Crashing in lv_msg_subsribe_obj- ESP32 T-RGB - Squareline project

How-to
#1

I have a project that I created the UI in Squareline Studio adding logic from lilygo’s factory example to support the hardware. However, if I add a call to lv_msg_subscribe in my ui.c code, I get an immediate crash somewhere in that call.

With burn and crash debugging (I don’t have a debugger setup, just upload/moniotr through usb serial port), it’s been exceedingly slow tracing through the source to find out what’s crashing.

ui.h
====
#define MSG_BAT_VOLT_UPDATE       1
#define MSG_TOUCH_UPDATE          2
#define MSG_WIFI_UPDATE_OPTIONS   3
#define MSG_WIFI_UPDATE_TEXT      4
#define MSG_WIFI_MESSAGE          5

ui.ino
====

    Serial.println("no networks found");
    str = "no networks found";

    lv_msg_send(MSG_WIFI_UPDATE_TEXT, str.c_str());
    lv_msg_send(MSG_WIFI_UPDATE_OPTIONS, "");

ui.c
====

lv_obj_t * ui_ScreenWiFi_DropdownSSID;
void ui_event_ScreenWiFi_DropdownSSID(lv_event_t * e);

...

void ui_event_ScreenWiFi_DropdownSSID(lv_event_t * e)
{

    lv_event_code_t event_code = lv_event_get_code(e);
    lv_obj_t *dropdownSSID = (lv_obj_t *)lv_event_get_target(e);
    lv_msg_t *m = lv_event_get_msg(e);

    if (event_code == LV_EVENT_MSG_RECEIVED)
    {
        switch (lv_msg_get_id(m)) 
        {
            case MSG_WIFI_UPDATE_OPTIONS:
                lv_dropdown_set_options(dropdownSSID, lv_msg_get_payload(m));
                break;
            case MSG_WIFI_UPDATE_TEXT:
                lv_dropdown_set_text(dropdownSSID, lv_msg_get_payload(m));
                break;
            default:
                break;
        }
    }

}

...

void ui_init(void)
{
    lv_disp_t * dispp = lv_disp_get_default();
    lv_theme_t * theme = lv_theme_default_init(dispp, lv_palette_main(LV_PALETTE_BLUE), lv_palette_main(LV_PALETTE_RED),
                                               false, LV_FONT_DEFAULT);
    lv_disp_set_theme(dispp, theme);
    ui_ScreenMain_screen_init();
    ui_ScreenSetup_screen_init();
    ui_ScreenWiFi_screen_init();
    lv_disp_load_scr(ui_ScreenMain);

    lv_obj_add_event_cb(ui_ScreenWiFi_DropdownSSID, ui_event_ScreenWiFi_DropdownSSID, LV_EVENT_MSG_RECEIVED, NULL);
    if (ui_ScreenWiFi_DropdownSSID != NULL)
    {
	
		// uncommenting either or both of these results in a crash that occurs somewhere in the lv_msg_subsribe_obj code
		
        //lv_msg_subsribe_obj(MSG_WIFI_UPDATE_OPTIONS, ui_ScreenWiFi_DropdownSSID, NULL);
        //lv_msg_subsribe_obj(MSG_WIFI_UPDATE_TEXT, ui_ScreenWiFi_DropdownSSID, NULL);    
		
    }

}

Here’s what I have… Any pointers on trying to debug this?

#2

Fixed it, had to call lv_msg_init();

Documentation does not mention having to call lv_msg_init();

Calling this is vital and should be in the documentation. A flag in the code to bounce all the API calls if the init hasn’t been called would be extremely useful.