How to fix irregular Application crash in _lv_event_mark_deleted?

How-to
1

Hi,

I am working on an application, in which there is a parent screen on top of that I am creating other popup screens (by taking the parent as “lv_scr_act()” ) on an event. Then I am trying to delete the pop-up screen by a button click event on the pop-up, my application is crashing irregularly at _lv_event_mark_deleted. Can you please help me to figure out what might be the reason for the crashes?

Base screen:

lv_obj_t *g_main_screen;

lv_obj_t* get_main_screen_without_borders(void)
{
g_main_screen = lv_obj_create(lv_scr_act());
lv_obj_center(g_main_screen);
lv_obj_set_size(g_main_screen, DISP_MAX_HORIZONTAL_RESOLUTION, DISP_MAX_VERTICAL_RESOLUTION);
lv_obj_set_style_bg_color(g_main_screen, lv_color_black(), LV_PART_MAIN);
lv_obj_set_style_border_color(g_main_screen, lv_color_hex(0x000000), LV_PART_MAIN);
lv_obj_clear_flag(g_main_screen, LV_OBJ_FLAG_SCROLLABLE);

return g_main_screen;
}

Primary Screen (or Application screen):

    lv_obj_t *app_scrn = get_main_screen_without_borders();
	lv_obj_clear_flag(app_scrn , LV_OBJ_FLAG_GESTURE_BUBBLE);
	lv_obj_add_event_cb(app_scrn , app_scrn_swipe_gesture_cb, LV_EVENT_GESTURE, NULL);

Secondary Screen (Pop-up screen):

 static lv_obj_t  *pop_up_obj ;

 static void message_screen(const char *data);

static void dismiss_event_cb(lv_event_t * e)
{
char *my_data  = (char *)e->user_data;
if(code == LV_EVENT_CLICKED)
{
		lv_obj_del(pop_up_obj);
		message_screen(my_data);
		
 }
}

void pop_up_screen (void)
{
   static char u_data[9];

    pop_up_obj = lv_obj_create(lv_scr_act());
	lv_obj_set_size(pop_up_obj , DISP_MAX_HORIZONTAL_RESOLUTION, DISP_MAX_VERTICAL_RESOLUTION);
	lv_obj_align(pop_up_obj , LV_ALIGN_CENTER, 0, 0);
	lv_obj_set_style_bg_color(pop_up_obj , lv_color_black(), LV_PART_MAIN);
	lv_obj_set_style_bg_opa(pop_up_obj , LV_OPA_100, LV_PART_MAIN);
	lv_obj_set_style_radius(pop_up_obj , LV_RADIUS_CIRCLE, 0);
	lv_obj_clear_flag(pop_up_obj , LV_OBJ_FLAG_SCROLLABLE);
	lv_obj_set_style_border_width(pop_up_obj , 0, LV_PART_MAIN);

    lv_obj_t *dismiss_button = lv_label_create(pop_up_obj);
	lv_label_set_text(dismiss_button, "Dismiss");
	lv_obj_align(dismiss_button, LV_ALIGN_TOP_MID, -60, 284);
	lv_obj_set_style_text_color(dismiss_button,lv_color_hex(0x9f9f9f),LV_PART_MAIN);
	lv_obj_set_style_text_font(dismiss_button, &barlow_mediumItalic_44, LV_PART_MAIN);
	lv_obj_add_flag(dismiss_button, LV_OBJ_FLAG_CLICKABLE);
	lv_obj_add_event_cb(dismiss_button, dismiss_event_cb, LV_EVENT_CLICKED, &u_data);
	lv_obj_set_ext_click_area(dismiss_button, 20);
  }
 
static void auto_delete_scrn_timer_cb(lv_timer_t *timer)
{
lv_obj_del(pop_up_obj);
}

static void message_screen(const char *data)
{
pop_up_obj = lv_obj_create(lv_scr_act());
lv_obj_set_size(pop_up_obj , DISP_MAX_HORIZONTAL_RESOLUTION, DISP_MAX_VERTICAL_RESOLUTION);
lv_obj_align(pop_up_obj , LV_ALIGN_CENTER, 0, 0);
lv_obj_set_style_bg_color(pop_up_obj , lv_color_black(), LV_PART_MAIN);
lv_obj_set_style_bg_opa(pop_up_obj , LV_OPA_100, LV_PART_MAIN);
lv_obj_set_style_radius(pop_up_obj , LV_RADIUS_CIRCLE, 0);
lv_obj_clear_flag(pop_up_obj , LV_OBJ_FLAG_SCROLLABLE);
lv_obj_set_style_border_width(pop_up_obj , 0, LV_PART_MAIN);

	lv_obj_t * message_label= lv_label_create(pop_up_obj);
	lv_label_set_text_fmt(message_label,"%s", data);
	lv_obj_align(message_label, LV_ALIGN_TOP_MID, 5, 151);
	lv_obj_set_style_text_font(message_label, &barlow_bold_58, LV_PART_MAIN);
	lv_obj_set_style_text_color(message_label,lv_color_hex(0xffffff),LV_PART_MAIN);

    lv_timer_t *auto_delete_scrn_timer = lv_timer_create(auto_delete_scrn_timer_cb, 900, NULL);
    lv_timer_set_repeat_count(auto_delete_scrn_timer , 1);
}

Please, look into my above code implementation, and help on the same.

Kind Regards,

Amaresh

2

Hi,

After fixind a few obvious missing defines and fonts I found that code in dismiss_event_cb is not defined. Of course it can be also easily fixed but it might be the root of the problem as well, as I can’t see where it is initialized.

After changing it to if(lv_event_get_code(e) == LV_EVENT_CLICKED) it works well for me.

If it doesn’t help, please do these:

  • Enable LV_MEM_ADD_JUNK in lv_mem.c
  • Enable all LV_USE_ASSERT_* in lv_conf.h
  • Enable the logging of LVGL
1 Like
3

Hi,

Thanks, @kisvegabor for your suggestion. Yeah right, by mistake I missed this lv_event_code_t code = lv_event_get_code(event); to write here.

By applying your suggestion :

  • Enable LV_MEM_ADD_JUNK in lv_mem.c
  • Enable all LV_USE_ASSERT_* in lv_conf.h

I got that it is crashing during pop_up_screen deletion, my system didn’t fetch the address of the pop_up_obj. It might be due to the thread has not been handled properly during the click event of dismiss_button.

So, I made a little flow change and now I am not deleting the pop_up_screen on the click event, I am just modifying the same screen for the message on the click event. And deleting the screen through timer callback after showing the message.

Thanks again, Now this is working fine for me. :slight_smile:

Regards,

Amaresh Ray

1 Like
4

Great! Happy to hear that it works now.