This work is already done (and more correctly) by the parent class
(AbstractView) if we just let it take care of the event instead.
Fixes the root cause of #4096.
Views now have a cursor index (retrievable via cursor_index()) which
is separate from the selection.
Until now, we've been using the first entry in the selection as
"the cursor", which gets messy whenever you want to select more than
one index in the model.
When setting the cursor, the selection is implicitly updated as well
to maintain the old behavior (for the most part.)
Going forward, this will make it much easier to implement things like
shift-select (extend selection from cursor) and such. :^)
A view can now be told to move its cursor in one of multiple directions
as specified by the CursorMovement enum.
View subclasses can override move_cursor(CursorMovement) to implement
their own cursor behavior. By default, AbstractView::move_cursor() is
a no-op.
This patch improves code sharing between TableView and TreeView. :^)
If both the row and column headers are visible, we now also show a
button in the top left corner. This avoids the headers overlapping
each other when you scroll the contents.
In the future, this could be hooked up to a "select all" action.
This patch introduces the HeaderView class, which is a widget that
implements the column headers of TableView and TreeView.
This greatly simplifies event management in the view implementations
and also makes it much easier to eventually implement row headers.
This patchset adds a few getters/setters to AbstractTableView to make
its looks more customisable:
- Header width & text alignment
- Default column width
- Ability to disable selected row highlighting
This is really just a workaround to keep SystemMonitor's process table
working right wrt selection retention during resorts (while also doing
full index invalidation on things like ProfileViewer inversion.)
It's starting to feel like the model abstraction is not super great
and we'll need a better approach if we want to actually build some more
dynamic functionality into our views.
AbstractView does not know which column it's displaying which makes it
impossible to implement the select_all functionality up there. Now
descendants override the pure virtual select_all method and implement
it themselves.
