Lv_scr_load_anim does not work properly in LVGL 7.81 and 7.9


 Lv_scr_load_anim does not work properly in LVGL 7.81 and 7.9, But it works fine on LVGL7.8.0

What MCU/Processor/Board and compiler are you using?


What LVGL version are you using?

 V7.8.1 or V7.9.0

Code to reproduce

Add a code snippet which can run in the simulator. It should contain only the relevant code that compiles without errors when separated from your main code base.

The code block(s) should be formatted like:

void test_screen_1(void)
	lv_obj_t* one = lv_obj_create(NULL, NULL); 
	lv_obj_t* label = lv_label_create(one, NULL);       
	lv_obj_set_size(one, LV_HOR_RES, LV_VER_RES);       
	lv_obj_align(label, one, LV_ALIGN_CENTER, 0, 0);   
	lv_obj_set_style_local_bg_color(one, LV_OBJ_PART_MAIN, LV_STATE_DEFAULT,
	lv_label_set_text(label, "ONE");   
	lv_scr_load_anim(one, LV_SCR_LOAD_ANIM_FADE_ON, 100, 0, true);
void test_screen_2(void)
	lv_obj_t* two = lv_obj_create(NULL, NULL);  
	lv_obj_t*  label = lv_label_create(two, NULL);        
	lv_obj_set_size(two, LV_HOR_RES, LV_VER_RES);  
	lv_obj_align(label, two, LV_ALIGN_CENTER, 0, 0);  
	lv_obj_set_style_local_bg_color(two, LV_OBJ_PART_MAIN, LV_STATE_DEFAULT,
	lv_label_set_text(label, "TWO");  
	lv_scr_load_anim(two, LV_SCR_LOAD_ANIM_FADE_ON, 100, 0, true);

static void test_screen_task(struct _lv_task_t* task)
	static bool toggle_flag;
	if (toggle_flag)
	toggle_flag = !toggle_flag;

int main(int argc, char** argv)
	/*Initialize LittlevGL*/
	/*Initialize the HAL for LittlevGL*/

	lv_obj_t * scr = lv_obj_create(lv_scr_act(), NULL);
	lv_obj_set_size(scr, LV_HOR_RES, LV_VER_RES);
	lv_task_create(test_screen_task, 1000, LV_TASK_PRIO_LOW, NULL);

	while (1) {
		/* Periodically call the lv_task handler.
		* It could be done in a timer interrupt or an OS task too.*/
		Sleep(10);       /*Just to let the system breathe */

	return 0;

The following is the error log information

Error: lv_obj_get_disp (lv_obj.c #2126 lv_obj_get_disp())
Error: NULL pointer (0x00000000) (lv_debug.c #127 lv_debug_log_error())

Screenshot and/or video

If possible, add screenshots and/or videos about the current state.