From d864674a1f67ff8aba476d3a82be5c07b9c39e57 Mon Sep 17 00:00:00 2001
From: Vesna Tanko <tankovesna@hotmail.com>
Date: Tue, 14 May 2024 19:31:00 +0200
Subject: [PATCH] ListViewFilter: Retain selection when filtering (#270)

ListViewFilter: Retain selection when filtering
---
 orangewidget/utils/listview.py            | 25 ++++++++++++++++++++++-
 orangewidget/utils/tests/test_listview.py | 15 ++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/orangewidget/utils/listview.py b/orangewidget/utils/listview.py
index dda8e0836..3d9f43306 100644
--- a/orangewidget/utils/listview.py
+++ b/orangewidget/utils/listview.py
@@ -10,8 +10,11 @@
     QSortFilterProxyModel,
     QItemSelection,
     QSize,
+    QItemSelectionModel,
 )
 
+from orangewidget.utils.itemmodels import signal_blocking
+
 
 class ListViewFilter(QListView):
     """
@@ -27,6 +30,7 @@ def __init__(
             **kwargs
     ):
         super().__init__(*args, **kwargs)
+        self.__selection = QItemSelection()
         self.__search = QLineEdit(self, placeholderText="Filter...")
         self.__search.textEdited.connect(self.__on_text_edited)
         self.__preferred_size = preferred_size
@@ -40,9 +44,28 @@ def __init__(
         assert isinstance(proxy, QSortFilterProxyModel)
         super().setModel(proxy)
         self.set_source_model(model)
+        self.selectionModel().selectionChanged.connect(self.__on_sel_changed)
+
+    def __on_sel_changed(
+            self,
+            selected: QItemSelection,
+            deselected: QItemSelection
+    ):
+        selected = self.model().mapSelectionToSource(selected)
+        deselected = self.model().mapSelectionToSource(deselected)
+        self.__selection.merge(selected, QItemSelectionModel.Select)
+        self.__selection.merge(deselected, QItemSelectionModel.Deselect)
+        self.__select()
 
     def __on_text_edited(self, string: str):
-        self.model().setFilterFixedString(string)
+        with signal_blocking(self.selectionModel()):
+            self.model().setFilterFixedString(string)
+            self.__select()
+
+    def __select(self):
+        selection = self.model().mapSelectionFromSource(self.__selection)
+        self.selectionModel().select(selection,
+                                     QItemSelectionModel.ClearAndSelect)
 
     def setModel(self, _):
         raise TypeError("The model cannot be changed. "
diff --git a/orangewidget/utils/tests/test_listview.py b/orangewidget/utils/tests/test_listview.py
index b43ef8340..aeb91730b 100644
--- a/orangewidget/utils/tests/test_listview.py
+++ b/orangewidget/utils/tests/test_listview.py
@@ -134,6 +134,21 @@ def test_set_proxy(self):
     def test_set_proxy_raises(self):
         self.assertRaises(Exception, ListViewFilter, proxy=PyListModel())
 
+    def test_selection(self):
+        view = ListViewFilter()
+        view.model().setSourceModel(PyListModel(["one", "two", "three"]))
+        sel_model = view.selectionModel()
+        selected_row = 0
+        index = view.model().index(selected_row, 0)
+        sel_model.select(index, sel_model.ClearAndSelect)
+        self.assertEqual(sel_model.selectedRows(0)[0].row(), selected_row)
+
+        view._ListViewFilter__search.textEdited.emit("two")
+        self.assertEqual(len(sel_model.selectedRows(0)), 0)
+
+        view._ListViewFilter__search.textEdited.emit("")
+        self.assertEqual(sel_model.selectedRows(0)[0].row(), selected_row)
+
 
 if __name__ == "__main__":
     unittest.main()