It is now possible to swipe from right to left on the menu screen to open back the previously used application

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

@@ -8,8 +8,6 @@
 #include "music_player_screen.h"
 #include "translation.h"
 
-#define array_size(array) (sizeof(array)/sizeof(array[0]))
-
 static void item_container_scroll_event_cb(lv_event_t *e)
 {
     lv_obj_t * item_container = lv_event_get_target(e);
@@ -32,41 +30,30 @@ static void item_container_scroll_event_cb(lv_event_t *e)
         lv_coord_t diff_y = child_y_center - cont_y_center;
         diff_y = LV_ABS(diff_y);
 
-        /*Get the x of diff_y on a circle.*/
+        // Get the x of diff_y on a circle.
         lv_coord_t x;
-        /*If diff_y is out of the circle use the last point of the circle (the radius)*/
+        // If diff_y is out of the circle use the last point of the circle (the radius)
         if(diff_y >= r)
         {
             x = r;
         }
         else
         {
-            /*Use Pythagoras theorem to get x from radius and y*/
+            // Use Pythagoras theorem to get x from radius and y
             uint32_t x_sqr = r * r - diff_y * diff_y;
             lv_sqrt_res_t res;
             lv_sqrt(x_sqr, &res, 0x8000);   /*Use lvgl's built in sqrt root function*/
             x = r - res.i;
         }
 
-        /*Translate the item by the calculated X coordinate*/
+        // Translate the item by the calculated X coordinate
         lv_obj_set_style_translate_x(child, x, 0);
     }
 }
 
-static void menu_item_cb(lv_event_t *e)
+static void simulate_menu_item_click(uint8_t menu_item_id)
 {
-    lv_obj_t *item = lv_event_get_target(e);
+    switch(menu_item_id)
-    uint32_t clicked_item_id = (uint32_t) lv_obj_get_user_data(item);
-    MenuScreen_t *menuScreen = (MenuScreen_t*) lv_event_get_user_data(e);
-
-    LV_LOG_USER("Menu item clicked : %u", clicked_item_id);
-
-    // Give some user feedback that an item was clicked by calling the
-    // callback if one is registered
-    if(menuScreen->menuScreenOnMenuItemClickCb)
-        menuScreen->menuScreenOnMenuItemClickCb();
-
-    switch(clicked_item_id)
     {
     case 0:
         {
@@ -108,9 +95,45 @@ static void menu_item_cb(lv_event_t *e)
     }
 }
 
+static void menu_item_cb(lv_event_t *e)
+{
+    lv_obj_t *item = lv_event_get_target(e);
+    uint32_t clicked_item_id = (uint32_t) lv_obj_get_user_data(item);
+    MenuScreen_t *menuScreen = (MenuScreen_t*) lv_event_get_user_data(e);
+
+    LV_LOG_USER("Menu item clicked : %u", clicked_item_id);
+
+    menuScreen->lastClickedMenuItem = clicked_item_id;
+
+    // Give some user feedback that an item was clicked by calling the
+    // callback if one is registered
+    if(menuScreen->menuScreenUserFeedbackCb)
+        menuScreen->menuScreenUserFeedbackCb();
+
+    // Switch application depending on the clicked menu item id
+    simulate_menu_item_click(clicked_item_id);
+}
+
+static void gesture_event_cb(lv_event_t *e)
+{
+    MenuScreen_t *menuScreen = lv_event_get_user_data(e);
+
+    lv_dir_t gesture;
+    switch(gesture = lv_indev_get_gesture_dir(lv_indev_get_act()))
+    {
+    case LV_DIR_LEFT:
+        LV_LOG_USER("GESTURE : LEFT");
+        // Go back to the previously clicked application
+        simulate_menu_item_click(menuScreen->lastClickedMenuItem);
+        break;
+    default:
+        LV_LOG_USER("GESTURE : %u", gesture);
+    }
+}
+
 static void cleanup_event_cb(lv_event_t * e)
 {
-    MenuScreen_t *menuScreen = e->user_data;
+    MenuScreen_t *menuScreen = lv_event_get_user_data(e);
     menu_screen_destroy(menuScreen);
     LV_LOG_USER("cleanup");
 }
@@ -125,7 +148,7 @@ void menu_screen_init(MenuScreen_t * const menuScreen)
     memset(menuScreen, 0, sizeof(MenuScreen_t));
 }
 
-void menu_screen_register_on_menu_item_click_cb(MenuScreen_t * const menuScreen, MenuScreenOnMenuItemClickCb_t menuScreenOnMenuItemClickCb)
+void menu_screen_register_user_feedback_cb(MenuScreen_t * const menuScreen, MenuScreenUserFeedbackCb_t menuScreenUserFeedbackCb)
 {
     if(!menuScreen)
     {
@@ -133,7 +156,7 @@ void menu_screen_register_on_menu_item_click_cb(MenuScreen_t * const menuScreen,
         return;
     }
 
-    menuScreen->menuScreenOnMenuItemClickCb = menuScreenOnMenuItemClickCb;
+    menuScreen->menuScreenUserFeedbackCb = menuScreenUserFeedbackCb;
 }
 
 static void menu_screen_add_item(MenuScreen_t * const menuScreen, uint8_t position, const lv_img_dsc_t *itemImg,const char *itemTitle, lv_event_cb_t itemClickEventCb)
@@ -223,9 +246,8 @@ void menu_screen_create(MenuScreen_t * const menuScreen)
     menu_screen_add_item(menuScreen, 5, &watch_menu_dialer_icon, "Phone", &(menu_item_cb));
     menu_screen_add_item(menuScreen, 6, &watch_menu_contacts_icon, "Contacts", &(menu_item_cb));*/
     menu_screen_add_item(menuScreen, 5, &watch_menu_settings_icon, translation_get_word(TRANSLATION_SETTINGS), &(menu_item_cb));
-
+    // We register the event callback to handle the right to left swipe gesture
-    //Lets restore the previous scrolling position
+    lv_obj_add_event_cb(menuScreen->display, &(gesture_event_cb), LV_EVENT_GESTURE, menuScreen);
-    lv_obj_scroll_to_y(menuScreen->scrollItemContainer, menuScreen->lastScrollPosition, LV_ANIM_OFF);
 
     // We register the event callback to handle the cleanup
     lv_obj_add_event_cb(menuScreen->display, &(cleanup_event_cb), LV_EVENT_DELETE, menuScreen);

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

@@ -3,7 +3,7 @@
 
 #include "lvgl.h"
 
-typedef void (*MenuScreenOnMenuItemClickCb_t)(void);
+typedef void (*MenuScreenUserFeedbackCb_t)(void);
 
 // Menu screen context object
 typedef struct MenuScreen
@@ -13,24 +13,40 @@ typedef struct MenuScreen
     lv_obj_t *scrollItemContainer;
     // Should not be erased attributes
     lv_coord_t lastScrollPosition;
-    MenuScreenOnMenuItemClickCb_t menuScreenOnMenuItemClickCb;
+    MenuScreenUserFeedbackCb_t menuScreenUserFeedbackCb;
+    uint8_t lastClickedMenuItem;
 } MenuScreen_t;
 
-/* Initializes the menu screen context object */
+/**
+ * @brief Initializes the menu screen's context object.
+ * @note This function has to be called first before any others.
+ *  
+ * @param menuScreen a pointer to the menu screen's context structure to initialize.
+ */
 void menu_screen_init(MenuScreen_t * const menuScreen);
 
 /**
- * @brief 
+ * @brief Registers a callback functions which will be called every time a user feedback should
+ *        be made. In this case, every time a menu item is clicked, the callback will be called.
+ *        This enables the app to react to this user event.
  * 
- * @param menuScreen 
+ * @param menuScreen a pointer to the previously initialized menu screen's context structure.
- * @param menuScreenOnMenuItemClickCb 
+ * @param menuScreenUserFeedbackCb a pointer to a function having the following signature : void(void).
  */
-void menu_screen_register_on_menu_item_click_cb(MenuScreen_t * const menuScreen, MenuScreenOnMenuItemClickCb_t menuScreenOnMenuItemClickCb);
+void menu_screen_register_user_feedback_cb(MenuScreen_t * const menuScreen, MenuScreenUserFeedbackCb_t menuScreenUserFeedbackCb);
 
-/* Builds the menu screen graphically  */
+/**
+ * @brief Graphically builds the menu screen.
+ * 
+ * @param menuScreen a pointer to the previously initialized menu screen's context structure.
+ */
 void menu_screen_create(MenuScreen_t * const menuScreen);
 
-/* Frees all resources used by the MenuScreen object */
+/**
+ * @brief Frees all resources (GUI and others) used by the MenuScreen_t object.
+ * 
+ * @param menuScreen a pointer to the previously initialized menu screen's context structure.
+ */
 void menu_screen_destroy(MenuScreen_t * const menuScreen);
 
 #endif //MENU_SCREEN_H