Added an event callback to know what setting category is opened and closed, reworked the way the side screen is cleaned (refactoring), added a background color on the selected item of the list

src/W800_SDK_v1.00.10/app/gfx/settings_screen.c

@@ -20,7 +20,7 @@ static const char* vibration_force = "1\n2\n3\n4\n5\n6\n7\n8";
 
 static const char* language_options = "Francais\nDeutsch\nEnglish";
 
-static lv_obj_t *add_menu_list_item(lv_obj_t *list, const char *text, lv_event_cb_t event_cb, void *user_data);
+static lv_obj_t *add_menu_list_item(lv_obj_t *list, const char *text, lv_event_cb_t event_cb, void *user_data, SettingsScreenCategory_e category);
 static void update_menu_list_item_text(lv_obj_t *menu_list_item, const char *text);
 
 static void _simulate_side_screen_item_click(SettingsScreen_t * const settingsScreen, lv_obj_t *item);
@@ -262,6 +262,8 @@ static void about_refresh_timer_cb(lv_timer_t *timer)
 {
     SettingsScreen_t *settingsScreen = timer->user_data;
 
+    if(!settingsScreen->about_refresh_timer) return;
+   
     static uint8_t timer_divider = 6;
     if(timer_divider++ == 6)
     { 
@@ -275,9 +277,6 @@ static void about_refresh_timer_cb(lv_timer_t *timer)
 
 static void load_time_and_date_side_screen(SettingsScreen_t *settingsScreen)
 {
-    lv_obj_clean(settingsScreen->side_screen);
-    _reset_switch_pointers(settingsScreen);
-
     uint8_t hour = 0, minute = 0, second = 0, day = 0, month = 0, year = 0;
     if(settingsScreen->settingsScreenAPIInterface.setTimeSettingsCb)
         settingsScreen->settingsScreenAPIInterface.setTimeSettingsCb(&hour, &minute, &second, &day, &month, &year, SETTING_MODE_GET);
@@ -393,9 +392,6 @@ static void load_time_and_date_side_screen(SettingsScreen_t *settingsScreen)
 
 static void load_display_side_screen(SettingsScreen_t *settingsScreen)
 {
-    lv_obj_clean(settingsScreen->side_screen);
-    _reset_switch_pointers(settingsScreen);
-
     lv_obj_t *label = lv_label_create(settingsScreen->side_screen);
     lv_label_set_text_static(label, "Brightness :");
 
@@ -483,9 +479,6 @@ static void load_display_side_screen(SettingsScreen_t *settingsScreen)
 
 static void load_notifications_side_screen(SettingsScreen_t *settingsScreen)
 {
-    lv_obj_clean(settingsScreen->side_screen);
-    _reset_switch_pointers(settingsScreen);
-
     lv_obj_t *label = lv_label_create(settingsScreen->side_screen);
     lv_label_set_text_static(label, "Vibrate on\nnotifications :");
 
@@ -512,9 +505,6 @@ static void load_notifications_side_screen(SettingsScreen_t *settingsScreen)
 
 static void load_connectivity_side_screen(SettingsScreen_t *settingsScreen)
 {
-    lv_obj_clean(settingsScreen->side_screen);
-    _reset_switch_pointers(settingsScreen);
-
     lv_obj_t *label = lv_label_create(settingsScreen->side_screen);
     lv_label_set_text_static(label, "Connectivity :");
 
@@ -588,9 +578,6 @@ static void load_connectivity_side_screen(SettingsScreen_t *settingsScreen)
 
 static void load_language_side_screen(SettingsScreen_t *settingsScreen)
 {
-    lv_obj_clean(settingsScreen->side_screen);
-    _reset_switch_pointers(settingsScreen);
-
     lv_obj_t *label = lv_label_create(settingsScreen->side_screen);
     lv_label_set_text_static(label, "Language :");
 
@@ -605,9 +592,6 @@ static void load_language_side_screen(SettingsScreen_t *settingsScreen)
 
 static void load_about_side_screen(SettingsScreen_t *settingsScreen)
 {
-    lv_obj_clean(settingsScreen->side_screen);
-    _reset_switch_pointers(settingsScreen);
-
     lv_obj_t *label = lv_label_create(settingsScreen->side_screen);
     lv_label_set_text_static(label, "System Info :");
 
@@ -723,6 +707,17 @@ void settings_screen_init(SettingsScreen_t * const settingsScreen)
     memset(settingsScreen, 0, sizeof(SettingsScreen_t));
 }
 
+void settings_screen_register_on_state_change_cb(SettingsScreen_t * const settingsScreen, SettingsScreenOnStateChangeCb_t settingsScreenOnStateChangeCb)
+{
+    if(!settingsScreen)
+    {
+        LV_LOG_ERROR("NULL pointer given !");
+        return;
+    }
+
+    settingsScreen->settingsScreenOnStateChangeCb = settingsScreenOnStateChangeCb;
+}
+
 void settings_screen_register_API_interface(SettingsScreen_t * const settingsScreen, SettingsScreenAPIInterface_t * const settingsScreenAPIInterface)
 {
     if(!settingsScreen)
@@ -778,12 +773,12 @@ void settings_screen_create(SettingsScreen_t * const settingsScreen)
     lv_obj_set_scroll_dir(settingsScreen->side_screen, LV_DIR_VER);
 
     // We add all the menu list items
-    settingsScreen->time_and_date_item = add_menu_list_item(menu_list, translation_get_word(TRANSLATION_TIME_AND_DATE), &(menu_list_item_event_handler), settingsScreen);
+    settingsScreen->time_and_date_item = add_menu_list_item(menu_list, translation_get_word(TRANSLATION_TIME_AND_DATE), &(menu_list_item_event_handler), settingsScreen, SETTINGS_SCREEN_CATEGORY_TIME_AND_DATE);
-    settingsScreen->display_item = add_menu_list_item(menu_list, translation_get_word(TRANSLATION_DISPLAY), &(menu_list_item_event_handler), settingsScreen);
+    settingsScreen->display_item = add_menu_list_item(menu_list, translation_get_word(TRANSLATION_DISPLAY), &(menu_list_item_event_handler), settingsScreen, SETTINGS_SCREEN_CATEGORY_DISPLAY);
-    settingsScreen->notifications_item = add_menu_list_item(menu_list, translation_get_word(TRANSLATION_NOTIFICATIONS), &(menu_list_item_event_handler), settingsScreen);
+    settingsScreen->notifications_item = add_menu_list_item(menu_list, translation_get_word(TRANSLATION_NOTIFICATIONS), &(menu_list_item_event_handler), settingsScreen, SETTINGS_SCREEN_CATEGORY_NOTIFICATION);
-    settingsScreen->connectivity_item = add_menu_list_item(menu_list, translation_get_word(TRANSLATION_CONNECTIVITY), &(menu_list_item_event_handler), settingsScreen);
+    settingsScreen->connectivity_item = add_menu_list_item(menu_list, translation_get_word(TRANSLATION_CONNECTIVITY), &(menu_list_item_event_handler), settingsScreen, SETTINGS_SCREEN_CATEGORY_CONNECTIVITY);
-    settingsScreen->language_item = add_menu_list_item(menu_list, translation_get_word(TRANSLATION_LANGUAGE), &(menu_list_item_event_handler), settingsScreen);
+    settingsScreen->language_item = add_menu_list_item(menu_list, translation_get_word(TRANSLATION_LANGUAGE), &(menu_list_item_event_handler), settingsScreen, SETTINGS_SCREEN_CATEGORY_LANGUAGE);
-    settingsScreen->about_item = add_menu_list_item(menu_list, translation_get_word(TRANSLATION_ABOUT), &(menu_list_item_event_handler), settingsScreen);
+    settingsScreen->about_item = add_menu_list_item(menu_list, translation_get_word(TRANSLATION_ABOUT), &(menu_list_item_event_handler), settingsScreen, SETTINGS_SCREEN_CATEGORY_ABOUT);
 
     // We register the event callback to handle gesture
     lv_obj_add_event_cb(settingsScreen->display, &(gesture_event_cb), LV_EVENT_GESTURE, settingsScreen);
@@ -802,6 +797,12 @@ void settings_screen_destroy(SettingsScreen_t * const settingsScreen)
         return;
     }
 
+    if (settingsScreen->last_selected_item)
+    {
+        if (settingsScreen->settingsScreenOnStateChangeCb)
+            settingsScreen->settingsScreenOnStateChangeCb(SETTINGS_SCREEN_STATE_CLOSED, (SettingsScreenCategory_e)lv_obj_get_user_data(settingsScreen->last_selected_item));
+    }
+
     settingsScreen->hour_roller         = NULL;
     settingsScreen->minute_roller       = NULL;
     settingsScreen->second_roller       = NULL;
@@ -828,8 +829,21 @@ static void _simulate_side_screen_item_click(SettingsScreen_t * const settingsSc
     if(settingsScreen->last_selected_item)
         lv_obj_set_style_bg_color(settingsScreen->last_selected_item, lv_color_white(), LV_PART_MAIN);
 
+    // Let's call the settings screen on state change callback if registered
+    if(settingsScreen->settingsScreenOnStateChangeCb)
+        settingsScreen->settingsScreenOnStateChangeCb(SETTINGS_SCREEN_STATE_OPENED, (SettingsScreenCategory_e)lv_obj_get_user_data(item));
+
+    if(settingsScreen->last_selected_item)
+    {
+        if(settingsScreen->settingsScreenOnStateChangeCb)
+            settingsScreen->settingsScreenOnStateChangeCb(SETTINGS_SCREEN_STATE_CLOSED, (SettingsScreenCategory_e)lv_obj_get_user_data(settingsScreen->last_selected_item));
+    }
+
     settingsScreen->last_selected_item = item;
 
+    lv_obj_clean(settingsScreen->side_screen);
+    _reset_switch_pointers(settingsScreen);
+
     if(item == settingsScreen->time_and_date_item)
     {
         load_time_and_date_side_screen(settingsScreen);
@@ -861,7 +875,10 @@ static void _set_rtc_time_to_label(SettingsScreen_t * const settingsScreen)
     uint8_t hour = 0, minute = 0, second = 0, day = 0, month = 0, year = 0;
     if(settingsScreen->settingsScreenAPIInterface.setTimeSettingsCb)
         settingsScreen->settingsScreenAPIInterface.setTimeSettingsCb(&hour, &minute, &second, &day, &month, &year, SETTING_MODE_GET);
-    sprintf(settingsScreen->currentTime.current_time_text, "%u:%u:%u %s%u/%s%u/%u", hour, minute, second, 
+    sprintf(settingsScreen->currentTime.current_time_text, "%s%u:%s%u:%s%u %s%u/%s%u/%u", 
+    hour < 10 ? "0":"", hour,
+    minute < 10 ? "0":"", minute,
+    second < 10 ? "0":"", second,
     day < 10 ? "0":"", day,
     month + 1 < 10 ? "0":"", month + 1,
     year+1900);
@@ -951,7 +968,7 @@ static void _enable_time_and_date_rollers(bool enabled, SettingsScreen_t * const
     }
 }
 
-static lv_obj_t *add_menu_list_item(lv_obj_t *list, const char *text, lv_event_cb_t event_cb, void *user_data)
+static lv_obj_t *add_menu_list_item(lv_obj_t *list, const char *text, lv_event_cb_t event_cb, void *user_data, SettingsScreenCategory_e category)
 {
     lv_obj_t *btn = lv_list_add_btn(list, NULL, text);
     lv_obj_t *label = lv_obj_get_child(btn, 0);
@@ -962,6 +979,7 @@ static lv_obj_t *add_menu_list_item(lv_obj_t *list, const char *text, lv_event_c
         lv_label_set_long_mode(label, LV_LABEL_LONG_WRAP);
     }
 
+    lv_obj_set_user_data(btn, (void *)category);
     lv_obj_add_event_cb(btn, event_cb, LV_EVENT_CLICKED, user_data);
     return btn;
 }

src/W800_SDK_v1.00.10/app/gfx/settings_screen.h

@@ -33,6 +33,24 @@ typedef struct SettingsScreenAPIInterface
     void (*factoryResetCb)(void);
 } SettingsScreenAPIInterface_t;
 
+typedef enum SettingsScreenState
+{
+    SETTINGS_SCREEN_STATE_OPENED = 0,
+    SETTINGS_SCREEN_STATE_CLOSED
+} SettingsScreenState_e;
+
+typedef enum SettingsScreenCategory
+{
+    SETTINGS_SCREEN_CATEGORY_TIME_AND_DATE = 0,
+    SETTINGS_SCREEN_CATEGORY_DISPLAY,
+    SETTINGS_SCREEN_CATEGORY_NOTIFICATION,
+    SETTINGS_SCREEN_CATEGORY_CONNECTIVITY,
+    SETTINGS_SCREEN_CATEGORY_LANGUAGE,
+    SETTINGS_SCREEN_CATEGORY_ABOUT,
+} SettingsScreenCategory_e;
+
+typedef void (*SettingsScreenOnStateChangeCb_t)(SettingsScreenState_e settingsScreenState, SettingsScreenCategory_e settingsScreenCategory);
+
 typedef struct SettingsScreen
 {
     SettingsScreenAPIInterface_t settingsScreenAPIInterface;
@@ -108,10 +126,21 @@ typedef struct SettingsScreen
 
     /* Other */
     lv_timer_t *about_refresh_timer;
+    SettingsScreenOnStateChangeCb_t settingsScreenOnStateChangeCb;
 } SettingsScreen_t;
 
 void settings_screen_init(SettingsScreen_t * const settingsScreen);
 
+/**
+ * @brief Registers a callback function which will be called every time the state of the application changes ie : is opened or closed.
+ *        This callback should be used to initialize and deinitialize needed devices drivers like the magnetometer or the temperature sensor.
+ * @note The state of the application is passed as a parameter or the callback function. 
+ * 
+ * @param settingsScreen a pointer to the settings screen object structure.
+ * @param SettingsScreenOnStateChangeCb the callback of type @ref SettingsScreenOnStateChangeCb_t to register.
+ */
+void settings_screen_register_on_state_change_cb(SettingsScreen_t * const settingsScreen, SettingsScreenOnStateChangeCb_t SettingsScreenOnStateChangeCb);
+
 void settings_screen_register_API_interface(SettingsScreen_t * const settingsScreen, SettingsScreenAPIInterface_t * const settingsScreenAPIInterface);
 
 void settings_screen_create(SettingsScreen_t * const settingsScreen);

src/lvgl_win_sim/lv_port_win_codeblocks/settings_screen.c

@@ -26,7 +26,7 @@ static void _reset_switch_pointers(SettingsScreen_t * const settingsScreen)
     settingsScreen->ble_switch = NULL;
     settingsScreen->auto_set_time_switch = NULL;
 }
-static lv_obj_t *add_menu_list_item(lv_obj_t *list, const char *text, lv_event_cb_t event_cb, void *user_data);
+static lv_obj_t *add_menu_list_item(lv_obj_t *list, const char *text, lv_event_cb_t event_cb, void *user_data, SettingsScreenCategory_e category);
 static void update_menu_list_item_text(lv_obj_t *menu_list_item, const char *text);
 
 static void gesture_event_cb(lv_event_t *e)
@@ -164,9 +164,6 @@ static void about_refresh_timer_cb(lv_timer_t *timer)
 
 static void load_time_and_date_side_screen(SettingsScreen_t *settingsScreen)
 {
-    lv_obj_clean(settingsScreen->side_screen);
-    _reset_switch_pointers(settingsScreen);
-
     lv_obj_t *label = lv_label_create(settingsScreen->side_screen);
     lv_label_set_text_static(label, "Set Time & Date :");
 
@@ -254,9 +251,6 @@ static void load_time_and_date_side_screen(SettingsScreen_t *settingsScreen)
 
 static void load_display_side_screen(SettingsScreen_t *settingsScreen)
 {
-    lv_obj_clean(settingsScreen->side_screen);
-    _reset_switch_pointers(settingsScreen);
-
     lv_obj_t *label = lv_label_create(settingsScreen->side_screen);
     lv_label_set_text_static(label, "Brightness :");
 
@@ -323,9 +317,6 @@ static void load_display_side_screen(SettingsScreen_t *settingsScreen)
 
 static void load_notifications_side_screen(SettingsScreen_t *settingsScreen)
 {
-    lv_obj_clean(settingsScreen->side_screen);
-    _reset_switch_pointers(settingsScreen);
-
     lv_obj_t *label = lv_label_create(settingsScreen->side_screen);
     lv_label_set_text_static(label, "Vibrate on\nnotifications :");
 
@@ -352,9 +343,6 @@ static void load_notifications_side_screen(SettingsScreen_t *settingsScreen)
 
 static void load_connectivity_side_screen(SettingsScreen_t *settingsScreen)
 {
-    lv_obj_clean(settingsScreen->side_screen);
-    _reset_switch_pointers(settingsScreen);
-
     lv_obj_t *label = lv_label_create(settingsScreen->side_screen);
     lv_label_set_text_static(label, "Connectivity :");
 
@@ -407,9 +395,6 @@ static void load_connectivity_side_screen(SettingsScreen_t *settingsScreen)
 
 static void load_language_side_screen(SettingsScreen_t *settingsScreen)
 {
-    lv_obj_clean(settingsScreen->side_screen);
-    _reset_switch_pointers(settingsScreen);
-
     lv_obj_t *label = lv_label_create(settingsScreen->side_screen);
     lv_label_set_text_static(label, "Language :");
 
@@ -421,9 +406,6 @@ static void load_language_side_screen(SettingsScreen_t *settingsScreen)
 
 static void load_about_side_screen(SettingsScreen_t *settingsScreen)
 {
-    lv_obj_clean(settingsScreen->side_screen);
-    _reset_switch_pointers(settingsScreen);
-
     lv_obj_t *label = lv_label_create(settingsScreen->side_screen);
     lv_label_set_text_static(label, "System Info :");
 
@@ -521,7 +503,7 @@ static void load_about_side_screen(SettingsScreen_t *settingsScreen)
         lv_timer_del(settingsScreen->about_refresh_timer);
         settingsScreen->about_refresh_timer = NULL;
     }
-    settingsScreen->about_refresh_timer = lv_timer_create(&(about_refresh_timer_cb), 1000, settingsScreen);
+    settingsScreen->about_refresh_timer = lv_timer_create(&(about_refresh_timer_cb), 150, settingsScreen);
 }
 
 static void menu_list_item_event_handler(lv_event_t * e)
@@ -541,6 +523,17 @@ void settings_screen_init(SettingsScreen_t * const settingsScreen)
     memset(settingsScreen, 0, sizeof(SettingsScreen_t));
 }
 
+void settings_screen_register_on_state_change_cb(SettingsScreen_t * const settingsScreen, SettingsScreenOnStateChangeCb_t settingsScreenOnStateChangeCb)
+{
+    if(!settingsScreen)
+    {
+        LV_LOG_ERROR("NULL pointer given !");
+        return;
+    }
+
+    settingsScreen->settingsScreenOnStateChangeCb = settingsScreenOnStateChangeCb;
+}
+
 void settings_screen_register_API_interface(SettingsScreen_t * const settingsScreen, SettingsScreenAPIInterface_t * const settingsScreenAPIInterface)
 {
     if(!settingsScreen)
@@ -596,12 +589,12 @@ void settings_screen_create(SettingsScreen_t * const settingsScreen)
     lv_obj_set_scroll_dir(settingsScreen->side_screen, LV_DIR_VER);
 
     // We add all the menu list items
-    settingsScreen->time_and_date_item = add_menu_list_item(menu_list, "Time & Date", &(menu_list_item_event_handler), settingsScreen);
+    settingsScreen->time_and_date_item = add_menu_list_item(menu_list, "Time & Date", &(menu_list_item_event_handler), settingsScreen, SETTINGS_SCREEN_CATEGORY_TIME_AND_DATE);
-    settingsScreen->display_item = add_menu_list_item(menu_list, "Display", &(menu_list_item_event_handler), settingsScreen);
+    settingsScreen->display_item = add_menu_list_item(menu_list, "Display", &(menu_list_item_event_handler), settingsScreen, SETTINGS_SCREEN_CATEGORY_DISPLAY);
-    settingsScreen->notifications_item = add_menu_list_item(menu_list, "Notifications", &(menu_list_item_event_handler), settingsScreen);
+    settingsScreen->notifications_item = add_menu_list_item(menu_list, "Notifications", &(menu_list_item_event_handler), settingsScreen, SETTINGS_SCREEN_CATEGORY_NOTIFICATION);
-    settingsScreen->connectivity_item = add_menu_list_item(menu_list, "Connectivity", &(menu_list_item_event_handler), settingsScreen);
+    settingsScreen->connectivity_item = add_menu_list_item(menu_list, "Connectivity", &(menu_list_item_event_handler), settingsScreen, SETTINGS_SCREEN_CATEGORY_CONNECTIVITY);
-    settingsScreen->language_item = add_menu_list_item(menu_list, "Language", &(menu_list_item_event_handler), settingsScreen);
+    settingsScreen->language_item = add_menu_list_item(menu_list, "Language", &(menu_list_item_event_handler), settingsScreen, SETTINGS_SCREEN_CATEGORY_LANGUAGE);
-    settingsScreen->about_item = add_menu_list_item(menu_list, "About", &(menu_list_item_event_handler), settingsScreen);
+    settingsScreen->about_item = add_menu_list_item(menu_list, "About", &(menu_list_item_event_handler), settingsScreen, SETTINGS_SCREEN_CATEGORY_ABOUT);
 
     // We register the event callback to handle gesture
     lv_obj_add_event_cb(settingsScreen->display, &(gesture_event_cb), LV_EVENT_GESTURE, settingsScreen);
@@ -620,6 +613,12 @@ void settings_screen_destroy(SettingsScreen_t * const settingsScreen)
         return;
     }
 
+    if (settingsScreen->last_selected_item)
+    {
+        if (settingsScreen->settingsScreenOnStateChangeCb)
+            settingsScreen->settingsScreenOnStateChangeCb(SETTINGS_SCREEN_STATE_CLOSED, (SettingsScreenCategory_e)lv_obj_get_user_data(settingsScreen->last_selected_item));
+    }
+
     settingsScreen->hour_roller         = NULL;
     settingsScreen->minute_roller       = NULL;
     settingsScreen->second_roller       = NULL;
@@ -646,8 +645,21 @@ static void _simulate_side_screen_item_click(SettingsScreen_t * const settingsSc
     if(settingsScreen->last_selected_item)
         lv_obj_set_style_bg_color(settingsScreen->last_selected_item, lv_color_white(), LV_PART_MAIN);
 
+    // Let's call the settings screen on state change callback if registered
+    if(settingsScreen->settingsScreenOnStateChangeCb)
+        settingsScreen->settingsScreenOnStateChangeCb(SETTINGS_SCREEN_STATE_OPENED, (SettingsScreenCategory_e)lv_obj_get_user_data(item));
+
+    if(settingsScreen->last_selected_item)
+    {
+        if(settingsScreen->settingsScreenOnStateChangeCb)
+            settingsScreen->settingsScreenOnStateChangeCb(SETTINGS_SCREEN_STATE_CLOSED, (SettingsScreenCategory_e)lv_obj_get_user_data(settingsScreen->last_selected_item));
+    }
+
     settingsScreen->last_selected_item = item;
 
+    lv_obj_clean(settingsScreen->side_screen);
+    _reset_switch_pointers(settingsScreen);
+
     if(item == settingsScreen->time_and_date_item)
     {
         load_time_and_date_side_screen(settingsScreen);
@@ -710,7 +722,7 @@ static void _enable_time_and_date_rollers(bool enabled, SettingsScreen_t * const
     }
 }
 
-static lv_obj_t *add_menu_list_item(lv_obj_t *list, const char *text, lv_event_cb_t event_cb, void *user_data)
+static lv_obj_t *add_menu_list_item(lv_obj_t *list, const char *text, lv_event_cb_t event_cb, void *user_data, SettingsScreenCategory_e category)
 {
     lv_obj_t *btn = lv_list_add_btn(list, NULL, text);
     lv_obj_t *label = lv_obj_get_child(btn, 0);
@@ -721,6 +733,7 @@ static lv_obj_t *add_menu_list_item(lv_obj_t *list, const char *text, lv_event_c
         lv_label_set_long_mode(label, LV_LABEL_LONG_WRAP);
     }
 
+    lv_obj_set_user_data(btn, (void *)category);
     lv_obj_add_event_cb(btn, event_cb, LV_EVENT_CLICKED, user_data);
     return btn;
 }

src/lvgl_win_sim/lv_port_win_codeblocks/settings_screen.h

@@ -8,6 +8,24 @@ typedef struct SettingsScreenAPIInterface
 
 } SettingsScreenAPIInterface_t;
 
+typedef enum SettingsScreenState
+{
+    SETTINGS_SCREEN_STATE_OPENED = 0,
+    SETTINGS_SCREEN_STATE_CLOSED
+} SettingsScreenState_e;
+
+typedef enum SettingsScreenCategory
+{
+    SETTINGS_SCREEN_CATEGORY_TIME_AND_DATE = 0,
+    SETTINGS_SCREEN_CATEGORY_DISPLAY,
+    SETTINGS_SCREEN_CATEGORY_NOTIFICATION,
+    SETTINGS_SCREEN_CATEGORY_CONNECTIVITY,
+    SETTINGS_SCREEN_CATEGORY_LANGUAGE,
+    SETTINGS_SCREEN_CATEGORY_ABOUT,
+} SettingsScreenCategory_e;
+
+typedef void (*SettingsScreenOnStateChangeCb_t)(SettingsScreenState_e settingsScreenState, SettingsScreenCategory_e settingsScreenCategory);
+
 typedef struct SettingsScreen
 {
     SettingsScreenAPIInterface_t settingsScreenAPIInterface;
@@ -64,10 +82,21 @@ typedef struct SettingsScreen
 
     /* Other */
     lv_timer_t *about_refresh_timer;
+    SettingsScreenOnStateChangeCb_t settingsScreenOnStateChangeCb;
 } SettingsScreen_t;
 
 void settings_screen_init(SettingsScreen_t * const settingsScreen);
 
+/**
+ * @brief Registers a callback function which will be called every time the state of the application changes ie : is opened or closed.
+ *        This callback should be used to initialize and deinitialize needed devices drivers like the magnetometer or the temperature sensor.
+ * @note The state of the application is passed as a parameter or the callback function. 
+ * 
+ * @param settingsScreen a pointer to the settings screen object structure.
+ * @param SettingsScreenOnStateChangeCb the callback of type @ref SettingsScreenOnStateChangeCb_t to register.
+ */
+void settings_screen_register_on_state_change_cb(SettingsScreen_t * const settingsScreen, SettingsScreenOnStateChangeCb_t SettingsScreenOnStateChangeCb);
+
 void settings_screen_register_API_interface(SettingsScreen_t * const settingsScreen, SettingsScreenAPIInterface_t * const settingsScreenAPIInterface);
 
 void settings_screen_create(SettingsScreen_t * const settingsScreen);