Collapsed widget in qt with animation

CollapsedWidget.hpp

#ifndef COLLAPSED_WIDGET_H
#define COLLAPSED_WIDGET_H
#include <QFrame>
#include <QGridLayout>
#include <QParallelAnimationGroup>
#include <QPropertyAnimation>
#include <QScrollArea>
#include <QToolButton>
#include <QWidget>

class CollapsedWidget : public QWidget {
  Q_OBJECT
 private:
  QGridLayout mainLayout;
  QToolButton toggleButton;
  QFrame headerLine;
  QParallelAnimationGroup toggleAnimation;
  QScrollArea contentArea;
  int animationDuration{300};

 public:
  explicit CollapsedWidget(const QString &title = "",
                           const int animationDuration = 300,
                           QWidget *parent = 0)
      : QWidget(parent), animationDuration(animationDuration) {
    toggleButton.setStyleSheet("QToolButton { border: none; }");
    toggleButton.setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
    toggleButton.setArrowType(Qt::ArrowType::RightArrow);
    toggleButton.setText(title);
    toggleButton.setCheckable(true);
    toggleButton.setChecked(false);

    headerLine.setFrameShape(QFrame::HLine);
    headerLine.setFrameShadow(QFrame::Sunken);
    headerLine.setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Maximum);

    contentArea.setStyleSheet(
        "QScrollArea { background-color: white; border: none; }");
    contentArea.setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
    // start out collapsed
    contentArea.setMaximumHeight(0);
    contentArea.setMinimumHeight(0);
    // let the entire widget grow and shrink with its content
    toggleAnimation.addAnimation(new QPropertyAnimation(this, "minimumHeight"));
    toggleAnimation.addAnimation(new QPropertyAnimation(this, "maximumHeight"));
    toggleAnimation.addAnimation(
        new QPropertyAnimation(&contentArea, "maximumHeight"));
    // don't waste space
    mainLayout.setVerticalSpacing(0);
    mainLayout.setContentsMargins(0, 0, 0, 0);
    int row = 0;
    mainLayout.addWidget(&toggleButton, row, 0, 1, 1, Qt::AlignLeft);
    mainLayout.addWidget(&headerLine, row++, 2, 1, 1);
    mainLayout.addWidget(&contentArea, row, 0, 1, 3);
    setLayout(&mainLayout);
    QObject::connect(
        &toggleButton, &QToolButton::clicked, [this](const bool checked) {
          toggleButton.setArrowType(checked ? Qt::ArrowType::DownArrow
                                            : Qt::ArrowType::RightArrow);
          toggleAnimation.setDirection(checked ? QAbstractAnimation::Forward
                                               : QAbstractAnimation::Backward);
          toggleAnimation.start();
        });
  }
  void setContentLayout(QLayout &contentLayout) {
    delete contentArea.layout();
    contentArea.setLayout(&contentLayout);
    const auto collapsedHeight =
        sizeHint().height() - contentArea.maximumHeight();
    auto contentHeight = contentLayout.sizeHint().height();
    for (int i = 0; i < toggleAnimation.animationCount() - 1; ++i) {
      QPropertyAnimation *spoilerAnimation =
          static_cast<QPropertyAnimation *>(toggleAnimation.animationAt(i));
      spoilerAnimation->setDuration(animationDuration);
      spoilerAnimation->setStartValue(collapsedHeight);
      spoilerAnimation->setEndValue(collapsedHeight + contentHeight);
    }
    QPropertyAnimation *contentAnimation = static_cast<QPropertyAnimation *>(
        toggleAnimation.animationAt(toggleAnimation.animationCount() - 1));
    contentAnimation->setDuration(animationDuration);
    contentAnimation->setStartValue(0);
    contentAnimation->setEndValue(contentHeight);
  }
};

#COLLAPSED_WIDGET_H  // COLLAPSED_WIDGET_H