Layout is changing when using QScrollArea in PyQt5

deleted412

Thanks for your help. Is it better practice to make separate classes for my QScrollAreas? Or can I include this code in my class of QMainWindow?

SGaist

I'd say it depends on what you are going to develop. For your current tests you can do everything in your QMainWindow.

deleted412

Thanks. For practice, I'm attempting to create a different QScrollArea in a separate class. How would I then attach this separate class to my QMainWindow?

SGaist

If you implement it in a separate Python file, the same way you do for other widgets, import and use.

deleted412

Okay, I understand. However, how would I accomplish this if I were to add these classes in the same Python file, i.e., in the same main() function as my QMainWindow?

For example, I would like to pass a variable from my QMainWindow into a separate QScrollArea class. However, I would like the QScrollArea to then be attached to my QMainWindow, which does not happen in my test:

from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
import sys


class FirstWindow(QMainWindow):
    def __init__(self):
        super(FirstWindow, self).__init__()

        self.setGeometry(500, 600, 600, 1000)

        self.first = First("Test String")


class First(QScrollArea):
    def __init__(self, label_text):
        super(First, self).__init__()

        self.setGeometry(100, 300, 400, 400)
        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
        self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setWidgetResizable(True)

        self.layout_1 = QVBoxLayout()

        self.scroll_widget1 = QWidget(self)
        self.scroll_widget1.setGeometry(100, 300, 398, 398)

        self.scroll_widget1.setLayout(self.layout_1)

        self.setWidget(self.scroll_widget1)


        for i in range(50):
            self.label = QLabel(self)
            self.label.setText(label_text)
            self.layout_1.addWidget(self.label)

        self.show()


def main():
    app = QApplication(sys.argv)
    win = FirstWindow()
    win.show()
    app.exec_()

main()

SGaist

Do not call show in your subclass constructor, it's not its role to say when to be shown.

I think you are over engineering things. A custom widget that you create should be used in the same manner as any provided by Qt.

deleted412

Thanks! So this example is acceptable/best practice when incorporating other widgets into my QMainWindow?

from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
import sys


class FirstWindow(QMainWindow):
    def __init__(self):
        super(FirstWindow, self).__init__()

        self.setGeometry(500, 600, 600, 1000)

        self.scroll = QScrollArea(self)
        self.scroll.setGeometry(100, 300, 400, 400)
        self.scroll.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
        self.scroll.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.scroll.setWidgetResizable(True)

        self.layout_1 = QVBoxLayout()

        self.scroll_widget1 = QWidget(self)
        self.scroll_widget1.setGeometry(100, 300, 398, 398)

        self.scroll_widget1.setLayout(self.layout_1)

        self.scroll.setWidget(self.scroll_widget1)

        for i in range(50):
            self.label = QLabel(self)
            self.label.setText("Test String")
            self.layout_1.addWidget(self.label)

def main():
    app = QApplication(sys.argv)
    win = FirstWindow()
    win.show()
    app.exec_()

main()

SGaist

You forgot to set your QScrollArea as central widget.

deleted412

Thanks for the reminder. Why would you say that this has to be the central widget? Suppose I add a title to the GUI, this would not be the central widget?

SGaist

Just because you are using a QMainWindow as base class of your main widget. Otherwise, you should put it in a layout in your main widget.