use that index number to reference the answer that is in the "numbers" array. Then print that result in the QLineEdit that is in the same row

We use sender() to get the object that emits the signal, then we look for the name of that object with setObjectName(), and we search the index, then we get the other objects with findChildren(), for example the output will be the union of the selected texts.
add name to Choice1ComboBox:
Choice1ComboBox.setObjectName("Choice1ComboBox"+str(i))
doSomething function:
def doSomething(self, _):
sender = self.sender()
l = sender.objectName().split("Choice1ComboBox")
if len(l) > 1:
number = l[1]
else:
number = sender.objectName().split("Choice2ComboBox")[1]
combo1 = self.findChildren(QComboBox, "Choice1ComboBox"+number)[0]
combo2 = self.findChildren(QComboBox, "Choice2ComboBox"+number)[0]
obj = self.findChildren(QLineEdit, "numBox"+number)[0]
obj.setText(combo1.currentText() + " " + combo2.currentText())
Complete code:
import sys
from PyQt5.QtCore import QCoreApplication
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
class window(QMainWindow):
def __init__(self):
super(window, self).__init__()
self.setGeometry(50, 50, 700, 600)
self.home()
def home(self):
Test1Choices = ['Test1:','Choice1', 'Choice2', 'Choice3', 'Choice4','Choice5', 'Choice6', 'Choice7', 'Choice8', 'Choice9']
Test2Choices= ['Test2:','1','2','3','4','5','6','7','8','9','10','11','12','13','14','15']
for i in range(0,10):
Choice1ComboBox = QComboBox(self)
Choice1ComboBox.setObjectName("Choice1ComboBox"+str(i))
Choice1ComboBox.addItems(Test1Choices)
Choice1ComboBox.resize(150,25)
Choice1ComboBox.move(30,(150+(i*35)))
Choice1ComboBox.setCurrentIndex(2)
Choice1ComboBox.activated[str].connect(self.doSomething)
Choice2ComboBox = QComboBox(self)
Choice2ComboBox.setObjectName("Choice2ComboBox"+str(i))
Choice2ComboBox.addItems(Test2Choices)
Choice2ComboBox.resize(75,25)
Choice2ComboBox.move(200,(150+(i*35)))
Choice2ComboBox.setCurrentIndex(2)
Choice2ComboBox.activated[str].connect(self.doSomething)
numTextBox = QLineEdit(self)
numTextBox.setObjectName("numBox"+str(i))
numTextBox.move(325,(150+(i*35)))
numTextBox.resize(35,25)
result1TextBox = QLineEdit(self)
result1TextBox.setObjectName("result1Box"+str(i))
result1TextBox.move(400,(150+(i*35)))
result1TextBox.resize(100,25)
result1TextBox.setEnabled(0)
result2TextBox = QLineEdit(self)
result2TextBox.setObjectName("result2Box"+str(i))
result2TextBox.move(525,(150+(i*35)))
result2TextBox.resize(100,25)
result2TextBox.setEnabled(0)
self.show()
def doSomething(self, _):
sender = self.sender()
l = sender.objectName().split("Choice1ComboBox")
if len(l) > 1:
number = l[1]
else:
number = sender.objectName().split("Choice2ComboBox")[1]
combo1 = self.findChildren(QComboBox, "Choice1ComboBox"+number)[0]
combo2 = self.findChildren(QComboBox, "Choice2ComboBox"+number)[0]
obj = self.findChildren(QLineEdit, "numBox"+number)[0]
obj.setText(combo1.currentText() + " " + combo2.currentText())
def run():
app = QApplication(sys.argv)
Gui = window()
sys.exit(app.exec_())
run()