feat(event) add lv_obj_remove_event_cb_with_user_data

fixes #2459

src/core/lv_event.c

@@ -170,7 +170,7 @@ bool lv_obj_remove_event_cb(lv_obj_t * obj, lv_event_cb_t event_cb)
 
     int32_t i = 0;
     for(i = 0; i < obj->spec_attr->event_dsc_cnt; i++) {
-        if(obj->spec_attr->event_dsc[i].cb == event_cb) {
+        if(event_cb == NULL || obj->spec_attr->event_dsc[i].cb == event_cb) {
             /*Shift the remaining event handlers forward*/
             for(; i < (obj->spec_attr->event_dsc_cnt-1); i++) {
                 obj->spec_attr->event_dsc[i] = obj->spec_attr->event_dsc[i+1];
@@ -186,6 +186,32 @@ bool lv_obj_remove_event_cb(lv_obj_t * obj, lv_event_cb_t event_cb)
     return false;
 }
 
+bool lv_obj_remove_event_cb_with_user_data(lv_obj_t * obj, lv_event_cb_t event_cb, const void * user_data)
+{
+    LV_ASSERT_OBJ(obj, MY_CLASS);
+    if(obj->spec_attr == NULL) return false;
+
+    int32_t i = 0;
+    for(i = 0; i < obj->spec_attr->event_dsc_cnt; i++) {
+        if((event_cb == NULL || obj->spec_attr->event_dsc[i].cb) &&
+                obj->spec_attr->event_dsc[i].user_data == user_data)
+        {
+            /*Shift the remaining event handlers forward*/
+            for(; i < (obj->spec_attr->event_dsc_cnt-1); i++) {
+                obj->spec_attr->event_dsc[i] = obj->spec_attr->event_dsc[i+1];
+            }
+            obj->spec_attr->event_dsc_cnt--;
+            obj->spec_attr->event_dsc = lv_mem_realloc(obj->spec_attr->event_dsc, obj->spec_attr->event_dsc_cnt * sizeof(lv_event_dsc_t));
+            LV_ASSERT_MALLOC(obj->spec_attr->event_dsc);
+            return true;
+        }
+    }
+
+    /*No event handler found*/
+    return false;
+}
+
+
 bool lv_obj_remove_event_dsc(lv_obj_t * obj, struct _lv_event_dsc_t * event_dsc)
 {
     LV_ASSERT_OBJ(obj, MY_CLASS);

src/core/lv_event.h

@@ -214,12 +214,22 @@ struct _lv_event_dsc_t * lv_obj_add_event_cb(struct _lv_obj_t * obj, lv_event_cb
 /**
  * Remove an event handler function for an object.
  * @param obj       pointer to an object
- * @param event_cb  the event function to remove
+ * @param event_cb  the event function to remove, or `NULL` to remove the the firstly added event callback
  * @return          true if any event handlers were removed
  */
 bool lv_obj_remove_event_cb(struct _lv_obj_t * obj, lv_event_cb_t event_cb);
 
 /**
+ * Remove an event handler function with a specific user_data from an object.
+ * @param obj       pointer to an object
+ * @param event_cb  the event function to remove, or `NULL` only `user_data` matters.
+ * @param user_data the user_data specified in ::lv_obj_add_event_cb
+ * @return          true if any event handlers were removed
+ */
+bool lv_obj_remove_event_cb_with_user_data(struct _lv_obj_t * obj, lv_event_cb_t event_cb, const void * user_data);
+
+/**
+ * DEPRACTED because doesn't work if multiple event handlers are added to an object.
  * Remove an event handler function for an object.
  * @param obj       pointer to an object
  * @param event_dsc pointer to an event descriptor to remove (returned by ::lv_obj_add_event_cb)