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[lvgl events] event code

2022-07-28 14:03:00 【Like warm know cold】

Click on 、 slide 、 Input 、 Changes in numbers and so on can trigger events . Events are responses to different operations .

Recently I saw the configuration screen , This thing seems to be quite simple to develop ！！ Ha ha ha ！！ End of study LVGL Take a look at this .

【LVGL(4)】 Object events and event bubbles _ Like warm know cold blog Object events and event bubbles , The event of an object is that different events call different function implementation codes ~https://blog.csdn.net/qq_41650023/article/details/125260000

【LVGL event (Events)】 Event code _ Like warm know cold blog LVGL Event code introduction of https://blog.csdn.net/qq_41650023/article/details/125991887

【LVGL event (Events)】 Application of events on different components （ One ）_ Like warm know cold blog arc 、 slider 、 Check box 、 Drop down list to read its value API.https://blog.csdn.net/qq_41650023/article/details/125981209

First statement ： This article is for your reference ！ There will inevitably be negligence ！

Event code

Officials divided the incident into several groups ：

Input device events（ input device ）
Drawing events（ mapping ）
Other events（ other ）
Special events（ special ）
Custom events（ User customization ）

All objects (such as Buttons/Labels/Sliders etc.) regardless their type receive the Input device, Drawing and Other events.
All objects （ Button 、 label 、 Slider, etc ） Will receive Input device、Drawing、Other event .
However, the Special events are specific to a particular widget type.
Special events are used for specific widgets .

The source code of the event

route ：lvgl\src\core\lv_event.h

/**
 * Type of event being sent to the object.
 */
typedef enum {
    LV_EVENT_ALL = 0,

    /** Input device events*/
    LV_EVENT_PRESSED,             /**< The object has been pressed*/
    LV_EVENT_PRESSING,            /**< The object is being pressed (called continuously while pressing)*/
    LV_EVENT_PRESS_LOST,          /**< The object is still being pressed but slid cursor/finger off of the object */
    LV_EVENT_SHORT_CLICKED,       /**< The object was pressed for a short period of time, then released it. Not called if scrolled.*/
    LV_EVENT_LONG_PRESSED,        /**< Object has been pressed for at least `long_press_time`.  Not called if scrolled.*/
    LV_EVENT_LONG_PRESSED_REPEAT, /**< Called after `long_press_time` in every `long_press_repeat_time` ms.  Not called if scrolled.*/
    LV_EVENT_CLICKED,             /**< Called on release if not scrolled (regardless to long press)*/
    LV_EVENT_RELEASED,            /**< Called in every cases when the object has been released*/
    LV_EVENT_SCROLL_BEGIN,        /**< Scrolling begins. The event parameter is a pointer to the animation of the scroll. Can be modified*/
    LV_EVENT_SCROLL_END,          /**< Scrolling ends*/
    LV_EVENT_SCROLL,              /**< Scrolling*/
    LV_EVENT_GESTURE,             /**< A gesture is detected. Get the gesture with `lv_indev_get_gesture_dir(lv_indev_get_act());` */
    LV_EVENT_KEY,                 /**< A key is sent to the object. Get the key with `lv_indev_get_key(lv_indev_get_act());`*/
    LV_EVENT_FOCUSED,             /**< The object is focused*/
    LV_EVENT_DEFOCUSED,           /**< The object is defocused*/
    LV_EVENT_LEAVE,               /**< The object is defocused but still selected*/
    LV_EVENT_HIT_TEST,            /**< Perform advanced hit-testing*/

    /** Drawing events*/
    LV_EVENT_COVER_CHECK,        /**< Check if the object fully covers an area. The event parameter is `lv_cover_check_info_t *`.*/
    LV_EVENT_REFR_EXT_DRAW_SIZE, /**< Get the required extra draw area around the object (e.g. for shadow). The event parameter is `lv_coord_t *` to store the size.*/
    LV_EVENT_DRAW_MAIN_BEGIN,    /**< Starting the main drawing phase*/
    LV_EVENT_DRAW_MAIN,          /**< Perform the main drawing*/
    LV_EVENT_DRAW_MAIN_END,      /**< Finishing the main drawing phase*/
    LV_EVENT_DRAW_POST_BEGIN,    /**< Starting the post draw phase (when all children are drawn)*/
    LV_EVENT_DRAW_POST,          /**< Perform the post draw phase (when all children are drawn)*/
    LV_EVENT_DRAW_POST_END,      /**< Finishing the post draw phase (when all children are drawn)*/
    LV_EVENT_DRAW_PART_BEGIN,    /**< Starting to draw a part. The event parameter is `lv_obj_draw_dsc_t *`. */
    LV_EVENT_DRAW_PART_END,      /**< Finishing to draw a part. The event parameter is `lv_obj_draw_dsc_t *`. */

    /** Special events*/
    LV_EVENT_VALUE_CHANGED,       /**< The object's value has changed (i.e. slider moved)*/
    LV_EVENT_INSERT,              /**< A text is inserted to the object. The event data is `char *` being inserted.*/
    LV_EVENT_REFRESH,             /**< Notify the object to refresh something on it (for the user)*/
    LV_EVENT_READY,               /**< A process has finished*/
    LV_EVENT_CANCEL,              /**< A process has been cancelled */

    /** Other events*/
    LV_EVENT_DELETE,              /**< Object is being deleted*/
    LV_EVENT_CHILD_CHANGED,       /**< Child was removed, added, or its size, position were changed */
    LV_EVENT_CHILD_CREATED,       /**< Child was created, always bubbles up to all parents*/
    LV_EVENT_CHILD_DELETED,       /**< Child was deleted, always bubbles up to all parents*/
    LV_EVENT_SCREEN_UNLOAD_START, /**< A screen unload started, fired immediately when scr_load is called*/
    LV_EVENT_SCREEN_LOAD_START,   /**< A screen load started, fired when the screen change delay is expired*/
    LV_EVENT_SCREEN_LOADED,       /**< A screen was loaded*/
    LV_EVENT_SCREEN_UNLOADED,     /**< A screen was unloaded*/
    LV_EVENT_SIZE_CHANGED,        /**< Object coordinates/size have changed*/
    LV_EVENT_STYLE_CHANGED,       /**< Object's style has changed*/
    LV_EVENT_LAYOUT_CHANGED,      /**< The children position has changed due to a layout recalculation*/
    LV_EVENT_GET_SELF_SIZE,       /**< Get the internal size of a widget*/

    _LV_EVENT_LAST,               /** Number of default events*/


    LV_EVENT_PREPROCESS = 0x80,   /** This is a flag that can be set with an event so it's processed
                                      before the class default event processing */
} lv_event_code_t;

Enter the device event

 /**  Enter the device event  */
LV_EVENT_PRESSED,             /**<  Object is pressed  */
LV_EVENT_PRESSING,            /**<  Object is pressed  ( Continuously call... When pressed ) */
LV_EVENT_PRESS_LOST,          /**<  The object is still pressed , But the cursor / Slide your fingers away from the object  */
LV_EVENT_SHORT_CLICKED,       /**<  The object is pressed for a short period of time and then released , If you scroll, do not call  */
LV_EVENT_LONG_PRESSED,        /**<  The object is at least pressed long_press_time( Specify in the input device driver ), If you scroll, do not call  */
LV_EVENT_LONG_PRESSED_REPEAT, /**<  At every long_press_repeat_time ms mslong_press_time Then call , If you scroll, do not call  */
LV_EVENT_CLICKED,             /**<  If the object does not scroll , Then call  ( Press ) */
LV_EVENT_RELEASED,            /**<  The object is released and called  */
LV_EVENT_SCROLL_BEGIN,        /**<  Start rolling . The event parameter is NULL perhaps lv_anim_t *, You can modify */
LV_EVENT_SCROLL_END,          /**<  Roll over  */
LV_EVENT_SCROLL,              /**<  rolling  */
LV_EVENT_GESTURE,             /**<  Gesture detected . adopt  lv_indev_get_gesture_dir(lv_indev_get_act()); obtain  */
LV_EVENT_KEY,                 /**< KEY Sent to object .  adopt  lv_indev_get_key(lv_indev_get_act()); Get the secret key  */
LV_EVENT_FOCUSED,             /**<  The object is focused  */
LV_EVENT_DEFOCUSED,           /**<  Object unfocus  */
LV_EVENT_LEAVE,               /**<  The object is unfocused but still selected  */
LV_EVENT_HIT_TEST,            /**<  Perform advanced hit test  ( Read the manual carefully ) */

LV_EVENT_PRESSED： Object is pressed
LV_EVENT_PRESSING： Object is pressed ( Continuously call... When pressed )
LV_EVENT_PRESS_LOST： The object is still pressed , But the cursor / Slide your fingers away from the object
LV_EVENT_SHORT_CLICKED： The object is pressed for a short period of time and then released , If you scroll, do not call
LV_EVENT_LONG_PRESSED： The object is at least pressed long_press_time( Specify in the input device driver ), If you scroll, do not call
LV_EVENT_LONG_PRESSED_REPEAT： At every long_press_repeat_time ms mslong_press_time Then call , If you scroll, do not call
LV_EVENT_CLICKED： If the object does not scroll , Then call ( Press )
LV_EVENT_RELEASED： The object is released and called
LV_EVENT_SCROLL_BEGIN： Start rolling . The event parameter is NULL perhaps lv_anim_t *, You can modify
LV_EVENT_SCROLL_END： Roll over
LV_EVENT_SCROLL： rolling
LV_EVENT_GESTURE： Gesture detected .lv_indev_get_gesture_dir(lv_indev_get_act()); Get gestures
LV_EVENT_KEY：KEY Sent to object . adopt lv_indev_get_key(lv_indev_get_act()); Get the secret key
LV_EVENT_FOCUSED： The object is focused
LV_EVENT_DEFOCUSED： Object unfocus
LV_EVENT_LEAVE： The object is unfocused but still selected
LV_EVENT_HIT_TEST： Perform advanced hit test ( Read the manual carefully )

Graphic Events

/**  Graphic Events  */
LV_EVENT_COVER_CHECK,        /**<  Check whether the object completely covers an area .  The event parameter is  lv_cover_check_info_t * .*/
LV_EVENT_REFR_EXT_DRAW_SIZE, /**<  Get the additional drawing area needed around the object  (e.g.  shadow ). The event parameter used to store the size is  lv_coord_t * .*/
LV_EVENT_DRAW_MAIN_BEGIN,    /**<  Start the main drawing stage  */
LV_EVENT_DRAW_MAIN,          /**<  Execute main drawing  */
LV_EVENT_DRAW_MAIN_END,      /**<  Complete the main drawing stage  */
LV_EVENT_DRAW_POST_BEGIN,    /**<  Start the post drawing stage  ( When all sub objects are drawn )*/
LV_EVENT_DRAW_POST,          /**<  Execute post plot  ( When all sub objects are drawn )*/
LV_EVENT_DRAW_POST_END,      /**<  Finish the later drawing stage  ( When all sub objects are drawn )*/
LV_EVENT_DRAW_PART_BEGIN,    /**<  Start part of the drawing . The event parameter is  lv_obj_draw_dsc_t * . */
LV_EVENT_DRAW_PART_END,      /**<  Complete some drawings . The event parameter is  lv_obj_draw_dsc_t * . */

LV_EVENT_COVER_CHECK： Check whether the object completely covers an area . The event parameter is lv_cover_check_info_t * .
LV_EVENT_REFR_EXT_DRAW_SIZE： Get the additional drawing area needed around the object (e.g. shadow ). The event parameter used to store the size is lv_coord_t * .
LV_EVENT_DRAW_MAIN_BEGIN： Start the main drawing stage
LV_EVENT_DRAW_MAIN： Execute main drawing
LV_EVENT_DRAW_MAIN_END： Complete the main drawing stage
LV_EVENT_DRAW_POST_BEGIN： Start the post drawing stage ( When all sub objects are drawn )
LV_EVENT_DRAW_POST： Execute post plot ( When all sub objects are drawn )
LV_EVENT_DRAW_POST_END： Finish the later drawing stage ( When all sub objects are drawn )
LV_EVENT_DRAW_PART_BEGIN： Start part of the drawing . The event parameter is lv_obj_draw_dsc_t * .
LV_EVENT_DRAW_PART_END： Complete some drawings . The event parameter is lv_obj_draw_dsc_t * .

Other events

 /**  Other events  */
LV_EVENT_DELETE,              /**<  Object is being deleted  */
LV_EVENT_CHILD_CHANGED,       /**<  Child objects are being removed / add to , Location / The size is being changed  */
LV_EVENT_CHILD_CREATED,       /**<  Child objects are created , Bubble for all parent objects  */
LV_EVENT_CHILD_DELETED,       /**<  Sub objects are deleted , Bubble for all parent objects  */
LV_EVENT_SCREEN_UNLOAD_START, /**<  Screen uninstall starts , Calling  lv_scr_load/lv_scr_load_anim  Trigger immediately  */
LV_EVENT_SCREEN_LOAD_START,   /**<  Screen loading starts ,  Triggered when the screen change delay expires  */
LV_EVENT_SCREEN_LOADED,       /**<  Load screen , Called when all animations are complete  */
LV_EVENT_SCREEN_UNLOADED,     /**<  Uninstall screen , Called when all animations are complete  */
LV_EVENT_SIZE_CHANGED,        /**<  Coordinates of objects / The size is changed  */
LV_EVENT_STYLE_CHANGED,       /**<  The object style is changed  */
LV_EVENT_LAYOUT_CHANGED,      /**<  The position of the object calculated by the layout is changed  */
LV_EVENT_GET_SELF_SIZE,       /**<  Get the internal size of the part  */

LV_EVENT_DELETE： Object is being deleted
LV_EVENT_CHILD_CHANGED： Child objects are being removed / add to , Location / The size is being changed
LV_EVENT_CHILD_CREATED： Child objects are created , Bubble for all parent objects
LV_EVENT_CHILD_DELETED： Sub objects are deleted , Bubble for all parent objects
LV_EVENT_SCREEN_UNLOAD_START： Screen uninstall starts , Calling lv_scr_load/lv_scr_load_anim Trigger immediately
LV_EVENT_SCREEN_LOAD_START： Screen loading starts , Triggered when the screen change delay expires
LV_EVENT_SCREEN_LOADED： Load screen , Called when all animations are complete
LV_EVENT_SCREEN_UNLOADED： Uninstall screen , Called when all animations are complete
LV_EVENT_SIZE_CHANGED： Coordinates of objects / The size is changed
LV_EVENT_STYLE_CHANGED： The object style is changed
LV_EVENT_LAYOUT_CHANGED： The position of the object calculated by the layout is changed
LV_EVENT_GET_SELF_SIZE： Get the internal size of the part

Special events

/** Special events*/
LV_EVENT_VALUE_CHANGED,       /**<  The value of the object is changed  (i.e.  Slider movement ) */
LV_EVENT_INSERT,              /**<  Text is inserted into the object . The data inserted by the event is char * .*/
LV_EVENT_REFRESH,             /**<  The notification object refreshes the display on it  ( For the user ) */
LV_EVENT_READY,               /**<  A process has been completed  */
LV_EVENT_CANCEL,              /**<  A process was canceled  */

LV_EVENT_VALUE_CHANGED： The value of the object is changed (i.e. Slider movement )
LV_EVENT_INSERT： Text is inserted into the object . The data inserted by the event is char * .
LV_EVENT_REFRESH： The notification object refreshes the display on it ( For the user )
LV_EVENT_READY： A process has been completed
LV_EVENT_CANCEL： A process was canceled

LV_EVENT_REFRESH ： Let the user use it to notify the object to refresh

Custom events

Any custom event code can be registered through the following function

uint32_t <EVENT_CODE> = lv_event_register_id();
/* example: */
uint32_t USER_Event_ONE = lv_event_register_id();

Send events

Send events manually ( Include custom events )：

lv_event_send(obj, <EVENT_CODE> &some_data).

Callback Arguments

lv_event_t Is the only parameter passed to the event callback ！ Include all data .

typedef struct _lv_event_t {
    struct _lv_obj_t * target;
    struct _lv_obj_t * current_target;
    lv_event_code_t code;
    void * user_data;
    void * param;
    struct _lv_event_t * prev;
    uint8_t deleted : 1;
    uint8_t stop_processing : 1;
    uint8_t stop_bubbling : 1;
} lv_event_t;

of lv_event_t Function of

/*  Get event code  */
lv_event_get_code(e)
/*  Gets the object that sent the event  */
lv_event_get_current_target(e)
/*  Gets the object that originally triggered the event , Bubbling related  */
lv_event_get_target(e)
/*  Get the pointer passed as the last parameter  */
lv_event_get_user_data(e)
/*  Get the parameter passed as the last parameter  */
lv_event_get_param(e)