lv_event.h

Typedefs

typedef void (*lv_event_cb_t)(lv_event_t *e)

Enums

enum lv_event_code_t

Type of event being sent to Widget

Values:

enumerator LV_EVENT_ALL

enumerator LV_EVENT_PRESSED

Input device events Widget has been pressed

enumerator LV_EVENT_PRESSING

Widget is being pressed (sent continuously while pressing)

enumerator LV_EVENT_PRESS_LOST

Widget is still being pressed but slid cursor/finger off Widget

enumerator LV_EVENT_SHORT_CLICKED

Widget was pressed for a short period of time, then released. Not sent if scrolled.

enumerator LV_EVENT_SINGLE_CLICKED

Sent for first short click within a small distance and short time

enumerator LV_EVENT_DOUBLE_CLICKED

Sent for second short click within small distance and short time

enumerator LV_EVENT_TRIPLE_CLICKED

Sent for third short click within small distance and short time

enumerator LV_EVENT_LONG_PRESSED

Object has been pressed for at least long_press_time. Not sent if scrolled.

enumerator LV_EVENT_LONG_PRESSED_REPEAT

Sent after long_press_time in every long_press_repeat_time ms. Not sent if scrolled.

enumerator LV_EVENT_CLICKED

Sent on release if not scrolled (regardless to long press)

enumerator LV_EVENT_RELEASED

Sent in every cases when Widget has been released

enumerator LV_EVENT_SCROLL_BEGIN

Scrolling begins. The event parameter is a pointer to the animation of the scroll. Can be modified

enumerator LV_EVENT_SCROLL_THROW_BEGIN

enumerator LV_EVENT_SCROLL_END

Scrolling ends

enumerator LV_EVENT_SCROLL

Scrolling

enumerator LV_EVENT_GESTURE

A gesture is detected. Get gesture with lv_indev_get_gesture_dir(lv_indev_active());

enumerator LV_EVENT_KEY

A key is sent to Widget. Get key with lv_indev_get_key(lv_indev_active());

enumerator LV_EVENT_ROTARY

An encoder or wheel was rotated. Get rotation count with lv_event_get_rotary_diff(e);

enumerator LV_EVENT_FOCUSED

Widget received focus

enumerator LV_EVENT_DEFOCUSED

Widget's focus has been lost

enumerator LV_EVENT_LEAVE

Widget's focus has been lost but is still selected

enumerator LV_EVENT_HIT_TEST

Perform advanced hit-testing

enumerator LV_EVENT_INDEV_RESET

Indev has been reset

enumerator LV_EVENT_HOVER_OVER

Indev hover over object

enumerator LV_EVENT_HOVER_LEAVE

Indev hover leave object

enumerator LV_EVENT_COVER_CHECK

Drawing events Check if Widget fully covers an area. The event parameter is lv_cover_check_info_t *.

enumerator LV_EVENT_REFR_EXT_DRAW_SIZE

Get required extra draw area around Widget (e.g. for shadow). The event parameter is int32_t * to store the size.

enumerator LV_EVENT_DRAW_MAIN_BEGIN

Starting the main drawing phase

enumerator LV_EVENT_DRAW_MAIN

Perform the main drawing

enumerator LV_EVENT_DRAW_MAIN_END

Finishing the main drawing phase

enumerator LV_EVENT_DRAW_POST_BEGIN

Starting the post draw phase (when all children are drawn)

enumerator LV_EVENT_DRAW_POST

Perform the post draw phase (when all children are drawn)

enumerator LV_EVENT_DRAW_POST_END

Finishing the post draw phase (when all children are drawn)

enumerator LV_EVENT_DRAW_TASK_ADDED

Adding a draw task. The LV_OBJ_FLAG_SEND_DRAW_TASK_EVENTS flag needs to be set

enumerator LV_EVENT_VALUE_CHANGED

Special events Widget's value has changed (i.e. slider moved)

enumerator LV_EVENT_INSERT

Text has been inserted into Widget. The event data is char * being inserted.

enumerator LV_EVENT_REFRESH

Notify Widget to refresh something on it (for user)

enumerator LV_EVENT_READY

A process has finished

enumerator LV_EVENT_CANCEL

A process has been cancelled

enumerator LV_EVENT_STATE_CHANGED

The state of the widget changed

enumerator LV_EVENT_CREATE

Other events Object is being created

enumerator LV_EVENT_DELETE

Object is being deleted

enumerator LV_EVENT_CHILD_CHANGED

Child was removed, added, or its size, position were changed

enumerator LV_EVENT_CHILD_CREATED

Child was created, always bubbles up to all parents

enumerator LV_EVENT_CHILD_DELETED

Child was deleted, always bubbles up to all parents

enumerator LV_EVENT_SCREEN_UNLOAD_START

A screen unload started, fired immediately when scr_load is called

enumerator LV_EVENT_SCREEN_LOAD_START

A screen load started, fired when the screen change delay is expired

enumerator LV_EVENT_SCREEN_LOADED

A screen was loaded

enumerator LV_EVENT_SCREEN_UNLOADED

A screen was unloaded

enumerator LV_EVENT_SIZE_CHANGED

Object coordinates/size have changed

enumerator LV_EVENT_STYLE_CHANGED

Object's style has changed

enumerator LV_EVENT_LAYOUT_CHANGED

A child's position position has changed due to a layout recalculation

enumerator LV_EVENT_GET_SELF_SIZE

Get internal size of a widget

enumerator LV_EVENT_INVALIDATE_AREA

Events of optional LVGL components An area is invalidated (marked for redraw). lv_event_get_param(e) returns a pointer to an lv_area_t object with the coordinates of the area to be invalidated. The area can be freely modified if needed to adapt it a special requirement of the display. Usually needed with monochrome displays to invalidate N x 8 rows or columns in one pass.

enumerator LV_EVENT_RESOLUTION_CHANGED

Sent when the resolution changes due to lv_display_set_resolution() or lv_display_set_rotation().

enumerator LV_EVENT_COLOR_FORMAT_CHANGED

Sent as a result of any call to lv_display_set_color_format().

enumerator LV_EVENT_REFR_REQUEST

Sent when something happened that requires redraw.

enumerator LV_EVENT_REFR_START

Sent before a refreshing cycle starts. Sent even if there is nothing to redraw.

enumerator LV_EVENT_REFR_READY

Sent when refreshing has been completed (after rendering and calling flush callback). Sent even if no redraw happened.

enumerator LV_EVENT_RENDER_START

Sent just before rendering begins.

enumerator LV_EVENT_RENDER_READY

Sent after rendering has been completed.

enumerator LV_EVENT_FLUSH_START

Sent before flush callback is called.

enumerator LV_EVENT_FLUSH_FINISH

Sent after flush callback call has returned.

enumerator LV_EVENT_FLUSH_WAIT_START

Sent before flush wait callback is called.

enumerator LV_EVENT_FLUSH_WAIT_FINISH

Sent after flush wait callback call has returned.

enumerator LV_EVENT_UPDATE_LAYOUT_COMPLETED

Sent after layout update completes

enumerator LV_EVENT_VSYNC

enumerator LV_EVENT_VSYNC_REQUEST

enumerator LV_EVENT_TRANSLATION_LANGUAGE_CHANGED

Sent when the translation language changed.

enumerator LV_EVENT_LAST

enumerator LV_EVENT_PREPROCESS

Number of default events

enumerator LV_EVENT_MARKED_DELETING

This is a flag that can be set with an event so it's processed before the class default event processing

Functions

lv_result_t lv_event_send(lv_event_list_t *list, lv_event_t *e, bool preprocess)

Event callback. Events are used to notify the user of some action being taken on Widget. For details, see lv_event_t.

lv_event_dsc_t *lv_event_add(lv_event_list_t *list, lv_event_cb_t cb, lv_event_code_t filter, void *user_data)

bool lv_event_remove_dsc(lv_event_list_t *list, lv_event_dsc_t *dsc)

uint32_t lv_event_get_count(lv_event_list_t *list)

lv_event_dsc_t *lv_event_get_dsc(lv_event_list_t *list, uint32_t index)

lv_event_cb_t lv_event_dsc_get_cb(lv_event_dsc_t *dsc)

void *lv_event_dsc_get_user_data(lv_event_dsc_t *dsc)

bool lv_event_remove(lv_event_list_t *list, uint32_t index)

void lv_event_remove_all(lv_event_list_t *list)

void *lv_event_get_target(lv_event_t *e)

Get Widget originally targeted by the event. It's the same even if event was bubbled.

Parameters:

e – pointer to the event descriptor

Returns:

the target of the event_code

void *lv_event_get_current_target(lv_event_t *e)

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

Parameters:

e – pointer to the event descriptor

Returns:

pointer to the current target of the event_code

lv_event_code_t lv_event_get_code(lv_event_t *e)

Get event code of an event.

Parameters:

e – pointer to the event descriptor

Returns:

the event code. (E.g. LV_EVENT_CLICKED, LV_EVENT_FOCUSED, etc)

void *lv_event_get_param(lv_event_t *e)

Get parameter passed when event was sent.

Parameters:

e – pointer to the event descriptor

Returns:

pointer to the parameter

void *lv_event_get_user_data(lv_event_t *e)

Get user_data passed when event was registered on Widget.

Parameters:

e – pointer to the event descriptor

Returns:

pointer to the user_data

void lv_event_stop_bubbling(lv_event_t *e)

Stop event from bubbling. This is only valid when called in the middle of an event processing chain.

Parameters:

e – pointer to the event descriptor

void lv_event_stop_trickling(lv_event_t *e)

Stop event from trickling down to children. This is only valid when called in the middle of an event processing chain.

Parameters:

e – pointer to the event descriptor

void lv_event_stop_processing(lv_event_t *e)

Stop processing this event. This is only valid when called in the middle of an event processing chain.

Parameters:

e – pointer to the event descriptor

void lv_event_free_user_data_cb(lv_event_t *e)

Helper function typically used in LV_EVENT_DELETE to free the event's user_data

Parameters:

e – pointer to an event descriptor

uint32_t lv_event_register_id(void)

Register a new, custom event ID. It can be used the same way as e.g. LV_EVENT_CLICKED

to send custom events

Example:

uint32_t LV_EVENT_MINE = 0;
...
e = lv_event_register_id();
...
lv_obj_send_event(obj, LV_EVENT_MINE, &some_data);

Returns:

the new event id

const char *lv_event_code_get_name(lv_event_code_t code)

Get the name of an event code.

Parameters:

code – the event code

Returns:

the name of the event code as a string

void lv_event_desc_set_external_data(lv_event_dsc_t *dsc, void *data, void (*free_cb)(void *data))

Set external data and its destructor for an event descriptor. This allows associating custom data with an event callback that will be automatically cleaned up when the event descriptor is removed or destroyed.

Parameters:

• dsc – pointer to an event descriptor (from lv_obj_add_event_cb)

• data – pointer to the external data to associate with the event descriptor

• free_cb – function pointer to a destructor that will be called to clean up the external data. The destructor will receive the data pointer as its parameter.

struct lv_event_list_t

Public Members

lv_array_t array

uint8_t is_traversing

True: the list is being nested traversed

uint8_t has_marked_deleting

True: the list has marked deleting objects when some of events are marked as deleting