Unable to set value to RangeWidget

[ZatopkosAdamos]

Hello, iam doing school project and iam mostly done with LCD screen and control. But for last 5 hours iam trying to find how to save and load default values in/from EEPROM for first WIDGET_RANGE, and WIDGET_RANGE in second line, that are inside ITEM_WIDGET
If i understood correctly, i cannot just load from EEPROM into CARRIAGE_WEIGHT variable in Setup(). So iam trying to find i way how to change the first (default) value in WidgetRange in ItemWidget later in the code. I found out i probably need something like targeting the widgetRange and use setValue to change it, and then just refresh screen. I was trying a lot combinations and this seemed to me like i was closest to getting it, but i just cannot understand the errors its giving me. Can I ask the community for help as iam lost. Thanks.

MENU_SCREEN(mainScreen, mainItems,
    ITEM_WIDGET("Weight",CarriageWeightCallback, WIDGET_RANGE(CARRIAGE_WEIGHT, 0.01f, 0.0f, MAX_CARRIAGE_WEIGHT, "%.2f Kg", 3, true)),
    ITEM_WIDGET("Energy",EnergyCallback, WIDGET_RANGE(LIFT_ENERGY, 0.01f, 0.0f, MAX_LIFT_ENERGY, "%.2f J", 3, true)),
    ITEM_VALUE("Height",LIFT_HEIGHT_text,"%s"),
    ITEM_VALUE("=Speed", DROP_T_SPEED, "%.2f m/s"));

Setup()
    float valueFromEEPROM = 0.05;
    (static_cast<ItemWidget*>(widgetPtrs[0]))->setValue(NewValue);
    menu.refresh();

Error from this approach is: Compilation error: invalid use of template-name 'ItemWidget' without an argument list

[fvdbeek]

I struggled with the same problem. ITEM_WIDGET is a class template and the class should be created with the type in angle brackets. The method to set the values of ITEM_WIDGET is setValues instead of setValue. In my project, I use WIDGET_RANGE to change the backlight brightness of the LCD:

ItemWidget<int>* widget_ptr;
int brightness;
void brightness_callback(const int& value);

MENU_SCREEN(main_screen, main_items,
            ITEM_WIDGET(
                "Brightness", nullptr,
                WIDGET_RANGE(brightness, 16, 0, 256, "%u", 0, true, brightness_callback)));

void setup() {
  brightness = 128;
  pinMode(LCD_BACKLIGHT, OUTPUT);
  analogWrite(LCD_BACKLIGHT, brightness);
  renderer.begin();
  menu.setScreen(main_screen);
  widget_ptr = static_cast<ItemWidget<int>*>(main_screen->getItemAt(0));
  widget_ptr->setValues(brightness);
  menu.refresh();
}

void brightness_callback(const int& value) {
  // the maximum value of PWM is 255
  brightness = min(value, 255);
  analogWrite(LCD_BACKLIGHT, brightness);
}

[ShishkinDmitriy]

Hi, you can use assign ITEM_WIDGET directly to variable:

int brightness;
void brightness_callback(const int& value);
ItemWidget<int>* widget_ptr = ITEM_WIDGET(
                "Brightness", nullptr,
                WIDGET_RANGE(brightness, 16, 0, 256, "%u", 0, true, brightness_callback));

MENU_SCREEN(main_screen, main_items,
            widget_ptr);

void setup() {
  brightness = 128;
  // ...
  // no need this:
  // widget_ptr = static_cast<ItemWidget<int>*>(main_screen->getItemAt(0));
  widget_ptr->setValues(brightness);
  menu.refresh();
}

Also note that both Item and Widget have callbacks and for this example they have same signature and may be confising.
The item's callback behaves as onCommit callbcak and will be called only after you change value and ENTER
The widget's callback behaves as onChange callback and is called on any change.