feat(obj) Backport keypad and encoder scrolling from v7 lv_page to v8 lv_obj (#2390)

* support scrolling scrollable but non-editable objects thru keypad / encoder

* update doc on `lv_obj` scrolling behavior by arrow keys

docs/widgets/obj.md

@@ -166,7 +166,9 @@ By default, the objects can be clicked only on their coordinates, however, this
 Learn more about [Events](/overview/event).
 
 ## Keys
-If `LV_OBJ_FLAG_CHECKABLE` is enabled `LV_KEY_RIGHT` and `LV_KEY_UP` make the object checked, and `LV_KEY_LEFT` and `LV_KEY_DOWN` make it unchecked.
+If `LV_OBJ_FLAG_CHECKABLE` is enabled, `LV_KEY_RIGHT` and `LV_KEY_UP` make the object checked, and `LV_KEY_LEFT` and `LV_KEY_DOWN` make it unchecked.
+
+If `LV_OBJ_FLAG_SCROLLABLE` is enabled, but the object is not editable (as declared by the widget class), the arrow keys (`LV_KEY_UP`, `LV_KEY_DOWN`, `LV_KEY_LEFT`, `LV_KEY_RIGHT`) scroll the object. If the object can only scroll vertically, `LV_KEY_LEFT` and `LV_KEY_RIGHT` will scroll up/down instead, making it compatible with an encoder input device. See [Input devices overview](/overview/indev) for more on encoder behaviors and the edit mode.
 
 
 Learn more about [Keys](/overview/indev).

src/core/lv_group.c

@@ -251,13 +251,7 @@ lv_res_t lv_group_send_data(lv_group_t * group, uint32_t c)
 {
     lv_obj_t * act = lv_group_get_focused(group);
     if(act == NULL) return LV_RES_OK;
-
+    return lv_event_send(act, LV_EVENT_KEY, &c);
-    lv_res_t res;
-
-    res = lv_event_send(act, LV_EVENT_KEY, &c);
-    if(res != LV_RES_OK) return res;
-
-    return res;
 }
 
 void lv_group_set_focus_cb(lv_group_t * group, lv_group_focus_cb_t focus_cb)

src/core/lv_indev.c

@@ -554,9 +554,9 @@ static void indev_encoder_proc(lv_indev_t * i, lv_indev_data_t * data)
         i->proc.pr_timestamp = lv_tick_get();
 
         if(data->key == LV_KEY_ENTER) {
-            bool editable = lv_obj_is_editable(indev_obj_act);
+            bool editable_or_scrollable = lv_obj_is_editable(indev_obj_act) ||
-
+                                          lv_obj_has_flag(indev_obj_act, LV_OBJ_FLAG_SCROLLABLE);
-            if(lv_group_get_editing(g) == true || editable == false) {
+            if(lv_group_get_editing(g) == true || editable_or_scrollable == false) {
                 lv_event_send(indev_obj_act, LV_EVENT_PRESSED, indev_act);
                 if(indev_reset_check(&i->proc)) return;
             }
@@ -590,12 +590,14 @@ static void indev_encoder_proc(lv_indev_t * i, lv_indev_data_t * data)
             i->proc.longpr_rep_timestamp = lv_tick_get();
 
             if(data->key == LV_KEY_ENTER) {
-                bool editable = lv_obj_is_editable(indev_obj_act);
+                bool editable_or_scrollable = lv_obj_is_editable(indev_obj_act) ||
+                                              lv_obj_has_flag(indev_obj_act, LV_OBJ_FLAG_SCROLLABLE);
 
                 /*On enter long press toggle edit mode.*/
-                if(editable) {
+                if(editable_or_scrollable) {
                     /*Don't leave edit mode if there is only one object (nowhere to navigate)*/
                     if(lv_group_get_obj_count(g) > 1) {
+                        LV_LOG_INFO("toggling edit mode");
                         lv_group_set_editing(g, lv_group_get_editing(g) ? false : true); /*Toggle edit mode on long press*/
                         lv_obj_clear_state(indev_obj_act, LV_STATE_PRESSED);    /*Remove the pressed state manually*/
                     }
@@ -639,10 +641,11 @@ static void indev_encoder_proc(lv_indev_t * i, lv_indev_data_t * data)
         LV_LOG_INFO("released");
 
         if(data->key == LV_KEY_ENTER) {
-            bool editable = lv_obj_is_editable(indev_obj_act);
+            bool editable_or_scrollable = lv_obj_is_editable(indev_obj_act) ||
+                                          lv_obj_has_flag(indev_obj_act, LV_OBJ_FLAG_SCROLLABLE);
 
             /*The button was released on a non-editable object. Just send enter*/
-            if(editable == false) {
+            if(editable_or_scrollable == false) {
                 lv_event_send(indev_obj_act, LV_EVENT_RELEASED, indev_act);
                 if(indev_reset_check(&i->proc)) return;
 
@@ -674,7 +677,8 @@ static void indev_encoder_proc(lv_indev_t * i, lv_indev_data_t * data)
             }
             /*If the focused object is editable and now in navigate mode then on enter switch edit
                mode*/
-            else if(editable && !lv_group_get_editing(g) && !i->proc.long_pr_sent) {
+            else if(!i->proc.long_pr_sent) {
+                LV_LOG_INFO("entering edit mode");
                 lv_group_set_editing(g, true); /*Set edit mode*/
             }
         }
@@ -686,9 +690,9 @@ static void indev_encoder_proc(lv_indev_t * i, lv_indev_data_t * data)
 
     /*if encoder steps or simulated steps via left/right keys*/
     if(data->enc_diff != 0) {
-        LV_LOG_INFO("rotated by %d", data->enc_diff);
         /*In edit mode send LEFT/RIGHT keys*/
         if(lv_group_get_editing(g)) {
+            LV_LOG_INFO("rotated by %+d (edit)", data->enc_diff);
             int32_t s;
             if(data->enc_diff < 0) {
                 for(s = 0; s < -data->enc_diff; s++) lv_group_send_data(g, LV_KEY_LEFT);
@@ -699,6 +703,7 @@ static void indev_encoder_proc(lv_indev_t * i, lv_indev_data_t * data)
         }
         /*In navigate mode focus on the next/prev objects*/
         else {
+            LV_LOG_INFO("rotated by %+d (nav)", data->enc_diff);
             int32_t s;
             if(data->enc_diff < 0) {
                 for(s = 0; s < -data->enc_diff; s++) lv_group_focus_prev(g);

src/core/lv_obj.c

@@ -702,6 +702,34 @@ static void lv_obj_event(const lv_obj_class_t * class_p, lv_event_t * e)
                 if(res != LV_RES_OK) return;
             }
         }
+        else if(lv_obj_has_flag(obj, LV_OBJ_FLAG_SCROLLABLE) && !lv_obj_is_editable(obj)) {
+            /*scroll by keypad or encoder*/
+            lv_anim_enable_t anim_enable = LV_ANIM_OFF;
+            lv_coord_t sl = lv_obj_get_scroll_left(obj);
+            lv_coord_t sr = lv_obj_get_scroll_right(obj);
+            char c = *((char *)lv_event_get_param(e));
+            if(c == LV_KEY_DOWN) {
+                /*use scroll_to_x/y functions to enforce scroll limits*/
+                lv_obj_scroll_to_y(obj, lv_obj_get_scroll_y(obj) + lv_obj_get_height(obj) / 4, anim_enable);
+            }
+            else if(c == LV_KEY_UP) {
+                lv_obj_scroll_to_y(obj, lv_obj_get_scroll_y(obj) - lv_obj_get_height(obj) / 4, anim_enable);
+            }
+            else if(c == LV_KEY_RIGHT) {
+                /*If the object can't be scrolled horizontally then scroll it vertically*/
+                if(!((lv_obj_get_scroll_dir(obj) & LV_DIR_HOR) && (sl > 0 || sr > 0)))
+                    lv_obj_scroll_to_y(obj, lv_obj_get_scroll_y(obj) + lv_obj_get_height(obj) / 4, anim_enable);
+                else
+                    lv_obj_scroll_to_x(obj, lv_obj_get_scroll_x(obj) + lv_obj_get_width(obj) / 4, anim_enable);
+            }
+            else if(c == LV_KEY_LEFT) {
+                /*If the object can't be scrolled horizontally then scroll it vertically*/
+                if(!((lv_obj_get_scroll_dir(obj) & LV_DIR_HOR) && (sl > 0 || sr > 0)))
+                    lv_obj_scroll_to_y(obj, lv_obj_get_scroll_y(obj) - lv_obj_get_height(obj) / 4, anim_enable);
+                else
+                    lv_obj_scroll_to_x(obj, lv_obj_get_scroll_x(obj) - lv_obj_get_width(obj) / 4, anim_enable);
+            }
+        }
     }
     else if(code == LV_EVENT_FOCUSED) {
         if(lv_obj_has_flag(obj, LV_OBJ_FLAG_SCROLL_ON_FOCUS)) {