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Access A Variable from another class in PyQt5

In PyQt5, I've wrote a GUI. Basically, when a button is pressed, it open a new window, where choose an item from a list. What I want is that after you close the new window, the item you chose appears as text on the first window. It's a hard to explain.
This is the code:
import sys
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QFont
from PyQt5 import QtWidgets
from PyQt5 import QtCore
from PyQt5 import QtGui
class Add(QtWidgets.QMainWindow):
def __init__(self):
super(Add, self).__init__()
#Set The UI
self.initUI()
#Set The GUI Position And Size
self.setGeometry(1050, 500, 400, 50)
#Set The GUI Title
self.setWindowTitle("Add")
def initUI(self):
Central = QtWidgets.QWidget(self)
self.setCentralWidget(Central)
self.deckButton = QtWidgets.QPushButton(self)
self.deckButton.setText("Choose")
self.deckButton.clicked.connect(self.open_deck_browser)
hbox = QtWidgets.QHBoxLayout()
hbox.addWidget(self.deckButton, 1)
Central.setLayout(hbox)
def open_deck_browser(self):
self.w = SetDeck()
self.w.show()
class SetDeck(QtWidgets.QMainWindow):
def __init__(self):
super(SetDeck, self).__init__()
#Set The UI
self.initUI()
#Set The GUI Position And Size
self.setGeometry(200, 200, 800, 640)
#Set The GUI Title
self.setWindowTitle("Choose Deck")
def initUI(self):
widAddToDeckWindow = QtWidgets.QWidget(self)
self.setCentralWidget(widAddToDeckWindow)
#Create The List Widget
self.deckList = QtWidgets.QListWidget()
self.deckList.insertItem(0, "Hello")
self.deckList.insertItem(1, "Hi")
self.deckList.insertItem(2, "Hello There")
self.deckList.item(0).setSelected(True)
self.deckList.itemSelectionChanged.connect(self.show_List)
print([x.row() for x in self.deckList.selectedIndexes()])
#Create The Select Deck Button
self.selectDeck = QtWidgets.QPushButton(self)
self.selectDeck.setText("Choose")
hboxCreateBottomButtons = QtWidgets.QHBoxLayout()
hboxCreateBottomButtons.addStretch()
hboxCreateBottomButtons.addWidget(self.selectDeck)
#Create The Main VBox
vboxMain = QtWidgets.QVBoxLayout()
vboxMain.addWidget(self.deckList)
vboxMain.addLayout(hboxCreateBottomButtons)
widAddToDeckWindow.setLayout(vboxMain)
def show_List(self):
print(repr(self.deckList.selectedItems()[0].text()))
def window():
app = QtWidgets.QApplication(sys.argv)
win = Add()
win.show()
sys.exit(app.exec_())
window()
I've tried using global variables, but it didn't work.

First of all, I recommend you improve your style when naming variables as they make reading easier, for example that the class name are nouns and not a verb.
Getting to the bottom of the problem, never use (or try to use) global variables as they cause silent bugs if there is a better option and you don't understand how it works. In the case that you want a window where you ask the user to provide information on how to select an option that will then be used in the main window then it is advisable to use a QDialog. In the following example, this is done and the "Choose" button is linked to the accept slot so that it closes the window, and that information can be used to know that the "x" button of the window was not closed. Also I have created a property that has the selected text.
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
class MainWindow(QtWidgets.QMainWindow):
def __init__(self):
super(MainWindow, self).__init__()
self.initUI()
self.setGeometry(1050, 500, 400, 50)
self.setWindowTitle("Add")
def initUI(self):
central = QtWidgets.QWidget(self)
self.setCentralWidget(central)
self.deckButton = QtWidgets.QPushButton()
self.deckButton.setText("Choose")
self.deckButton.clicked.connect(self.open_deck_browser)
box = QtWidgets.QVBoxLayout(central)
box.addWidget(self.deckButton)
self.label = QtWidgets.QLabel()
box.addWidget(self.label)
self.label.hide()
def open_deck_browser(self):
dialog = DeckDialog()
if dialog.exec_() == QtWidgets.QDialog.Accepted:
self.label.show()
self.label.setText(dialog.selected_text)
class DeckDialog(QtWidgets.QDialog):
def __init__(self):
super(DeckDialog, self).__init__()
self.initUI()
self.setGeometry(200, 200, 800, 640)
self.setWindowTitle("Choose Deck")
def initUI(self):
self.deckList = QtWidgets.QListWidget()
self.deckList.insertItem(0, "Hello")
self.deckList.insertItem(1, "Hi")
self.deckList.insertItem(2, "Hello There")
self.deckList.item(0).setSelected(True)
self.selectDeck = QtWidgets.QPushButton(self)
self.selectDeck.setText("Choose")
hboxCreateBottomButtons = QtWidgets.QHBoxLayout()
hboxCreateBottomButtons.addStretch()
hboxCreateBottomButtons.addWidget(self.selectDeck)
vboxMain = QtWidgets.QVBoxLayout(self)
vboxMain.addWidget(self.deckList)
vboxMain.addLayout(hboxCreateBottomButtons)
self.selectDeck.clicked.connect(self.accept)
#property
def selected_text(self):
items = self.deckList.selectedItems()
if items:
return items[0].text()
return ""
def main():
app = QtWidgets.QApplication(sys.argv)
win = MainWindow()
win.show()
sys.exit(app.exec_())
if __name__ == "__main__":
main()

How do I set layout's fixed height in PyQt5?

I am trying to set a fixed height for QHBoxLayout. To elaborate more on that, I need to set a specific height for my Horizontal layout. However, I cannot find the proper way to do so. What should I do to make this happen?
hbox1 = QHBoxLayout()

As noted by #ekhumuro in QHBoxLayout you can not set the fixed height, you must do that to the widget where it will be contained as I show below:
import random
from PyQt5 import QtCore, QtGui, QtWidgets
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super(Widget, self).__init__(parent)
self.setFixedHeight(300)
lay = QtWidgets.QHBoxLayout(self)
for letter in "ABCDEFG":
label = QtWidgets.QLabel(letter, alignment=QtCore.Qt.AlignCenter)
color = QtGui.QColor(*[random.randint(0, 255) for _ in range(3)])
label.setStyleSheet("background-color: {}".format(color.name()))
lay.addWidget(label)
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())

Increase Height of QPushButton in PyQT

I have 2 QPushButton in the app window: btn1 needs to be 5x the height of btn2.
Problem: Tried setting the row span of self.btn1 to 5 using layout.addWidget but the height remains unchanged. did I miss out on a setting?
import sys
from PyQt4 import QtGui, QtCore
class MainWindow(QtGui.QMainWindow):
def __init__(self):
super(MainWindow, self).__init__()
self.initUI()
def initUI(self):
layout = QtGui.QGridLayout()
self.btn1 = QtGui.QPushButton('Hello')
self.btn2 = QtGui.QPushButton('World')
layout.addWidget(self.btn1, 1, 1, 5, 1)
layout.addWidget(self.btn2, 6, 1, 1, 1)
centralWidget = QtGui.QWidget()
centralWidget.setLayout(layout)
self.setCentralWidget(centralWidget)
def main():
app = QtGui.QApplication(sys.argv)
mainWindow = MainWindow()
mainWindow.show()
sys.exit(app.exec_())
if __name__ == '__main__':
main()

You'll need to change the buttons' size policy:
self.btn1.setSizePolicy(
QtGui.QSizePolicy.Preferred,
QtGui.QSizePolicy.Expanding)
self.btn2.setSizePolicy(
QtGui.QSizePolicy.Preferred,
QtGui.QSizePolicy.Preferred)
From Qt doc, by default:
Button-like widgets set the size policy to specify that they may
stretch horizontally, but are fixed vertically.
i.e. The default size policy of QPushButton is Minimum horizontally, and Fixed vertically.
In addition, a simpler way to achieve what you want in the example is to use a QVBoxLayout, and set the stretch factor when calling addWidget(). i.e.
def initUI(self):
layout = QtGui.QVBoxLayout()
self.btn1 = QtGui.QPushButton('Hello')
self.btn2 = QtGui.QPushButton('World')
self.btn1.setSizePolicy(
QtGui.QSizePolicy.Preferred,
QtGui.QSizePolicy.Expanding)
self.btn2.setSizePolicy(
QtGui.QSizePolicy.Preferred,
QtGui.QSizePolicy.Preferred)
layout.addWidget(self.btn1, 5)
layout.addWidget(self.btn2, 1)
centralWidget = QtGui.QWidget()
centralWidget.setLayout(layout)
self.setCentralWidget(centralWidget)

PySide QGraphicsView size

I have 2 issues with QGraphicsView.
I can't get the size of the QGraphicsView object. All methods I'm using is giving me values I wouldn't expect.
If I print out the mouse's position on the area's lower-right corner (scrollbars included), I get a random 400 value. After setting sceneRect to 500 I was expecting to get that back.
from PySide import QtGui, QtCore
class View(QtGui.QGraphicsView):
def __init__(self, parent = None):
super(View, self).__init__(parent)
self.setScene( QtGui.QGraphicsScene(self) )
self.setSceneRect( 0, 0, 500, 500 )
print self.viewport().width() # outputs 96
print self.width() # outputs 100
print self.rect() # outputs QRect(0, 0, 100, 30)
print self.size() # outputs QSize(100, 30)
def mouseMoveEvent(self, event):
print event.pos().toTuple() # prints (413, 423) at lower-right corner
class MainWindow(QtGui.QWidget):
def __init__(self):
super(MainWindow, self).__init__()
self.resize(500, 500)
self.view = View(self)
hLayout = QtGui.QHBoxLayout()
hLayout.addWidget(self.view)
buttonsLayout = QtGui.QVBoxLayout()
buttonsLayout.setSpacing(0)
for i in range(10):
newButton = QtGui.QPushButton()
buttonsLayout.addWidget(newButton)
hLayout.addLayout(buttonsLayout)
self.tempButton = QtGui.QPushButton()
mainLayout = QtGui.QVBoxLayout()
mainLayout.addLayout(hLayout)
mainLayout.addWidget(self.tempButton)
self.setLayout(mainLayout)
def run(self):
self.show()
win = MainWindow()
win.run()
Thank you!

Regarding your first issue, I believe you are not getting the sizes you are expecting for two reasons:
You are not explicitly setting the size of the QGraphicsView widget to 500, but the QGraphicsScene instead.
You are fetching the sizes too early in the construction of your application, before the layout of the MainWindow has been properly painted.
Regarding your second issue, depending of what is desired, it is possible to use the method mapFromScene to get the position of the mouse event in regard to the QGraphicsScene instead of the QGraphicsView widget.
More specifically, this can be achieve in your code by:
Setting the size of the QGraphicsView widget with setFixedSize ;
Moving the "size-fetching" calls in the run method, after the MainWindow has been painted ;
Adding a mapToScene transformation on the mouseMoveEvent coordinate.
Below is the code that was modified accordingly to the points listed above:
from PySide import QtGui, QtCore
import sys
class View(QtGui.QGraphicsView):
def __init__(self, parent = None):
super(View, self).__init__(parent)
self.setScene(QtGui.QGraphicsScene(self) )
self.setSceneRect( 0, 0, 1000, 1000 )
self.setFixedSize(500, 500)
def mouseMoveEvent(self, event):
print
print self.mapToScene(event.pos()).toTuple()
# prints (1000, 1000) at lower-right corner
print event.pos().toTuple()
# prints (500, 500) at lower-right corner
class MainWindow(QtGui.QWidget):
def __init__(self):
super(MainWindow, self).__init__()
self.view = View(self)
hLayout = QtGui.QHBoxLayout()
hLayout.addWidget(self.view)
buttonsLayout = QtGui.QVBoxLayout()
buttonsLayout.setSpacing(0)
for i in range(10):
newButton = QtGui.QPushButton()
buttonsLayout.addWidget(newButton)
hLayout.addLayout(buttonsLayout)
self.tempButton = QtGui.QPushButton()
mainLayout = QtGui.QVBoxLayout()
mainLayout.addLayout(hLayout)
mainLayout.addWidget(self.tempButton)
self.setLayout(mainLayout)
def run(self):
self.show()
print
print self.view.viewport().width() # outputs 485
print self.view.width() # outputs 500
print self.view.rect() # outputs QRect(0, 0, 500, 500)
print self.view.size() # outputs QSize(500, 500)
print self.view.sceneRect() #outputs QRect(0, 0, 1000, 1000)
if __name__ == '__main__':
app = QtGui.QApplication(sys.argv)
win = MainWindow()
win.run()
sys.exit(app.exec_())
With the code above, the value returned for the size of QGraphicView is 500x500, while it is 1000x1000 for the QGraphicsScene, as expected.

How to resize the main window again after setFixedSize()?

I would like to resize the MainWindow (QMainWindow) after I make some widgets unvisible and vice versa. And I want to block the window resize.
def hideAndShowWidget(self):
self.widgetObject.setVisible(not self.widgetObject.isVisible() )
# change main window size here
# ...
self.setFixedSize(self.width(), self.height())
My problem is, that i can not change the window size after i call setFixedSize() first time. I read here that I must use QWIDGETSIZE_MAX() to remove constraints, but I don't know how can I use it, I get the error:
NameError: name 'QWIDGETSIZE_MAX' is not defined

I think you have the mechanism more or less right. You just have to make sure the height calculation is done correctly (i.e. before the visibility of the widget changes).
The following example works correctly for me (only tested on Linux, though):
from PySide import QtGui
class Window(QtGui.QWidget):
def __init__(self):
super(Window, self).__init__()
self.widgetObject = QtGui.QTextEdit(self)
self.button = QtGui.QPushButton('Hide Widget', self)
self.button.clicked.connect(self.hideAndShowWidget)
layout = QtGui.QVBoxLayout(self)
layout.addWidget(self.button)
layout.addWidget(self.widgetObject)
self.setFixedSize(300, 200)
def hideAndShowWidget(self):
height = self.height()
if self.widgetObject.isVisible():
height -= self.widgetObject.height()
self.widgetObject.setVisible(False)
self.button.setText('Show Widget')
else:
height += self.widgetObject.height()
self.widgetObject.setVisible(True)
self.button.setText('Hide Widget')
self.setFixedSize(self.width(), height)
if __name__ == '__main__':
import sys
app = QtGui.QApplication(sys.argv)
window = Window()
window.show()
sys.exit(app.exec_())

Use the sizeHint(). It contains the size the widget would like to have. Set the fixed size exactly to the size hint.
Working example:
from PySide import QtGui
class Window(QtGui.QMainWindow):
def __init__(self):
super().__init__()
self.setFixedSize(400, 300)
widget = QtGui.QWidget()
layout = QtGui.QVBoxLayout(widget)
button = QtGui.QPushButton('Toggle visibility')
button.clicked.connect(self.hideAndShowWidget)
layout.addWidget(button)
self.widgetObject = QtGui.QLabel('Test')
layout.addWidget(self.widgetObject)
self.setCentralWidget(widget)
def hideAndShowWidget(self):
self.widgetObject.setVisible(not self.widgetObject.isVisible() )
# change main window size
self.setFixedSize(self.sizeHint())
app = QtGui.QApplication([])
w = Window()
w.show()
app.exec_()