Add a handler for ListView.SearchForVirtualItem in winforms backend for keyboard navigation in tables and detailed lists

android/tests_backend/widgets/table.py

@@ -94,3 +94,6 @@ def typeface(self):
     @property
     def text_size(self):
         return self._row_view(0).getChildAt(0).getTextSize()
+
+    async def acquire_keyboard_focus(self):
+        pytest.skip("test not implemented for this platform")

changes/2956.bugfix.rst

@@ -0,0 +1 @@
+Multi-letter keyboard navigation in Tables and DetailedLists with the winforms backend is now functional.

cocoa/tests_backend/widgets/base.py

@@ -114,6 +114,8 @@ async def type_character(self, char, modifierFlags=0):
         key_code = {
             "<backspace>": 51,
             "<esc>": 53,
+            "<down>": 125,
+            "<up>": 126,
             " ": 49,
             "\n": 36,
             "a": 0,

cocoa/tests_backend/widgets/table.py

@@ -13,6 +13,7 @@ class TableProbe(SimpleProbe):
     native_class = NSScrollView
     supports_icons = 2  # All columns
     supports_keyboard_shortcuts = True
+    supports_keyboard_boundary_shortcuts = False
     supports_widgets = True
 
     def __init__(self, widget):
@@ -144,3 +145,11 @@ async def activate_row(self, row):
             delay=0.1,
             clickCount=2,
         )
+
+    async def acquire_keyboard_focus(self):
+        self.native_table.window.makeFirstResponder(
+            self.native_table
+        )  # switch to widget.focus() when possible (#2972).
+        # Insure first row is selected.
+        await self.type_character("<down>")
+        await self.type_character("<up>")

gtk/tests_backend/widgets/table.py

@@ -84,3 +84,6 @@ async def activate_row(self, row):
             Gtk.TreePath(row),
             self.native_table.get_columns()[0],
         )
+
+    async def acquire_keyboard_focus(self):
+        pytest.skip("test not implemented for this platform")

testbed/tests/widgets/test_table.py

@@ -159,6 +159,50 @@ async def test_scroll(widget, probe):
     assert -100 < probe.scroll_position <= 0
 
 
+async def test_keyboard_navigation(widget, source, probe):
+    """The list can be navigated using a keyboard."""
+    await probe.acquire_keyboard_focus()
+    await probe.redraw("First row selected")
+    assert widget.selection == widget.data[0]
+
+    # Navigate down with letter, arrow, letter.
+    await probe.type_character("a")
+    await probe.redraw("Letter pressed - second row selected")
+    assert widget.selection == widget.data[1]
+    await probe.type_character("<down>")
+    await probe.redraw("Down arrow pressed - third row selected")
+    assert widget.selection == widget.data[2]
+    await probe.type_character("a")
+    await probe.redraw("Letter pressed - forth row selected")
+    assert widget.selection == widget.data[3]
+
+    # Select the last item with the end key if supported then wrap around.
+    if probe.supports_keyboard_boundary_shortcuts:
+        await probe.type_character("<end>")
+        await probe.redraw("Last row is selected")
+        assert widget.selection == widget.data[-1]
+        # Navigate by 1 item, wrapping around.
+        await probe.type_character("a")
+        await probe.redraw("Letter pressed - first row is selected")
+    else:
+        await probe.type_character("<up>")
+        await probe.type_character("<up>")
+        await probe.type_character("<up>")
+        await probe.redraw("Up arrow pressed thrice - first row is selected")
+    assert widget.selection == widget.data[0]
+
+    # Type a letter that no items start with to verify the selection doesn't change.
+    await probe.type_character("x")
+    await probe.redraw("Invalid letter pressed - first row is still selected")
+    assert widget.selection == widget.data[0]
+
+    # clear the table and verify with an empty selection.
+    widget.data.clear()
+    await probe.type_character("a")
+    await probe.redraw("Letter pressed - no row selected")
+    assert not widget.selection
+
+
 async def test_select(widget, probe, source, on_select_handler):
     """Rows can be selected"""
     # Initial selection is empty

winforms/src/toga_winforms/widgets/table.py

@@ -63,6 +63,9 @@ def create(self):
         self.native.CacheVirtualItems += WeakrefCallable(
             self.winforms_cache_virtual_items
         )
+        self.native.SearchForVirtualItem += WeakrefCallable(
+            self.winforms_search_for_virtual_item
+        )
         self.native.VirtualItemsSelectionRangeChanged += WeakrefCallable(
             self.winforms_item_selection_changed
         )
@@ -108,6 +111,49 @@ def winforms_cache_virtual_items(self, sender, e):
         for i in range(new_length):
             self._cache.append(self._new_item(i + self._first_item))
 
+    def winforms_search_for_virtual_item(self, sender, e):
+        if (
+            not e.IsTextSearch or not self._accessors or not self._data
+        ):  # pragma: no cover
+            # If this list is empty, or has no columns, or it's an unsupported search
+            # type, there's no search to be done. These situation are difficult to
+            # trigger in CI; they're here as a safety catch.
+            return
+        find_previous = e.Direction in [
+            WinForms.SearchDirectionHint.Up,
+            WinForms.SearchDirectionHint.Left,
+        ]
+        i = e.StartIndex
+        found_item = False
+        while True:
+            # It is possible for e.StartIndex to be received out-of-range if the user
+            # performs keyboard navigation at its edge, so check before accessing data
+            if i < 0:  # pragma: no cover
+                # This could happen if this event is fired searching backwards,
+                # however this should not happen in Toga's use of it.
+                # i = len(self._data) - 1
+                raise NotImplementedError("backwards search unsupported")
+            elif i >= len(self._data):
+                i = 0
+            if (
+                self._item_text(self._data[i], self._accessors[0])[
+                    : len(e.Text)
+                ].lower()
+                == e.Text.lower()
+            ):
+                found_item = True
+                break
+            if find_previous:  # pragma: no cover
+                # Toga does not currently need backwards searching functionality.
+                # i -= 1
+                raise NotImplementedError("backwards search unsupported")
+            else:
+                i += 1
+            if i == e.StartIndex:
+                break
+        if found_item:
+            e.Index = i
+
     def winforms_item_selection_changed(self, sender, e):
         self.interface.on_select()
 
@@ -156,19 +202,8 @@ def icon(attr):
 
             return None if icon is None else icon._impl
 
-        def text(attr):
-            val = getattr(item, attr, None)
-            if isinstance(val, toga.Widget):
-                warn("Winforms does not support the use of widgets in cells")
-                val = None
-            if isinstance(val, tuple):
-                val = val[1]
-            if val is None:
-                val = self.interface.missing_value
-            return str(val)
-
         lvi = WinForms.ListViewItem(
-            [text(attr) for attr in self._accessors],
+            [self._item_text(item, attr) for attr in self._accessors],
         )
 
         # If the table has accessors, populate the icons for the table.
@@ -181,6 +216,17 @@ def text(attr):
 
         return lvi
 
+    def _item_text(self, item, attr):
+        val = getattr(item, attr, None)
+        if isinstance(val, toga.Widget):
+            warn("Winforms does not support the use of widgets in cells")
+            val = None
+        if isinstance(val, tuple):
+            val = val[1]
+        if val is None:
+            val = self.interface.missing_value
+        return str(val)
+
     def _image_index(self, icon):
         images = self.native.SmallImageList.Images
         key = str(icon.path)

winforms/tests_backend/probe.py

@@ -10,7 +10,7 @@
 
 KEY_CODES = {
     f"<{name}>": f"{{{name.upper()}}}"
-    for name in ["esc", "up", "down", "left", "right"]
+    for name in ["esc", "up", "down", "left", "right", "home", "end"]
 }
 KEY_CODES.update(
     {

winforms/tests_backend/widgets/table.py

@@ -15,6 +15,7 @@ class TableProbe(SimpleProbe):
     background_supports_alpha = False
     supports_icons = 1  # First column only
     supports_keyboard_shortcuts = False
+    supports_keyboard_boundary_shortcuts = True
     supports_widgets = False
 
     @property
@@ -99,3 +100,9 @@ async def activate_row(self, row):
                 delta=0,
             )
         )
+
+    async def acquire_keyboard_focus(self):
+        await self.type_character(
+            "\t"
+        )  # switch to widget.focus() when possible (#2972)
+        await self.type_character(" ")  # select first row