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feat(obj): add API to set/get object ID. (#6278)

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Signed-off-by: Neo Xu <neo.xu1990@gmail.com>
This commit is contained in:
Neo Xu
2024-06-13 05:39:59 +08:00
committed by GitHub
parent 864b54b851
commit cab55d8e5a
12 changed files with 163 additions and 22 deletions
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20
docs/others/obj_id.rst
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@@ -14,19 +14,20 @@ Usage
-----
Enable this feature by setting :c:macro:`LV_USE_OBJ_ID` to `1` in ``lv_conf.h``.
Use the builtin obj ID generator by setting :c:macro:`LV_USE_OBJ_ID_BUILTIN` to `1`.
Otherwise provide your own custom implementation.
The ID is automatically generated and assigned to :cpp:expr:`obj->id` during obj's
construction by calling API :cpp:expr:`lv_obj_assign_id(obj)` from :cpp:func:`lv_obj_constructor`.
Enable :c:macro:`LV_OBJ_ID_AUTO_ASSIGN` to automatically assign an ID to object when it's created.
It's done by calling function :cpp:func:`lv_obj_assign_id` from :cpp:func:`lv_obj_constructor`.
You can directly access the ID by :cpp:expr:`obj->id` or use API :cpp:expr:`lv_obj_stringify_id(obj, buf, len)`
You can either use your own ID generator by defining the function :cpp:func:`lv_obj_assign_id` or you can utilize the built-in one.
To use the builtin ID generator, set :c:macro:`LV_USE_OBJ_ID_BUILTIN` to `1`.
You can directly access the ID by :cpp:expr:`lv_obj_get_id(obj)` or use API :cpp:expr:`lv_obj_stringify_id(obj, buf, len)`
to get a string representation of the ID.
Use custom ID generator
~~~~~~~~~~~~~~~~~~~~~~~
Set :c:macro:`LV_USE_OBJ_ID_BUILTIN` to `0` in ``lv_conf.h``.
Set :c:macro:`LV_USE_OBJ_ID_BUILTIN` to `0` in ``lv_conf.h``.
Below APIs needed to be implemented and linked to lvgl.
@@ -35,6 +36,7 @@ Below APIs needed to be implemented and linked to lvgl.
void lv_obj_assign_id(const lv_obj_class_t * class_p, lv_obj_t * obj);
void lv_obj_free_id(lv_obj_t * obj);
const char * lv_obj_stringify_id(lv_obj_t * obj, char * buf, uint32_t len);
int lv_obj_id_compare(void * id1, void * id2);
:cpp:func:`lv_obj_assign_id` is called when an object is created. The object final class is passed from
@@ -55,3 +57,9 @@ This is useful to debug UI crash. From log we can rebuilt UI the moment before c
For example, if the obj is stored to a :cpp:expr:`timer->user_data`, but obj is deleted when timer expired.
Timer callback will crash because of accessing wild pointer.
From the dump log we can clearly see that the obj does not exist.
Find child by ID
~~~~~~~~~~~~~~~~
Use API :cpp:expr:`lv_obj_t * lv_obj_get_child_by_id(const lv_obj_t * obj, void * id);` to find a child by ID.
It will walk through all children and return the first child with the given ID.