Generic Card

The generic card displays a single value of any supported type together with an optional symbol or unit. Use it for counters, status strings and other values that no dedicated card covers.

ConstructorCopy Anchor Link

dash::GenericCard<T, Precision> card(dashboard, name, symbol);

Template parameters:

dash::GenericCard<int> restarts(dashboard, "Restarts", "times");
dash::GenericCard<float, 3> energy(dashboard, "Energy", "kWh");
dash::GenericCard status(dashboard, "Status"); // dash::string

An overload without the dashboard argument creates the card without attaching it to a dashboard; attach it later with dashboard.add(card).

MethodsCopy Anchor Link

setValue()Copy Anchor Link

bool setValue(const T& value);

Sets the displayed value. Returns true if the value changed and an update is pending, false if the new value equals the current one.

value()Copy Anchor Link

const T& value() const;

Returns the current value. Call it only when hasValue() returns true.

hasValue()Copy Anchor Link

bool hasValue() const;

Returns true if a value has been set.

removeValue()Copy Anchor Link

bool removeValue();

Clears the value. The dashboard then shows 0 for numeric types or an empty string for text types. Returns true if a value was removed.

setSymbol()Copy Anchor Link

bool setSymbol(const char* symbol);

Sets the symbol or unit displayed next to the value. Returns true if the symbol changed.

symbol()Copy Anchor Link

const char* symbol() const;

Returns the current symbol.

ExampleCopy Anchor Link

#include <Arduino.h>
#include <WiFi.h>              // ESP32; use the networking headers for your board
#include <AsyncTCP.h>
#include <ESPAsyncWebServer.h>
#include <ESPDash.h>

AsyncWebServer server(80);
ESPDash dashboard(server);

dash::GenericCard<int> counter(dashboard, "Counter", "events");

int events = 0;

void setup() {
  // ... connect to Wi-Fi
  server.begin();
}

void loop() {
  counter.setValue(++events);
  dashboard.sendUpdates();
  delay(3000);
}

NotesCopy Anchor Link

• The card stores the symbol pointer and does not copy the string. Pass a string literal or a buffer that outlives the card.
• dash::string is Arduino String by default, or std::string when DASH_USE_STL_STRING is defined.