Creating a custom widget in PyQT5

Question

I would like to know how one can create a custom widget in pyqt. I've seen many different examples for C++, and a couple non descript examples for pyqt, but nothing that really explains how to do it and implement it. There is especially no examples that basically aren't just modified qt-designer output, and I'm writing my code from scratch so that's not very helpful.

So far, the best example I could find was basically just someone modifying qt-designer code and not really explaining what any of it was doing.

Could someone please show me an example of how to create a custom widget?

Edit: I'm attempting to create a widget with an embedded QStackedWidget, and buttons on the bottom to cycle the pages.

I also planned on having a seperate widget for each page, but considering I can't actually accomplish step one, I figured I would cross that bridge when I get to it.

Answer 1

In the following it is shown how to implement a QStackedWidget with 2 buttons, the basic idea is to layout the design, for this we analyze that a QVBoxLayout must be placed to place the QStackedWidget and another layout, this second layout will be a QHBoxLayout to have the buttons. Then we connect the signals that handle the transition between pages. Also in this example I have created 3 types of widgets that will be placed on each page.

from PyQt5.QtWidgets import *


class Widget1(QWidget):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent=parent)
        lay = QVBoxLayout(self)
        for i in range(4):
            lay.addWidget(QPushButton("{}".format(i)))

class Widget2(QWidget):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent=parent)
        lay = QVBoxLayout(self)
        for i in range(4):
            lay.addWidget(QLineEdit("{}".format(i)))

class Widget3(QWidget):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent=parent)
        lay = QVBoxLayout(self)
        for i in range(4):
            lay.addWidget(QRadioButton("{}".format(i)))

class stackedExample(QWidget):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent=parent)
        lay = QVBoxLayout(self)
        self.Stack = QStackedWidget()
        self.Stack.addWidget(Widget1())
        self.Stack.addWidget(Widget2())
        self.Stack.addWidget(Widget3())

        btnNext = QPushButton("Next")
        btnNext.clicked.connect(self.onNext)
        btnPrevious = QPushButton("Previous")
        btnPrevious.clicked.connect(self.onPrevious)
        btnLayout = QHBoxLayout()
        btnLayout.addWidget(btnPrevious)
        btnLayout.addWidget(btnNext)

        lay.addWidget(self.Stack)
        lay.addLayout(btnLayout)

    def onNext(self):
        self.Stack.setCurrentIndex((self.Stack.currentIndex()+1) % 3)

    def onPrevious(self):
        self.Stack.setCurrentIndex((self.Stack.currentIndex()-1) % 3)


if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    w = stackedExample()
    w.show()
    sys.exit(app.exec_())