TreeView: Track model indexes during selection

As we keep track of the previous user-selected row,
it can happen that that row is no longer part of the
TreeModelAdaptor items if the user collapses it or
any of its ancestors (collapsing a node doesn't update
the current selection). This will result on the row
index pointing to the wrong entry in the model (or a
completely invalid one).

Instead, we now track the selection with QModelIndexes
making it more robust to branch expansion and collapse
in the view. We'll still need to account for model changes
which means that, in the future, we should invalidate
the previous user-selected item.

Change-Id: I54ba2582e65515eef95d5f8ad755a8c68568d7ad
Task-number: QTBUG-46891
Reviewed-by: Caroline Chao <caroline.chao@theqtcompany.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/tests/auto/controls/data/tst_treeview.qml b/tests/auto/controls/data/tst_treeview.qml
index 9db58f14..6e17e318 100644
--- a/tests/auto/controls/data/tst_treeview.qml
+++ b/tests/auto/controls/data/tst_treeview.qml
@@ -785,5 +785,34 @@ Item {
             compare(treeIndex.column, modelIndex.column)
             compare(treeIndex.internalId, modelIndex.internalId)
         }
+
+        function test_QTBUG_46891_selection_collapse_parent()
+        {
+            var component = Qt.createComponent("treeview/treeview_1.qml")
+            compare(component.status, Component.Ready)
+            var tree = component.createObject(container);
+            verify(tree !== null, "tree created is null")
+            var model = tree.model
+            model.removeRows(1, 9)
+            model.removeRows(1, 9, model.index(0, 0))
+            waitForRendering(tree)
+
+            var selectionModel = Qt.createQmlObject(testCase.instance_selectionModel, container, '')
+            selectionModel.model = tree.model
+            tree.selection = selectionModel
+            tree.selectionMode = SelectionMode.ExtendedSelection
+
+            var parentItem = tree.model.index(0, 0)
+            tree.expand(parentItem)
+            verify(tree.isExpanded(parentItem))
+
+            wait(100)
+            mouseClick(tree, semiIndent + 50, 20 + 100, Qt.LeftButton)
+            verify(selectionModel.isSelected(tree.currentIndex))
+
+            tree.collapse(parentItem)
+            mouseClick(tree, semiIndent + 50, 20 + 50, Qt.LeftButton)
+            verify(selectionModel.isSelected(parentItem))
+        }
     }
 }