Control slider

slider control

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Minimal field JSON:

{
  "id": "level",
  "type": "slider",
  "name": "Level",
  "min": 0,
  "max": 100
}

Full field JSON:

{
  "id": "level",
  "type": "slider",
  "name": "Level",
  "min": 0,
  "max": 100,
  "step": 1,
  "default": 50
}

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.
min	Required	Lower bound; required for this field type.
max	Required	Upper bound; must be greater than min.
step	Optional	Defaults to 1 for slider or 0.5 for climate.
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: Slider with a live numeric readout

Value: Number

Required min/max; step defaults to 1. The value must lie on the step grid starting at min.

Integration with Home Assistant

MQTT component: number. Requires the control’s feature flag, dynamic pages, MQTT and HA support to be enabled. ArdPortal registers MQTT Discovery and routes state/commands; the sketch implements device behavior. Action callbacks acknowledge acceptance, not physical completion.

Supported by ArdPortal: Numeric state and commands on the field’s base topic; configured min, max and step are advertised. The built-in HA display mode is a slider.

Not provided by the built-in integration / limits: No automatic unit conversion, physical actuator driver, or separate read-only measurement endpoint. Values must satisfy the configured range and step.

Explicit ha properties can override Discovery metadata. They do not create additional hardware behavior, application value properties or command handlers by themselves. See HA integration for the shared setup.

Integration with Zigbee

Native mapping: Analog Output (0x000D). Requires ESP32-C5/C6/H2, ARDPORTAL_ENABLE_ZIGBEE=1, enabled dynamic pages and the control’s feature flag, with the matching End Device/Router board mode. MQTT/HA is not required. Register the initial pages before endpoint startup; later endpoint changes require restart. persist retains its AppConfig meaning.

Supported by ArdPortal: Numeric present value, min/max/resolution attributes and incoming value writes. Range/step checks reuse the field definition.

Not provided / limits: float32 cannot preserve arbitrary double precision. Generic Analog Output may need a gateway converter; creating an endpoint does not guarantee a slider in the gateway UI.

visibleWhen does not dynamically add/remove Zigbee endpoints: they remain registered, and Zigbee commands remain accepted regardless of field visibility. Gateway presentation depends on its support for the mapped clusters. ArdPortal can export a Zigbee2MQTT converter or ZHA quirk; see the validation scope.

See Zigbee integration for pairing, endpoint lifecycle, gateway limitations and OTA requirements.

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 = 50;
if (!next.isValid() || !portal.setAppConfigValue("level", 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 = 50;
if (!next.isValid() || !portal.setAppConfigStateValue("level", 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("level");
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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