SelectionRectangle: ensure we remove or update selection handles if selection changes

If you make a selection with SelectionRectangle and then resize a
row, the selection handles will not move to the resized position.
Likewise, if you do a selection, but then clear the selection
by interacting with the ItemSelectionModel directly, the
selection handles will not be updated to reflect the changes.

To fix this bug, this patch will add a callback from TableView to
SelectionRectangle that can be used to notify when changes are
done outside of SelectionRectangle. This especially allows us to:

- Remove the selection handles if the active selection is cleared
  or changed programatically (or anyway not by SelectionRectangle).
- Keep the selection handles, and update their position, when rows
  or columns are merely resized.

This change also allows us to clean up qquickselectionrectangle.cpp
a bit, and remove e.g a now superfluous tap handler listener.

Task-number: QTBUG-121143
Pick-to: 6.7 6.6 6.5
Change-Id: Id170520d49bc92c0bb9d16deaba741cab6f5c553
Reviewed-by: Santhosh Kumar <santhosh.kumar.selvaraj@qt.io>

1 files changed, 4 insertions, 0 deletions

diff --git a/tests/manual/tableview/abstracttablemodel/main.qml b/tests/manual/tableview/abstracttablemodel/main.qml
index e8d1192ede..5578e86dba 100644
--- a/tests/manual/tableview/abstracttablemodel/main.qml
+++ b/tests/manual/tableview/abstracttablemodel/main.qml
@@ -198,6 +198,10 @@ ApplicationWindow {
                         ]
                         Layout.fillWidth: false
                     }
+                    Button {
+                        text: "Clear selection"
+                        onClicked: tableView.selectionModel.clearSelection()
+                    }
                 }
             }