54     lv_obj_t * indicator = lv_obj_create(footer);  in lv_example_observer_4()  local
55     lv_obj_remove_style(indicator, NULL, 0);  in lv_example_observer_4()
56     lv_obj_set_style_bg_opa(indicator, LV_OPA_40, 0);  in lv_example_observer_4()
57     lv_subject_add_observer_obj(&current_tab_subject, indicator_observer_cb, indicator, NULL);  in lv_example_observer_4()
58     lv_obj_set_height(indicator, 10);  in lv_example_observer_4()
59     lv_obj_align(indicator, LV_ALIGN_BOTTOM_LEFT, 0, 0);  in lv_example_observer_4()
60     lv_obj_add_flag(indicator, LV_OBJ_FLAG_IGNORE_LAYOUT);  in lv_example_observer_4()
63     lv_obj_update_layout(indicator);  in lv_example_observer_4()
188     lv_obj_t * indicator = lv_observer_get_target(observer);  in indicator_observer_cb()  local
190     lv_obj_t * footer = lv_obj_get_parent(indicator);  in indicator_observer_cb()
192     lv_obj_set_width(indicator, lv_obj_get_width(btn_act));  in indicator_observer_cb()
199     lv_anim_set_var(&a, indicator);  in indicator_observer_cb()
200     lv_anim_set_values(&a, lv_obj_get_x(indicator), lv_obj_get_x(btn_act));  in indicator_observer_cb()