[lvgl] Add refresh action to re-evaluate initial widget properties (#8675)

esphome/components/lvgl/__init__.py

@@ -18,13 +18,13 @@ from esphome.const import (
     CONF_TRIGGER_ID,
     CONF_TYPE,
 )
-from esphome.core import CORE, ID
+from esphome.core import CORE, ID, Lambda
 from esphome.cpp_generator import MockObj
 from esphome.final_validate import full_config
 from esphome.helpers import write_file_if_changed
 
 from . import defines as df, helpers, lv_validation as lvalid
-from .automation import disp_update, focused_widgets, update_to_code
+from .automation import disp_update, focused_widgets, refreshed_widgets, update_to_code
 from .defines import add_define
 from .encoders import (
     ENCODERS_CONFIG,
@@ -240,6 +240,13 @@ def final_validation(configs):
                     "A non adjustable arc may not be focused",
                     path,
                 )
+        for w in refreshed_widgets:
+            path = global_config.get_path_for_id(w)
+            widget_conf = global_config.get_config_for_path(path[:-1])
+            if not any(isinstance(v, Lambda) for v in widget_conf.values()):
+                raise cv.Invalid(
+                    f"Widget '{w}' does not have any templated properties to refresh",
+                )
 
 
 async def to_code(configs):

esphome/components/lvgl/automation.py

@@ -35,7 +35,13 @@ from .lvcode import (
     lv_obj,
     lvgl_comp,
 )
-from .schemas import DISP_BG_SCHEMA, LIST_ACTION_SCHEMA, LVGL_SCHEMA, base_update_schema
+from .schemas import (
+    ALL_STYLES,
+    DISP_BG_SCHEMA,
+    LIST_ACTION_SCHEMA,
+    LVGL_SCHEMA,
+    base_update_schema,
+)
 from .types import (
     LV_STATE,
     LvglAction,
@@ -57,6 +63,7 @@ from .widgets import (
 
 # Record widgets that are used in a focused action here
 focused_widgets = set()
+refreshed_widgets = set()
 
 
 async def action_to_code(
@@ -361,3 +368,45 @@ async def obj_update_to_code(config, action_id, template_arg, args):
     return await action_to_code(
         widgets, do_update, action_id, template_arg, args, config
     )
+
+
+def validate_refresh_config(config):
+    for w in config:
+        refreshed_widgets.add(w[CONF_ID])
+    return config
+
+
+@automation.register_action(
+    "lvgl.widget.refresh",
+    ObjUpdateAction,
+    cv.All(
+        cv.ensure_list(
+            cv.maybe_simple_value(
+                {
+                    cv.Required(CONF_ID): cv.use_id(lv_obj_t),
+                },
+                key=CONF_ID,
+            )
+        ),
+        validate_refresh_config,
+    ),
+)
+async def obj_refresh_to_code(config, action_id, template_arg, args):
+    widget = await get_widgets(config)
+
+    async def do_refresh(widget: Widget):
+        # only update style properties that might have changed, i.e. are templated
+        config = {k: v for k, v in widget.config.items() if isinstance(v, Lambda)}
+        await set_obj_properties(widget, config)
+        # must pass all widget-specific options here, even if not templated, but only do so if at least one is
+        # templated. First filter out common style properties.
+        config = {k: v for k, v in widget.config.items() if k not in ALL_STYLES}
+        if any(isinstance(v, Lambda) for v in config.values()):
+            await widget.type.to_code(widget, config)
+            if (
+                widget.type.w_type.value_property is not None
+                and widget.type.w_type.value_property in config
+            ):
+                lv.event_send(widget.obj, UPDATE_EVENT, nullptr)
+
+    return await action_to_code(widget, do_refresh, action_id, template_arg, args)

tests/components/lvgl/lvgl-package.yaml

@@ -212,7 +212,7 @@ lvgl:
         - animimg:
             height: 60
             id: anim_img
-            src: [cat_image, dog_image]
+            src: !lambda "return {dog_image, cat_image};"
             repeat_count: 10
             duration: 1s
             auto_start: true
@@ -224,6 +224,7 @@ lvgl:
                   id: anim_img
                   src: !lambda "return {dog_image, cat_image};"
                   duration: 2s
+              - lvgl.widget.refresh: anim_img
         - label:
             on_boot:
               lvgl.label.update: