Add ItemValue class for dynamic value display

- Introduced a new template class to create menu items that display values.
- Added polling functionality to update the menu at regular intervals.
- Updated LcdMenu and MenuScreen classes to support polling.
- Defined ITEM_VALUE macro for easy item creation with formatting options.

src/ItemValue.h

@@ -0,0 +1,55 @@
+#pragma once
+
+#include "BaseItemZeroWidget.h"
+
+/**
+ * @class ItemValue
+ * @brief A menu item that displays a value.
+ *
+ * This class extends the BaseItemZeroWidget class and provides a menu item
+ * that displays a value. The value is provided as a reference during construction
+ * and is displayed using the provided format string.
+ */
+template <typename T>
+class ItemValue : public BaseItemZeroWidget {
+  private:
+    T& value;
+    const char* format;
+
+  public:
+    ItemValue(const char* text, T& value, const char* format) : BaseItemZeroWidget(text), value(value), format(format) {
+        this->polling = true;
+    }
+
+  protected:
+    void handleCommit(LcdMenu* menu) override {}
+
+    void draw(MenuRenderer* renderer) override {
+        char buffer[ITEM_DRAW_BUFFER_SIZE];
+        snprintf(buffer, ITEM_DRAW_BUFFER_SIZE, format, value);
+        renderer->drawItem(text, buffer);
+    }
+};
+
+/**
+ * @brief Create a new item that displays a value.
+ * @note If you want to display a value that changes over time, use this item and
+ *       call `LcdMenu::poll` in the loop function.
+ *
+ * @tparam T the type of the value to display
+ * @param text the text to display for the item
+ * @param value the value to display
+ * @param format the format string to use when displaying the value
+ * @return MenuItem* the created item
+ *
+ * @example
+ *   int temp = 25;
+ *   auto item = ITEM_VALUE("Temperature", temp, "%d°C");
+ */
+template <typename T>
+inline MenuItem* ITEM_VALUE(
+    const char* text,
+    T& value,
+    const char* format = "%s") {
+    return new ItemValue<T>(text, value, format);
+}

src/LcdMenu.cpp

@@ -64,3 +64,10 @@ void LcdMenu::refresh() {
     }
     screen->draw(&renderer);
 }
+
+void LcdMenu::poll(uint16_t pollInterval) {
+    if (!enabled || pollInterval == 0) {
+        return;
+    }
+    screen->poll(&renderer, pollInterval < 100 ? 100 : pollInterval);
+}

src/LcdMenu.h

@@ -120,4 +120,13 @@ class LcdMenu {
      * @brief Refresh the current screen.
      */
     void refresh();
+    /**
+     * @brief Poll the menu for changes.
+     *        This method is used to update the menu at regular intervals,
+     *        for example, when a value bound to an item changes, the menu needs to be updated.
+     *        This method should be called in the `loop` function of the sketch.
+     *
+     * @param pollInterval the interval to update the menu in milliseconds (default is 1000)
+     */
+    void poll(uint16_t pollInterval = 1000);
 };

src/MenuItem.h

@@ -27,6 +27,8 @@
 #ifndef MenuItem_H
 #define MenuItem_H
 
+#define ITEM_DRAW_BUFFER_SIZE 25
+
 #include "renderer/MenuRenderer.h"
 #include "utils/constants.h"
 #include <utils/utils.h>
@@ -49,6 +51,7 @@ class MenuItem {
 
   protected:
     const char* text = NULL;
+    bool polling = false;
 
   public:
     MenuItem(const char* text) : text(text) {}

src/MenuScreen.cpp

@@ -115,4 +115,17 @@ MenuScreen::MenuScreen(MenuItem** items) : items(items) {
     while (items[itemCount] != nullptr) {
         itemCount++;
     }
+}
+
+void MenuScreen::poll(MenuRenderer* renderer, uint16_t pollInterval) {
+    static unsigned long lastPollTime = 0;
+    if (millis() - lastPollTime >= pollInterval) {
+        for (uint8_t i = 0; i < renderer->maxRows; i++) {
+            MenuItem* item = this->items[view + i];
+            if (item == nullptr || !item->polling) break;
+            syncIndicators(i, renderer);
+            item->draw(renderer);
+        }
+        lastPollTime = millis();
+    }
 }

src/MenuScreen.h

@@ -124,6 +124,12 @@ class MenuScreen {
      * @brief Reset the screen to initial state.
      */
     void reset(MenuRenderer* renderer);
+    /**
+     * @brief Poll the screen for changes.
+     * @param renderer The renderer to use for drawing.
+     * @param pollInterval The interval to poll the screen.
+     */
+    void poll(MenuRenderer* renderer, uint16_t pollInterval);
 };
 
 #define MENU_SCREEN(screen, items, ...)         \

src/widget/BaseWidget.h

@@ -7,8 +7,6 @@
 #endif
 #endif
 
-#define ITEM_DRAW_BUFFER_SIZE 25
-
 class LcdMenu;
 
 /**