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Merge pull request #1595 from Textualize/fix-1196-add-focus-selector

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Fix 1196 add focus selector
This commit is contained in:
Rodrigo Girão Serrão
2023-01-17 16:48:34 +00:00
committed by GitHub
parent fc2073386c 88a1fe013c
commit 9c7a949093
3 changed files with 233 additions and 41 deletions
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1
CHANGELOG.md
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@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
- Added a `Tree.NodeHighlighted` message, giving a `on_tree_node_highlighted` event handler https://github.com/Textualize/textual/issues/1400
- Added a `inherit_component_classes` subclassing parameter to control whether or not component classes are inherited from base classes https://github.com/Textualize/textual/issues/1399
- Added `diagnose` as a `textual` command https://github.com/Textualize/textual/issues/1542
- Added an optional parameter `selector` to the methods `Screen.focus_next` and `Screen.focus_previous` that enable using a CSS selector to narrow down which widgets can get focus https://github.com/Textualize/textual/issues/1196
### Changed

104
src/textual/screen.py
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@@ -9,6 +9,9 @@ from rich.style import Style
from . import errors, events, messages
from ._callback import invoke
from ._compositor import Compositor, MapGeometry
from .css.match import match
from .css.parse import parse_selectors
from .dom import DOMNode
from .timer import Timer
from ._types import CallbackType
from .geometry import Offset, Region, Size
@@ -178,54 +181,105 @@ class Screen(Widget):
return widgets
def _move_focus(self, direction: int = 0) -> Widget | None:
def _move_focus(
self, direction: int = 0, selector: str | type[DOMNode.ExpectType] = "*"
) -> Widget | None:
"""Move the focus in the given direction.
If no widget is currently focused, this will focus the first focusable widget.
If no focusable widget matches the given CSS selector, focus is set to `None`.
Args:
direction (int, optional): 1 to move forward, -1 to move backward, or
0 to keep the current focus.
selector (str | type[DOMNode.ExpectType], optional): CSS selector to filter
what nodes can be focused.
Returns:
Widget | None: Newly focused widget, or None for no focus.
Widget | None: Newly focused widget, or None for no focus. If the return
is not `None`, then it is guaranteed that the widget returned matches
the CSS selectors given in the argument.
"""
focusable_widgets = self.focus_chain
if not isinstance(selector, str):
selector = selector.__name__
selector_set = parse_selectors(selector)
focus_chain = self.focus_chain
filtered_focus_chain = (
node for node in focus_chain if match(selector_set, node)
)
if not focusable_widgets:
if not focus_chain:
# Nothing focusable, so nothing to do
return self.focused
if self.focused is None:
# Nothing currently focused, so focus the first one
self.set_focus(focusable_widgets[0])
# Nothing currently focused, so focus the first one.
to_focus = next(filtered_focus_chain, None)
self.set_focus(to_focus)
return self.focused
# Ensure focus will be in a node that matches the selectors.
if not direction and not match(selector_set, self.focused):
direction = 1
try:
# Find the index of the currently focused widget
current_index = focus_chain.index(self.focused)
except ValueError:
# Focused widget was removed in the interim, start again
self.set_focus(next(filtered_focus_chain, None))
else:
try:
# Find the index of the currently focused widget
current_index = focusable_widgets.index(self.focused)
except ValueError:
# Focused widget was removed in the interim, start again
self.set_focus(focusable_widgets[0])
else:
# Only move the focus if we are currently showing the focus
if direction:
current_index = (current_index + direction) % len(focusable_widgets)
self.set_focus(focusable_widgets[current_index])
# Only move the focus if we are currently showing the focus
if direction:
to_focus: Widget | None = None
chain_length = len(focus_chain)
for step in range(1, len(focus_chain) + 1):
node = focus_chain[
(current_index + direction * step) % chain_length
]
if match(selector_set, node):
to_focus = node
break
self.set_focus(to_focus)
return self.focused
def focus_next(self) -> Widget | None:
"""Focus the next widget.
def focus_next(
self, selector: str | type[DOMNode.ExpectType] = "*"
) -> Widget | None:
"""Focus the next widget, optionally filtered by a CSS selector.
If no widget is currently focused, this will focus the first focusable widget.
If no focusable widget matches the given CSS selector, focus is set to `None`.
Args:
selector (str | type[DOMNode.ExpectType], optional): CSS selector to filter
what nodes can be focused.
Returns:
Widget | None: Newly focused widget, or None for no focus.
Widget | None: Newly focused widget, or None for no focus. If the return
is not `None`, then it is guaranteed that the widget returned matches
the CSS selectors given in the argument.
"""
return self._move_focus(1)
return self._move_focus(1, selector)
def focus_previous(self) -> Widget | None:
"""Focus the previous widget.
def focus_previous(
self, selector: str | type[DOMNode.ExpectType] = "*"
) -> Widget | None:
"""Focus the previous widget, optionally filtered by a CSS selector.
If no widget is currently focused, this will focus the first focusable widget.
If no focusable widget matches the given CSS selector, focus is set to `None`.
Args:
selector (str | type[DOMNode.ExpectType], optional): CSS selector to filter
what nodes can be focused.
Returns:
Widget | None: Newly focused widget, or None for no focus.
Widget | None: Newly focused widget, or None for no focus. If the return
is not `None`, then it is guaranteed that the widget returned matches
the CSS selectors given in the argument.
"""
return self._move_focus(-1)
return self._move_focus(-1, selector)
def _reset_focus(
self, widget: Widget, avoiding: list[Widget] | None = None

169
tests/test_focus.py
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@@ -1,3 +1,5 @@
import pytest
from textual.app import App
from textual.screen import Screen
from textual.widget import Widget
@@ -15,6 +17,28 @@ class ChildrenFocusableOnly(Widget, can_focus=False, can_focus_children=True):
pass
@pytest.fixture
def screen() -> Screen:
app = App()
app._set_active()
app.push_screen(Screen())
screen = app.screen
# The classes even/odd alternate along the focus chain.
# The classes in/out identify nested widgets.
screen._add_children(
Focusable(id="foo", classes="a"),
NonFocusable(id="bar"),
Focusable(Focusable(id="Paul", classes="c"), id="container1", classes="b"),
NonFocusable(Focusable(id="Jessica", classes="a"), id="container2"),
Focusable(id="baz", classes="b"),
ChildrenFocusableOnly(Focusable(id="child", classes="c")),
)
return screen
def test_focus_chain():
app = App()
app._set_active()
@@ -38,22 +62,7 @@ def test_focus_chain():
assert focus_chain == ["foo", "container1", "Paul", "baz", "child"]
def test_focus_next_and_previous():
app = App()
app._set_active()
app.push_screen(Screen())
screen = app.screen
screen._add_children(
Focusable(id="foo"),
NonFocusable(id="bar"),
Focusable(Focusable(id="Paul"), id="container1"),
NonFocusable(Focusable(id="Jessica"), id="container2"),
Focusable(id="baz"),
ChildrenFocusableOnly(Focusable(id="child")),
)
def test_focus_next_and_previous(screen: Screen):
assert screen.focus_next().id == "foo"
assert screen.focus_next().id == "container1"
assert screen.focus_next().id == "Paul"
@@ -64,3 +73,131 @@ def test_focus_next_and_previous():
assert screen.focus_previous().id == "Paul"
assert screen.focus_previous().id == "container1"
assert screen.focus_previous().id == "foo"
def test_focus_next_wrap_around(screen: Screen):
"""Ensure focusing the next widget wraps around the focus chain."""
screen.set_focus(screen.query_one("#child"))
assert screen.focused.id == "child"
assert screen.focus_next().id == "foo"
def test_focus_previous_wrap_around(screen: Screen):
"""Ensure focusing the previous widget wraps around the focus chain."""
screen.set_focus(screen.query_one("#foo"))
assert screen.focused.id == "foo"
assert screen.focus_previous().id == "child"
def test_wrap_around_selector(screen: Screen):
"""Ensure moving focus in both directions wraps around the focus chain."""
screen.set_focus(screen.query_one("#foo"))
assert screen.focused.id == "foo"
assert screen.focus_previous("#Paul").id == "Paul"
assert screen.focus_next("#foo").id == "foo"
def test_no_focus_empty_selector(screen: Screen):
"""Ensure focus is cleared when selector matches nothing."""
assert screen.focus_next("#bananas") is None
assert screen.focus_previous("#bananas") is None
screen.set_focus(screen.query_one("#foo"))
assert screen.focused is not None
assert screen.focus_next("bananas") is None
assert screen.focused is None
screen.set_focus(screen.query_one("#foo"))
assert screen.focused is not None
assert screen.focus_previous("bananas") is None
assert screen.focused is None
def test_focus_next_and_previous_with_type_selector(screen: Screen):
"""Move focus with a selector that matches the currently focused node."""
screen.set_focus(screen.query_one("#Paul"))
assert screen.focused.id == "Paul"
assert screen.focus_next(Focusable).id == "baz"
assert screen.focus_next(Focusable).id == "child"
assert screen.focus_previous(Focusable).id == "baz"
assert screen.focus_previous(Focusable).id == "Paul"
assert screen.focus_previous(Focusable).id == "container1"
assert screen.focus_previous(Focusable).id == "foo"
def test_focus_next_and_previous_with_str_selector(screen: Screen):
"""Move focus with a selector that matches the currently focused node."""
screen.set_focus(screen.query_one("#foo"))
assert screen.focused.id == "foo"
assert screen.focus_next(".a").id == "foo"
assert screen.focus_next(".c").id == "Paul"
assert screen.focus_next(".c").id == "child"
assert screen.focus_previous(".c").id == "Paul"
assert screen.focus_previous(".a").id == "foo"
def test_focus_next_and_previous_with_type_selector_without_self():
"""Test moving the focus with a selector that does not match the currently focused node."""
app = App()
app._set_active()
app.push_screen(Screen())
screen = app.screen
from textual.containers import Horizontal, Vertical
from textual.widgets import Button, Checkbox, Input
screen._add_children(
Vertical(
Horizontal(
Input(id="w3"),
Checkbox(id="w4"),
Input(id="w5"),
Button(id="w6"),
Checkbox(id="w7"),
id="w2",
),
Horizontal(
Button(id="w9"),
Checkbox(id="w10"),
Button(id="w11"),
Input(id="w12"),
Input(id="w13"),
id="w8",
),
id="w1",
)
)
screen.set_focus(screen.query_one("#w3"))
assert screen.focused.id == "w3"
assert screen.focus_next(Button).id == "w6"
assert screen.focus_next(Checkbox).id == "w7"
assert screen.focus_next(Input).id == "w12"
assert screen.focus_previous(Button).id == "w11"
assert screen.focus_previous(Checkbox).id == "w10"
assert screen.focus_previous(Button).id == "w9"
assert screen.focus_previous(Input).id == "w5"
def test_focus_next_and_previous_with_str_selector_without_self(screen: Screen):
"""Test moving the focus with a selector that does not match the currently focused node."""
screen.set_focus(screen.query_one("#foo"))
assert screen.focused.id == "foo"
assert screen.focus_next(".c").id == "Paul"
assert screen.focus_next(".b").id == "baz"
assert screen.focus_next(".c").id == "child"
assert screen.focus_previous(".a").id == "foo"
assert screen.focus_previous(".a").id == "foo"
assert screen.focus_previous(".b").id == "baz"