select control

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Minimal field JSON:

{
  "id": "profile",
  "type": "select",
  "name": "Profile",
  "options": [
    {
      "value": "eco",
      "name": "Economy"
    },
    {
      "value": "comfort",
      "name": "Comfort"
    }
  ]
}

Full field JSON:

{
  "id": "profile",
  "type": "select",
  "name": "Profile",
  "options": [
    {
      "value": "eco",
      "name": "Economy"
    },
    {
      "value": "comfort",
      "name": "Comfort"
    }
  ],
  "default": "eco"
}

Properties in the full example:

Property	Required?	Meaning / default
id	Required	Stable application key; unique across registered pages.
type	Required	Enabled field type.
name	Required title¹	Display title; may be replaced by a nonempty names object.
options	Required	1–16 choices; each has value and name or names.
default	Optional	Omit to use the built-in initial value.

¹ name can be replaced by names. Other shared optional properties are listed in the catalogue.

Appearance: Rounded dropdown with translated option labels

Value: One option's string value

Each option accepts optional names. HA displays labels; discovery templates map those labels to/from stable MQTT values.

Read and update values from C++

These examples use the field ID from the JSON above and an existing ArdPortal portal. Run them after page registration has finished and portal.portalAndAppConfigReady() is true. Call portal.loop() frequently. Register callbacks once in setup(); do not repeat setters on every loop iteration.

Set the value with automatic ArdFS persistence

Set "persist": true on this field in its page JSON. It is optional for editable fields whose preset already persists settings, but required to override a RAM-only preset such as a sensor. Calling setAppConfigValue() sets the control value and ArdPortal automatically saves AppConfig through its integrated ArdFS storage. Do not create an ArdFS object or call a separate write/flush method. The automatic save is coalesced and advanced by subsequent portal.loop() calls.

// Use this path when the value is a setting that should survive restart.
ArdJSON::JSONVar next = "eco";
if (!next.isValid() || !portal.setAppConfigValue("profile", next)) {
  Serial.println("Setting rejected or storage temporarily unavailable");
}

true from the setter means acceptance, not a completed flash write. Configure this callback once to observe the result:

portal.onPortalAndAppConfigSaved([](bool ok, const String& error) {
  if (!ok) Serial.println(error);
});

Update only RAM

// Use this alternative for live readings/status; never writes ArdFS.
ArdJSON::JSONVar next = "eco";
if (!next.isValid() || !portal.setAppConfigStateValue("profile", next, false)) {
  Serial.println("Runtime value rejected");
}

The third argument false avoids queuing an immediate MQTT publication. Use true or omit it to queue changed state. RAM updates work regardless of persist. Alternatively, with "persist": false, setAppConfigValue() also follows the RAM-only path.

Read the current value

const ArdJSON::JSONVar current = portal.getAppConfigValue("profile");
if (!current.isUndefined() && current.isValid()) {
  Serial.println(ArdJSON::JSON.stringify(current));
}

The getter returns the effective field value: RAM override first, then saved AppConfig, then the definition default. A RAM-only update is lost on restart; the saved value/default becomes effective again. Choose the persistent or RAM path for a given value. A RAM override can mask a later persistent change for the same ID; there is no API to clear just that override. Prefer separate setting and telemetry IDs when both are needed.

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