lv_obj_event.h

Enums

enum lv_cover_res_t

Cover check results.

Values:

enumerator LV_COVER_RES_COVER
enumerator LV_COVER_RES_NOT_COVER
enumerator LV_COVER_RES_MASKED

Functions

lv_result_t lv_obj_send_event(struct _lv_obj_t *obj, lv_event_code_t event_code, void *param)

Send an event to the object

Parameters:

  • obj -- pointer to an object

  • event_code -- the type of the event from lv_event_t

  • param -- arbitrary data depending on the widget type and the event. (Usually NULL)

Returns:

LV_RESULT_OK: obj was not deleted in the event; LV_RESULT_INVALID: obj was deleted in the event_code

lv_result_t lv_obj_event_base(const struct _lv_obj_class_t *class_p, lv_event_t *e)

Used by the widgets internally to call the ancestor widget types's event handler

Parameters:

  • class_p -- pointer to the class of the widget (NOT the ancestor class)

  • e -- pointer to the event descriptor

Returns:

LV_RESULT_OK: the target object was not deleted in the event; LV_RESULT_INVALID: it was deleted in the event_code

struct _lv_obj_t *lv_event_get_current_target_obj(lv_event_t *e)

Get the current target of the event. It's the object which event handler being called. If the event is not bubbled it's the same as "original" target.

Parameters:

e -- pointer to the event descriptor

Returns:

the target of the event_code

struct _lv_obj_t *lv_event_get_target_obj(lv_event_t *e)

Get the object originally targeted by the event. It's the same even if the event is bubbled.

Parameters:

e -- pointer to the event descriptor

Returns:

pointer to the original target of the event_code

void lv_obj_add_event(struct _lv_obj_t *obj, lv_event_cb_t event_cb, lv_event_code_t filter, void *user_data)

Add an event handler function for an object. Used by the user to react on event which happens with the object. An object can have multiple event handler. They will be called in the same order as they were added.

Parameters:

  • obj -- pointer to an object

  • filter -- and event code (e.g. LV_EVENT_CLICKED) on which the event should be called. LV_EVENT_ALL can be sued the receive all the events.

  • event_cb -- the new event function

  • user_data -- custom data data will be available in event_cb

uint32_t lv_obj_get_event_count(struct _lv_obj_t *obj)
lv_event_dsc_t *lv_obj_get_event_dsc(struct _lv_obj_t *obj, uint32_t index)
bool lv_obj_remove_event(struct _lv_obj_t *obj, uint32_t index)
bool lv_obj_remove_event_cb(struct _lv_obj_t *obj, lv_event_cb_t event_cb)
lv_indev_t *lv_event_get_indev(lv_event_t *e)

Get the input device passed as parameter to indev related events.

Parameters:

e -- pointer to an event

Returns:

the indev that triggered the event or NULL if called on a not indev related event

lv_layer_t *lv_event_get_layer(lv_event_t *e)

Get the draw context which should be the first parameter of the draw functions. Namely: LV_EVENT_DRAW_MAIN/POST, LV_EVENT_DRAW_MAIN/POST_BEGIN, LV_EVENT_DRAW_MAIN/POST_END

Parameters:

e -- pointer to an event

Returns:

pointer to a draw context or NULL if called on an unrelated event

const lv_area_t *lv_event_get_old_size(lv_event_t *e)

Get the old area of the object before its size was changed. Can be used in LV_EVENT_SIZE_CHANGED

Parameters:

e -- pointer to an event

Returns:

the old absolute area of the object or NULL if called on an unrelated event

uint32_t lv_event_get_key(lv_event_t *e)

Get the key passed as parameter to an event. Can be used in LV_EVENT_KEY

Parameters:

e -- pointer to an event

Returns:

the triggering key or NULL if called on an unrelated event

lv_anim_t *lv_event_get_scroll_anim(lv_event_t *e)

Get the animation descriptor of a scrolling. Can be used in LV_EVENT_SCROLL_BEGIN

Parameters:

e -- pointer to an event

Returns:

the animation that will scroll the object. (can be modified as required)

void lv_event_set_ext_draw_size(lv_event_t *e, lv_coord_t size)

Set the new extra draw size. Can be used in LV_EVENT_REFR_EXT_DRAW_SIZE

Parameters:

  • e -- pointer to an event

  • size -- The new extra draw size

lv_point_t *lv_event_get_self_size_info(lv_event_t *e)

Get a pointer to an lv_point_t variable in which the self size should be saved (width in point->x and height point->y). Can be used in LV_EVENT_GET_SELF_SIZE

Parameters:

e -- pointer to an event

Returns:

pointer to lv_point_t or NULL if called on an unrelated event

lv_hit_test_info_t *lv_event_get_hit_test_info(lv_event_t *e)

Get a pointer to an lv_hit_test_info_t variable in which the hit test result should be saved. Can be used in LV_EVENT_HIT_TEST

Parameters:

e -- pointer to an event

Returns:

pointer to lv_hit_test_info_t or NULL if called on an unrelated event

const lv_area_t *lv_event_get_cover_area(lv_event_t *e)

Get a pointer to an area which should be examined whether the object fully covers it or not. Can be used in LV_EVENT_HIT_TEST

Parameters:

e -- pointer to an event

Returns:

an area with absolute coordinates to check

void lv_event_set_cover_res(lv_event_t *e, lv_cover_res_t res)

Set the result of cover checking. Can be used in LV_EVENT_COVER_CHECK

Parameters:
lv_draw_task_t *lv_event_get_draw_task(lv_event_t *e)

Get the draw task which was just added. Can be used in LV_EVENT_DRAW_TASK_ADDED event

Parameters:

e -- pointer to an event

Returns:

the added draw task

struct lv_hit_test_info_t
#include <lv_obj_event.h>

Used as the event parameter of LV_EVENT_HIT_TEST to check if an point can click the object or not. res should be set like this:

  • If already set to false an other event wants that point non clickable. If you want to respect it leave it as false or set true to overwrite it.

  • If already set true and point shouldn't be clickable set to false

  • If already set to true you agree that point can click the object leave it as true

Public Members

const lv_point_t *point

A point relative to screen to check if it can click the object or not

bool res

true: point can click the object; false: it cannot

struct lv_cover_check_info_t
#include <lv_obj_event.h>

Used as the event parameter of LV_EVENT_COVER_CHECK to check if an area is covered by the object or not. In the event use const lv_area_t * area = lv_event_get_cover_area(e) to get the area to check and lv_event_set_cover_res(e, res) to set the result.

Public Members

lv_cover_res_t res
const lv_area_t *area