Qt: Add CollapsibleWidget

src/duckstation-qt/collapsiblewidget.h

@@ -0,0 +1,27 @@
+// https://stackoverflow.com/questions/32476006/how-to-make-an-expandable-collapsable-section-widget-in-qt
+
+#pragma once
+
+#include <QtCore/QParallelAnimationGroup>
+#include <QtWidgets/QScrollArea>
+#include <QtWidgets/QToolButton>
+#include <QtWidgets/QVBoxLayout>
+#include <QtWidgets/QWidget>
+
+class CollapsibleWidget : public QWidget
+{
+  Q_OBJECT
+private:
+  QVBoxLayout mainLayout;
+  QToolButton toggleButton;
+  QParallelAnimationGroup toggleAnimation;
+  QScrollArea contentArea;
+  int animationDuration{300};
+
+public:
+  explicit CollapsibleWidget(const QString& title = "", const int animationDuration = 300, QWidget* parent = 0);
+
+  QScrollArea* getScrollArea() { return &contentArea; }
+
+  void setContentLayout(QLayout* contentLayout);
+};