ui: child widget support (#37594)

* child widgets!

* cmt

* missing

* group

* add debug flag

* use in scroller

* not clean yet

* restore

selfdrive/ui/mici/layouts/home.py

@@ -111,6 +111,7 @@ class MiciHomeLayout(Widget):
     self._version_commit_label = MiciLabel("", font_size=36, color=rl.GRAY, font_weight=FontWeight.ROMAN)
 
   def show_event(self):
+    super().show_event()
     self._version_text = self._get_version_text()
     self._update_params()
 

system/ui/widgets/__init__.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 import abc
 import pyray as rl
 from enum import IntEnum
+from typing import TypeVar
 from collections.abc import Callable
 from openpilot.system.ui.lib.application import gui_app, MousePos, MAX_TOUCH_SLOTS, MouseEvent
 
@@ -13,6 +14,10 @@ except ImportError:
     awake = True
   device = Device()
 
+W = TypeVar('W', bound='Widget')
+
+DEBUG = True
+
 
 class DialogResult(IntEnum):
   CANCEL = 0
@@ -24,11 +29,14 @@ class Widget(abc.ABC):
   def __init__(self):
     self._rect: rl.Rectangle = rl.Rectangle(0, 0, 0, 0)
     self._parent_rect: rl.Rectangle | None = None
+    self._children: list[Widget] = []
+
+    self._enabled: bool | Callable[[], bool] = True
+    self._is_visible: bool | Callable[[], bool] = True
+
     self.__is_pressed = [False] * MAX_TOUCH_SLOTS
     # if current mouse/touch down started within the widget's rectangle
     self.__tracking_is_pressed = [False] * MAX_TOUCH_SLOTS
-    self._enabled: bool | Callable[[], bool] = True
-    self._is_visible: bool | Callable[[], bool] = True
     self._touch_valid_callback: Callable[[], bool] | None = None
     self._click_delay: float | None = None  # seconds to hold is_pressed after release
     self._click_release_time: float | None = None
@@ -197,12 +205,37 @@ class Widget(abc.ABC):
     """Optionally handle mouse events. This is called before rendering."""
     # Default implementation does nothing, can be overridden by subclasses
 
+  def _child(self, widget: W) -> W:
+    """
+    Register a widget as a child. Lifecycle events (show/hide) propagate to registered children.
+    - If the widget is pushed onto the nav stack, do NOT register it (gui_app manages its lifecycle).
+    - If the widget is rendered inline in _render(), register it.
+    """
+    assert widget not in self._children, f"{type(widget).__name__} already a child of {type(self).__name__}"
+    self._children.append(widget)
+    return widget
+
+  _show_hide_depth = 0
+
   def show_event(self):
-    """Optionally handle show event. Parent must manually call this"""
-    # TODO: iterate through all child objects, check for subclassing from Widget/Layout (Scroller)
+    """Called when widget becomes visible. Propagates to registered children."""
+    if DEBUG:
+      print(f"{'  ' * Widget._show_hide_depth}show_event: {type(self).__name__}")
+      Widget._show_hide_depth += 1
+    for child in self._children:
+      child.show_event()
+    if DEBUG:
+      Widget._show_hide_depth -= 1
 
   def hide_event(self):
-    """Optionally handle hide event. Parent must manually call this"""
+    """Called when widget is hidden. Propagates to registered children."""
+    if DEBUG:
+      print(f"{'  ' * Widget._show_hide_depth}hide_event: {type(self).__name__}")
+      Widget._show_hide_depth += 1
+    for child in self._children:
+      child.hide_event()
+    if DEBUG:
+      Widget._show_hide_depth -= 1
 
   def dismiss(self, callback: Callable[[], None] | None = None):
     """Immediately dismiss the widget, firing the callback after."""

system/ui/widgets/nav_widget.py

@@ -69,7 +69,7 @@ class NavWidget(Widget, abc.ABC):
     self._shown_callback: Callable[[], None] | None = None  # transient callback fired after show animation completes
 
     # TODO: move this state into NavBar
-    self._nav_bar = NavBar()
+    self._nav_bar = self._child(NavBar())
     self._nav_bar_show_time = 0.0
     self._nav_bar_y_filter = FirstOrderFilter(0.0, 0.1, 1 / gui_app.target_fps)
 
@@ -214,7 +214,6 @@ class NavWidget(Widget, abc.ABC):
 
   def show_event(self):
     super().show_event()
-    self._nav_bar.show_event()
 
     # Reset state
     self._drag_start_pos = None

system/ui/widgets/scroller.py

@@ -422,18 +422,10 @@ class Scroller(Widget):
   """Wrapper for _Scroller so that children do not need to call events or pass down enabled for nav stack."""
   def __init__(self, **kwargs):
     super().__init__()
-    self._scroller = _Scroller([], **kwargs)
+    self._scroller = self._child(_Scroller([], **kwargs))
     # pass down enabled to child widget for nav stack
     self._scroller.set_enabled(lambda: self.enabled)
 
-  def show_event(self):
-    super().show_event()
-    self._scroller.show_event()
-
-  def hide_event(self):
-    super().hide_event()
-    self._scroller.hide_event()
-
   def _render(self, _):
     self._scroller.render(self._rect)