feat(tabview): support getting tab buttons by index

src/others/xml/lv_xml.c

@@ -96,6 +96,7 @@ void lv_xml_init(void)
     lv_xml_widget_register("lv_tabview", lv_xml_tabview_create, lv_xml_tabview_apply);
     lv_xml_widget_register("lv_tabview-tab_bar", lv_xml_tabview_tab_bar_create, lv_xml_tabview_tab_bar_apply);
     lv_xml_widget_register("lv_tabview-tab", lv_xml_tabview_tab_create, lv_xml_tabview_tab_apply);
+    lv_xml_widget_register("lv_tabview-tab_button", lv_xml_tabview_tab_button_create, lv_xml_tabview_tab_button_apply);
     lv_xml_widget_register("lv_chart", lv_xml_chart_create, lv_xml_chart_apply);
     lv_xml_widget_register("lv_chart-cursor", lv_xml_chart_cursor_create, lv_xml_chart_cursor_apply);
     lv_xml_widget_register("lv_chart-series", lv_xml_chart_series_create, lv_xml_chart_series_apply);

src/others/xml/parsers/lv_xml_tabview_parser.c

@@ -87,6 +87,33 @@ void lv_xml_tabview_tab_apply(lv_xml_parser_state_t * state, const char ** attrs
     lv_xml_obj_apply(state, attrs);
 }
 
+void * lv_xml_tabview_tab_button_create(lv_xml_parser_state_t * state, const char ** attrs)
+{
+    lv_obj_t * tv = lv_xml_state_get_parent(state);
+    int32_t btn_cnt = lv_tabview_get_tab_count(tv);
+    if(btn_cnt == 0) {
+        LV_LOG_WARN("There are no buttons on the tab view. Get tab buttons when the tabs are already created");
+        return NULL;
+    }
+
+    const char * index_str = lv_xml_get_value_of(attrs, "index");
+    int32_t index_int = index_str ? lv_xml_atoi(index_str) : 0;
+    if(LV_ABS(index_int) >= btn_cnt) {
+        LV_LOG_WARN("tabindex is out of range, using the first tab instead");
+        index_int = 0;
+    }
+
+    void * item = lv_tabview_get_tab_button(tv, index_int);
+
+    return item;
+}
+
+void lv_xml_tabview_tab_button_apply(lv_xml_parser_state_t * state, const char ** attrs)
+{
+    /*Apply the common properties, e.g. width, height, styles flags etc*/
+    lv_xml_obj_apply(state, attrs);
+}
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/

src/others/xml/parsers/lv_xml_tabview_parser.h

@@ -30,6 +30,8 @@ void * lv_xml_tabview_tab_bar_create(lv_xml_parser_state_t * state, const char *
 void lv_xml_tabview_tab_bar_apply(lv_xml_parser_state_t * state, const char ** attrs);
 void * lv_xml_tabview_tab_create(lv_xml_parser_state_t * state, const char ** attrs);
 void lv_xml_tabview_tab_apply(lv_xml_parser_state_t * state, const char ** attrs);
+void * lv_xml_tabview_tab_button_create(lv_xml_parser_state_t * state, const char ** attrs);
+void lv_xml_tabview_tab_button_apply(lv_xml_parser_state_t * state, const char ** attrs);
 
 /**********************
  *      MACROS

src/widgets/tabview/lv_tabview.c

@@ -242,6 +242,13 @@ uint32_t lv_tabview_get_tab_active(lv_obj_t * obj)
     return tabview->tab_cur;
 }
 
+lv_obj_t * lv_tabview_get_tab_button(lv_obj_t * obj, int32_t idx)
+{
+    LV_ASSERT_OBJ(obj, MY_CLASS);
+
+    return lv_obj_get_child_by_type(lv_tabview_get_tab_bar(obj), idx, &lv_button_class);
+}
+
 uint32_t lv_tabview_get_tab_count(lv_obj_t * obj)
 {
     LV_ASSERT_OBJ(obj, MY_CLASS);

src/widgets/tabview/lv_tabview.h

@@ -88,6 +88,15 @@ uint32_t lv_tabview_get_tab_count(lv_obj_t * obj);
  */
 uint32_t lv_tabview_get_tab_active(lv_obj_t * obj);
 
+/**
+ * Get a given tab button by index
+ * @param obj       pointer to a tabview widget
+ * @param idx       zero based index of the tab button to get.
+ *                  < 0 means start counting tab button from the back (-1 is the last tab button)
+ * @return          pointer to the tab button, or NULL if the index was out of range
+ */
+lv_obj_t * lv_tabview_get_tab_button(lv_obj_t * obj, int32_t idx);
+
 /**
  * Get the widget where the container of each tab is created
  * @param obj       pointer to a tabview widget

xmls/lv_tabview.xml

@@ -16,5 +16,9 @@ Example
         <element name="tab" type="lv_obj" access="add">
             <arg name="text" type="string"/>
         </element>
+        <element name="tab_button" type="lv_obj" access="get">
+            <arg name="index" type="int"/>
+        </element>
+
     </api>
 </widget>