Move with objects

How-to
1

Hi,
please, is it possible move with button when I click on it?

My example:
wifi_screen = lv_cont_create(body, NULL);
lv_cont_set_fit(wifi_screen, false, true);
lv_cont_set_layout(wifi_screen, LV_LAYOUT_COL_M);

lv_obj_t * wifi_button1 = lv_btn_create(wifi_screen, NULL);
lv_btn_set_layout(wifi_button1 , LV_LAYOUT_ROW_M);
lv_obj_set_width(wifi_button1 , APP_SCREEN_WIDTH-40);
lv_obj_set_free_ptr(wifi_button1 , (void*)wifi);
lv_btn_set_action(wifi_button1 , LV_BTN_ACTION_CLICK, _app_screen_ctrl_wifi_btn_click);

lv_obj_t * wifi_button1 = lv_btn_create(wifi_screen, NULL);
lv_btn_set_layout(wifi_button1 , LV_LAYOUT_ROW_M);
lv_obj_set_width(wifi_button1 , APP_SCREEN_WIDTH-40);
lv_obj_set_free_ptr(wifi_button1 , (void*)wifi);
lv_btn_set_action(wifi_button1 , LV_BTN_ACTION_CLICK, _app_screen_ctrl_wifi_btn_click);

Now, I have lot of buttons and I want move clicked button to top. Is it possible?

I tried this:
lv_obj_set_pos(obj, 0, 0);
lv_obj_invalidate(obj);
lv_obj_invalidate(lv_obj_get_parent(obj));

Not working.

Please, could you help me?

DSC_0201
DSC_0201.JPG4608×2592 1.14 MB

2

I don’t quite understand. Are you trying to move the button to the foreground (i.e. Z-axis) or to the top of the screen (i.e. Y-axis)?

3

I want move to top of the screen (y-axis). I thought order of the buttons. When clicked one of these buttons, it should be first.

4

If you have a reference to the button, one of these two APIs should work (not sure which one): lv_obj_move_foreground or lv_obj_move_background. They adjust whether the button is at the beginning or end of the list of children.

5

Thank you, but I am still using v5.3, is it possible move it in this version? I still have some issues when migrating to v6.0.

These functions are not in the version 5.3

6

I’m not sure about 5.3. That version is getting old at this point.

7

OK, I understand. I solved with new function.

bool lv_obj_move(lv_obj_t * obj, lv_obj_t * obj_after)
{
	lv_obj_t * parent = lv_obj_get_parent(obj);
	lv_obj_t * parent_after = NULL;

	/* Object must exists and must have parent */
	if(obj == NULL || parent == NULL)
		return false;

	if(obj_after)
		parent_after = lv_obj_get_parent(obj_after);

	/* Both object must have same parent */
	if(obj_after != NULL && parent != parent_after)
		return false;

	/* Move object in parent list */
	lv_ll_move_before(&parent->child_ll, obj, obj_after);

	/* Move object in the group list */
	lv_group_t * group = obj->group_p;
	if(group)
	{
		lv_obj_t ** obj_pp = NULL;
		LL_READ(group->obj_ll, obj_pp)
		{
			if(*obj_pp == obj)
				break;
		}

		lv_obj_t ** obj_next_pp = NULL;
		lv_obj_t * next = lv_ll_get_prev(&parent->child_ll, obj);
		if(next)
		{
			LL_READ(group->obj_ll, obj_next_pp)
			{
				if(*obj_next_pp == next)
					break;
			}
		}

		if(obj_pp)
			lv_ll_move_before(&group->obj_ll, obj_pp, obj_next_pp);
	}

	lv_obj_invalidate(obj);

	/*Send a signal to the parent to notify it about the child delete*/
	if(parent != NULL)
		parent->signal_func(parent, LV_SIGNAL_CHILD_CHG, NULL);

	return true;
}
8

Send a PR to dev-6.1 if you wish; I think that function could be useful in upstream LittlevGL as it gives more flexibility than just moving to the front or back.

9

I agree with @embeddedt, it would be useful feature in v6.1 too. So please send a PR. (Let us know if you need help with that.)