In this section, we are going to learn about treeviews, a commonly used component in many UI examples (a classical example being the on-disk folder structure in many operating systems' shells).
A very common data structure is the tree. Basically, data is provided with a hierarchical relationship between items so each item can be seen as a parent of other items. A typical example of this kind of nested list structure is how filesystem objects get represented (some filesystem entries that are used to call folders or directories can have children, that is, files or folders entries).
FMX has a TTreeView component suitable for representing such data structures. Basically, you can see it as a scrollable list of items where each item can contain other items. Sub-items are generally indented horizontally more than their parent and parents are generally expandable and collapsible. These characteristics make the hierarchy across items very evident to the user...