Qt layout does not reflect groupbox size change

Question

I am trying to make UI with animated collapsible groupBox , using PyQt5 and QT Creator.

If groupBox is unchecked its height shrinks to some small value, if groupBox is checked its height expands to sizeHint().height()

The problem is when another groupBox is present in layout. The another groupBox position does not reflect that collapsed groupBox size changed.

Is there way how to force bottom groupBox to move with collapsing groupBox ?

Here how it looks like:

---

Additional information

UI layout:

groupBox resizing implementation:

my_ui._ui.groupBox.toggled.connect(my_ui.group_box_size_change)

def group_box_size_change(self):
    duration = 1000
    self.animaiton_gb = QtCore.QPropertyAnimation(self._ui.groupBox, b"size")
    self.animaiton_gb.setDuration(duration)

    self.animaiton_gb.setStartValue(QtCore.QSize(self._ui.groupBox.width(),  self._ui.groupBox.height()))

    if self._ui.groupBox.isChecked():
        self.animaiton_gb.setEndValue(QtCore.QSize(self._ui.groupBox.width(), self._ui.groupBox.sizeHint().height()))
    else:
        self.animaiton_gb.setEndValue(QtCore.QSize(self._ui.groupBox.width(), 49))

    self.animaiton_gb.start()

Answer 1

Considering my old answer to a question where a similar widget was required, the following is the solution. In that case, the strategy is to use a QScrollArea as a container and use the minimumHeight and maximumHeight properties.

from PyQt5 import QtCore, QtGui, QtWidgets


class CollapsibleBox(QtWidgets.QGroupBox):
    def __init__(self, title="", parent=None):
        super(CollapsibleBox, self).__init__(title, parent)
        self.setCheckable(True)
        self.setChecked(False)
        self.toggled.connect(self.on_pressed)
        self.toggle_animation = QtCore.QParallelAnimationGroup(self)

        self.content_area = QtWidgets.QScrollArea(maximumHeight=0, minimumHeight=0)
        self.content_area.setSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Fixed)
        self.content_area.setFrameShape(QtWidgets.QFrame.NoFrame)

        lay = QtWidgets.QVBoxLayout(self)
        lay.setSpacing(0)
        lay.setContentsMargins(0, 0, 0, 0)
        lay.addWidget(self.content_area)

        self.toggle_animation.addAnimation(QtCore.QPropertyAnimation(self, b"minimumHeight"))
        self.toggle_animation.addAnimation(QtCore.QPropertyAnimation(self, b"maximumHeight"))
        self.toggle_animation.addAnimation(QtCore.QPropertyAnimation(self.content_area, b"maximumHeight"))

    @QtCore.pyqtSlot(bool)
    def on_pressed(self, checked):
        self.toggle_animation.setDirection(QtCore.QAbstractAnimation.Forward if checked else QtCore.QAbstractAnimation.Backward)
        self.toggle_animation.start()

    def setContentLayout(self, layout):
        lay = self.content_area.layout()
        del lay
        self.content_area.setLayout(layout)
        collapsed_height = self.sizeHint().height() - self.content_area.maximumHeight()
        content_height = layout.sizeHint().height()
        for i in range(self.toggle_animation.animationCount()):
            animation = self.toggle_animation.animationAt(i)
            animation.setDuration(500)
            animation.setStartValue(collapsed_height)
            animation.setEndValue(collapsed_height + content_height)

        content_animation = self.toggle_animation.animationAt(self.toggle_animation.animationCount() - 1)
        content_animation.setDuration(500)
        content_animation.setStartValue(0)
        content_animation.setEndValue(content_height)

if __name__ == '__main__':
    import sys
    import random

    app = QtWidgets.QApplication(sys.argv)
    w = QtWidgets.QMainWindow()
    scroll = QtWidgets.QScrollArea()
    content = QtWidgets.QWidget()
    scroll.setWidget(content)
    scroll.setWidgetResizable(True)
    vlay = QtWidgets.QVBoxLayout(content)
    counter = 0
    for i in range(10):
        box = CollapsibleBox("Collapsible Box Header-{}".format(i))
        vlay.addWidget(box)
        lay = QtWidgets.QVBoxLayout()
        for j in range(8):
            btn = QtWidgets.QPushButton("PushButton-{}".format(counter))       
            lay.addWidget(btn)
            counter += 1
        box.setContentLayout(lay)
    vlay.addStretch()
    w.setCentralWidget(scroll)
    w.resize(240, 480)
    w.show()

    sys.exit(app.exec_())