Merge pull request #1700 from davep/tree-select-expand-divorce

Enhance `Tree` so that there is a expand/collapse action that is separate from select

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Added more keyboard actions and related bindings to `Input` https://github.com/Textualize/textual/pull/1676
 - Added App.scroll_sensitivity_x and App.scroll_sensitivity_y to adjust how many lines the scroll wheel moves the scroll position https://github.com/Textualize/textual/issues/928
 - Added Shift+scroll wheel and ctrl+scroll wheel to scroll horizontally
+- Added `Tree.action_toggle_node` to toggle a node without selecting, and bound it to <kbd>Space</kbd> https://github.com/Textualize/textual/issues/1433
 
 ### Changed
 

src/textual/widgets/_tree.py

@@ -284,6 +284,7 @@ class Tree(Generic[TreeDataType], ScrollView, can_focus=True):
 
     BINDINGS: ClassVar[list[BindingType]] = [
         Binding("enter", "select_cursor", "Select", show=False),
+        Binding("space", "toggle_node", "Toggle", show=False),
         Binding("up", "cursor_up", "Cursor Up", show=False),
         Binding("down", "cursor_down", "Cursor Down", show=False),
     ]
@@ -291,6 +292,7 @@ class Tree(Generic[TreeDataType], ScrollView, can_focus=True):
     | Key(s) | Description |
     | :- | :- |
     | enter | Select the current item. |
+    | space | Toggle the expand/collapsed space of the current item. |
     | up | Move the cursor up. |
     | down | Move the cursor down. |
     """
@@ -971,6 +973,7 @@ class Tree(Generic[TreeDataType], ScrollView, can_focus=True):
         self._invalidate()
 
     def action_cursor_up(self) -> None:
+        """Move the cursor up one node."""
         if self.cursor_line == -1:
             self.cursor_line = self.last_line
         else:
@@ -978,6 +981,7 @@ class Tree(Generic[TreeDataType], ScrollView, can_focus=True):
         self.scroll_to_line(self.cursor_line)
 
     def action_cursor_down(self) -> None:
+        """Move the cursor down one node."""
         if self.cursor_line == -1:
             self.cursor_line = 0
         else:
@@ -985,26 +989,50 @@ class Tree(Generic[TreeDataType], ScrollView, can_focus=True):
         self.scroll_to_line(self.cursor_line)
 
     def action_page_down(self) -> None:
+        """Move the cursor down a page's-worth of nodes."""
         if self.cursor_line == -1:
             self.cursor_line = 0
         self.cursor_line += self.scrollable_content_region.height - 1
         self.scroll_to_line(self.cursor_line)
 
     def action_page_up(self) -> None:
+        """Move the cursor up a page's-worth of nodes."""
         if self.cursor_line == -1:
             self.cursor_line = self.last_line
         self.cursor_line -= self.scrollable_content_region.height - 1
         self.scroll_to_line(self.cursor_line)
 
     def action_scroll_home(self) -> None:
+        """Move the cursor to the top of the tree."""
         self.cursor_line = 0
         self.scroll_to_line(self.cursor_line)
 
     def action_scroll_end(self) -> None:
+        """Move the cursor to the bottom of the tree.
+
+        Note:
+            Here bottom means vertically, not branch depth.
+        """
         self.cursor_line = self.last_line
         self.scroll_to_line(self.cursor_line)
 
+    def action_toggle_node(self) -> None:
+        """Toggle the expanded state of the target node."""
+        try:
+            line = self._tree_lines[self.cursor_line]
+        except IndexError:
+            pass
+        else:
+            self._toggle_node(line.path[-1])
+
     def action_select_cursor(self) -> None:
+        """Cause a select event for the target node.
+
+        Note:
+            If `auto_expand` is `True` use of this action on a non-leaf node
+            will cause both an expand/collapse event to occour, as well as a
+            selected event.
+        """
         try:
             line = self._tree_lines[self.cursor_line]
         except IndexError:

tests/tree/test_tree_messages.py

@@ -48,23 +48,26 @@ async def test_tree_node_selected_message() -> None:
         assert pilot.app.messages == ["NodeExpanded", "NodeSelected"]
 
 
+async def test_tree_node_selected_message_no_auto() -> None:
+    """Selecting a node should result in only a selected message being emitted."""
+    async with TreeApp().run_test() as pilot:
+        pilot.app.query_one(MyTree).auto_expand = False
+        await pilot.press("enter")
+        assert pilot.app.messages == ["NodeSelected"]
+
+
 async def test_tree_node_expanded_message() -> None:
     """Expanding a node should result in an expanded message being emitted."""
     async with TreeApp().run_test() as pilot:
-        await pilot.press("enter")
-        assert pilot.app.messages == ["NodeExpanded", "NodeSelected"]
+        await pilot.press("space")
+        assert pilot.app.messages == ["NodeExpanded"]
 
 
 async def test_tree_node_collapsed_message() -> None:
     """Collapsing a node should result in a collapsed message being emitted."""
     async with TreeApp().run_test() as pilot:
-        await pilot.press("enter", "enter")
-        assert pilot.app.messages == [
-            "NodeExpanded",
-            "NodeSelected",
-            "NodeCollapsed",
-            "NodeSelected",
-        ]
+        await pilot.press("space", "space")
+        assert pilot.app.messages == ["NodeExpanded", "NodeCollapsed"]
 
 
 async def test_tree_node_highlighted_message() -> None: