# lv_obj_property.h (/api/core/lv_obj_property_h)
Functions [#functions]
lv_obj_set_property [#lv_obj_set_property]
Set Widget property.
```c title=" " lineNumbers=1
lv_result_t lv_obj_set_property(lv_obj_t *obj, const lv_property_t *value)
```
Parameters
| Name | Type | Description |
| ------- | ---------------------------------------------------------------- | --------------------- |
| `obj` | | pointer to Widget |
| `value` | | property value to set |
**Returns:** — return LV\_RESULT\_OK if call succeeded
lv_obj_set_properties [#lv_obj_set_properties]
Set multiple Widget properties. Helper `LV_OBJ_SET_PROPERTY_ARRAY` can be used for constant property array.
```c title=" " lineNumbers=1
lv_result_t lv_obj_set_properties(lv_obj_t *obj, const lv_property_t *value, uint32_t count)
```
Parameters
| Name | Type | Description |
| ------- | ---------------------------------------------------------------- | --------------------------- |
| `obj` | | pointer to Widget |
| `value` | | property value array to set |
| `count` | | number of array elements |
**Returns:** — return LV\_RESULT\_OK if call succeeded
lv_obj_get_property [#lv_obj_get_property]
Read property value from Widget. If id is a style property, computes the style of PART\_MAIN.
```c title=" " lineNumbers=1
lv_property_t lv_obj_get_property(lv_obj_t *obj, lv_prop_id_t id)
```
Parameters
| Name | Type | Description |
| ----- | ------------------------------------------------ | ---------------------- |
| `obj` | | pointer to Widget |
| `id` | | ID of property to read |
**Returns:** — return property value read. The returned property ID is set to `LV_PROPERTY_ID_INVALID` if read failed.
lv_obj_get_style_property [#lv_obj_get_style_property]
Read style property value from Widget
```c title=" " lineNumbers=1
lv_property_t lv_obj_get_style_property(lv_obj_t *obj, lv_prop_id_t id, lv_part_t part)
```
Parameters
| Name | Type | Description |
| ------ | ------------------------------------------------ | ---------------------------------------------------- |
| `obj` | | pointer to Widget |
| `id` | | ID of style property |
| `part` | | part for which the style property should be computed |
**Returns:** — return property value read. The returned property ID is set to `LV_PROPERTY_ID_INVALID` if read failed.
lv_obj_property_get_id [#lv_obj_property_get_id]
Get property ID by recursively searching for name in Widget's class hierarchy, and if still not found, then search style properties. Requires to enabling `LV_USE_OBJ_PROPERTY_NAME`.
```c title=" " lineNumbers=1
lv_prop_id_t lv_obj_property_get_id(const lv_obj_t *obj, const char *name)
```
Parameters
| Name | Type | Description |
| ------ | ------------------------------------------------------ | -------------------------------------------------------------------------- |
| `obj` | | pointer to Widget whose class and base-class hierarchy are to be searched. |
| `name` | `const char *` | property name |
**Returns:** — property ID found or `LV_PROPERTY_ID_INVALID` if not found.
lv_obj_class_property_get_id [#lv_obj_class_property_get_id]
Get property ID by doing a non-recursive search for name directly in Widget class properties. Requires enabling `LV_USE_OBJ_PROPERTY_NAME`.
```c title=" " lineNumbers=1
lv_prop_id_t lv_obj_class_property_get_id(const lv_obj_class_t *clz, const char *name)
```
Parameters
| Name | Type | Description |
| ------ | ------------------------------------------------------------------ | ---------------------------------------------------- |
| `clz` | | pointer to Widget class that has specified property. |
| `name` | `const char *` | property name |
**Returns:** — property ID found or `LV_PROPERTY_ID_INVALID` if not found.
lv_style_property_get_id [#lv_style_property_get_id]
Get style property ID by name. Requires enabling `LV_USE_OBJ_PROPERTY_NAME`.
```c title=" " lineNumbers=1
lv_prop_id_t lv_style_property_get_id(const char *name)
```
Parameters
| Name | Type | Description |
| ------ | -------------- | ------------- |
| `name` | `const char *` | property name |
**Returns:** — property ID found or `LV_PROPERTY_ID_INVALID` if not found.
Enums [#enums]
\_lv_prop_id_range_boundary_t [#_lv_prop_id_range_boundary_t]
Group of predefined widget ID start value.
| Name | Value |
| -------------------------------- | ------------ |
| `LV_PROPERTY_ID_INVALID` | `0` |
| `LV_PROPERTY_STYLE_START` | `0x00` |
| `LV_PROPERTY_ID_START` | `0x0100` |
| `LV_PROPERTY_OBJ_START` | `0x0100` |
| `LV_PROPERTY_IMAGE_START` | `0x0200` |
| `LV_PROPERTY_LABEL_START` | `0x0300` |
| `LV_PROPERTY_KEYBOARD_START` | `0x0400` |
| `LV_PROPERTY_TEXTAREA_START` | `0x0500` |
| `LV_PROPERTY_ROLLER_START` | `0x0600` |
| `LV_PROPERTY_DROPDOWN_START` | `0x0700` |
| `LV_PROPERTY_SLIDER_START` | `0x0800` |
| `LV_PROPERTY_ANIMIMAGE_START` | `0x0900` |
| `LV_PROPERTY_ARC_START` | `0x0a00` |
| `LV_PROPERTY_BAR_START` | `0x0b00` |
| `LV_PROPERTY_SWITCH_START` | `0x0c00` |
| `LV_PROPERTY_CHECKBOX_START` | `0x0d00` |
| `LV_PROPERTY_LED_START` | `0x0e00` |
| `LV_PROPERTY_LINE_START` | `0x0f00` |
| `LV_PROPERTY_SCALE_START` | `0x1000` |
| `LV_PROPERTY_SPINBOX_START` | `0x1100` |
| `LV_PROPERTY_SPINNER_START` | `0x1200` |
| `LV_PROPERTY_TABLE_START` | `0x1300` |
| `LV_PROPERTY_TABVIEW_START` | `0x1400` |
| `LV_PROPERTY_BUTTONMATRIX_START` | `0x1500` |
| `LV_PROPERTY_SPAN_START` | `0x1600` |
| `LV_PROPERTY_MENU_START` | `0x1700` |
| `LV_PROPERTY_CHART_START` | `0x1800` |
| `LV_PROPERTY_ID_BUILTIN_LAST` | `0xffff` |
| `LV_PROPERTY_ID_ANY` | `0x7ffffffe` |
Structs [#structs]
\_lv_property_name_t [#_lv_property_name_t]
| Member | Type | Description |
| ------ | ------------------------------- | ----------- |
| `name` | `const char *` | |
| `id` | | |
lv_property_t [#lv_property_t]
| Member | Type | Description |
| ---------- | -------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `id` | | |
| `num` | | Signed integer number (enums or "normal" numbers) |
| `num_u` | | Unsigned integer number (opacity, Booleans) \
|
| `enable` | | Booleans |
| `ptr` | `const void *` | Constant pointers (font, cone text, etc.) |
| `color` | | Colors |
| `precise` | | float or int for precise value |
| `point` | | Point, contains two int32\_t |
| `style` | | Note that place struct member `style` at first place is intended. `style` shares same memory with `num`, `ptr`, `color`. So we set the style value directly without using `prop.style.num`.
E.g.
static const obj\_pos\_x = \{ .id = LV\_PROPERTY\_STYLE\_X, .num = 123, .selector = LV\_STATE\_PRESSED, }
instead of: static const obj\_pos\_x = \{ .id = LV\_PROPERTY\_STYLE\_X, .style.num = 123, // note this line. .selector = LV\_STATE\_PRESSED, } Make sure it's the first element in struct. |
| `selector` | | Style selector, lv\_part\_t \| lv\_state\_t |
| `arg1` | | |
| `arg2` | | |
| \`\` | | |
* `lv_obj_set_property` — param `value`
* `lv_obj_set_properties` — param `value`
lv_property_ops_t [#lv_property_ops_t]
| Member | Type | Description |
| -------- | ------------------------------- | ------------------------------ |
| `id` | | |
| `setter` | `void *` | Callback used to set property. |
| `getter` | `void *` | Callback used to get property. |
Macros [#macros]
LV_PROPERTY_TYPE_INVALID [#lv_property_type_invalid]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_INVALID 0 /*Use default 0 as invalid to detect program outliers*/
```
LV_PROPERTY_TYPE_INT [#lv_property_type_int]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_INT 1 /*int32_t type*/
```
LV_PROPERTY_TYPE_PRECISE [#lv_property_type_precise]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_PRECISE 2 /*lv_value_precise_t, int32_t or float depending on LV_USE_FLOAT*/
```
LV_PROPERTY_TYPE_COLOR [#lv_property_type_color]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_COLOR 3 /*ARGB8888 type*/
```
LV_PROPERTY_TYPE_POINT [#lv_property_type_point]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_POINT 4 /*lv_point_t */
```
LV_PROPERTY_TYPE_POINTER [#lv_property_type_pointer]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_POINTER 5 /*void * pointer*/
```
LV_PROPERTY_TYPE_IMGSRC [#lv_property_type_imgsrc]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_IMGSRC 6 /*Special pointer for image*/
```
LV_PROPERTY_TYPE_TEXT [#lv_property_type_text]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_TEXT 7 /*Special pointer of char* */
```
LV_PROPERTY_TYPE_OBJ [#lv_property_type_obj]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_OBJ 8 /*Special pointer of lv_obj_t* */
```
LV_PROPERTY_TYPE_DISPLAY [#lv_property_type_display]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_DISPLAY 9 /*Special pointer of lv_display_t* */
```
LV_PROPERTY_TYPE_FONT [#lv_property_type_font]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_FONT 10 /*Special pointer of lv_font_t* */
```
LV_PROPERTY_TYPE_BOOL [#lv_property_type_bool]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_BOOL 11 /*int32_t type*/
```
LV_PROPERTY_TYPE_SHIFT [#lv_property_type_shift]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE_SHIFT 28
```
LV_PROPERTY_TYPE2_SHIFT [#lv_property_type2_shift]
```c title=" " lineNumbers=1
#define LV_PROPERTY_TYPE2_SHIFT 24
```
LV_PROPERTY_ID [#lv_property_id]
```c title=" " lineNumbers=1
#define LV_PROPERTY_ID(clz, name, type, index) \
LV_PROPERTY_## clz ##_##name = (LV_PROPERTY_## clz ##_START + ((int)index)) | ((type) << LV_PROPERTY_TYPE_SHIFT)
```
LV_PROPERTY_ID2 [#lv_property_id2]
```c title=" " lineNumbers=1
#define LV_PROPERTY_ID2(clz, name, type, type2, index) \
LV_PROPERTY_ID(clz, name, type, index) | ((type2) << LV_PROPERTY_TYPE2_SHIFT)
```
LV_PROPERTY_ID_TYPE [#lv_property_id_type]
```c title=" " lineNumbers=1
#define LV_PROPERTY_ID_TYPE(id) \
((id) >> LV_PROPERTY_TYPE_SHIFT)
```
LV_PROPERTY_ID_TYPE2 [#lv_property_id_type2]
```c title=" " lineNumbers=1
#define LV_PROPERTY_ID_TYPE2(id) \
((id) >> LV_PROPERTY_TYPE_SHIFT)
```
LV_PROPERTY_ID_INDEX [#lv_property_id_index]
```c title=" " lineNumbers=1
#define LV_PROPERTY_ID_INDEX(id) \
((id) & 0xfffffff)
```
LV_OBJ_SET_PROPERTY_ARRAY [#lv_obj_set_property_array]
```c title=" " lineNumbers=1
#define LV_OBJ_SET_PROPERTY_ARRAY(obj, array) \
lv_obj_set_properties(obj, array, LV_ARRAYLEN(array))
```
LV_PROPERTY_CLASS_FIELDS [#lv_property_class_fields]
```c title=" " lineNumbers=1
#define LV_PROPERTY_CLASS_FIELDS(widget, uppercase) \
.prop_index_start = LV_PROPERTY_##uppercase##_START, \
.prop_index_end = LV_PROPERTY_##uppercase##_END, \
.properties = lv_##widget##_properties, \
.properties_count = LV_ARRAYLEN(lv_##widget##_properties), \
.property_names = lv_##widget##_property_names, \
.names_count = LV_ARRAYLEN(lv_##widget##_property_names)
```
Dependencies [#dependencies]