RemoteParameter QML Type

Binds to a parameter of another ROS 2 node as desired state. More...

• List of all members, including inherited members

Properties

• autoApply : bool
• name : string
• pending : bool
• ready : bool
• remoteNode : string
• reported : var
• value : var

Signals

• setFailed(string reason)

Methods

• void apply()
• void refresh()

Detailed Description

RemoteParameter is the client side of Parameter (or of any ROS 2 node's parameter): value expresses the desired value, reported tracks what the remote node actually holds.

Node {
    nodeName: "twin"
    RemoteParameter {
        id: masterVolume
        remoteNode: "/dogzilla/dogzilla"
        name: "audio.master"
        value: volumeSlider.value
    }
}
// display: text: `${Math.round(masterVolume.reported * 100)}%`

Writing (or binding) value schedules a coalesced set of the remote parameter: multiple changes per event-loop iteration collapse into one request, changes made while the remote node is unavailable or a request is in flight are remembered, and the latest value is applied as soon as possible — the binding behaves like desired state that is reconciled with the remote node. A set the remote rejects (range violation, unknown parameter, read-only) emits setFailed and is not retried.

reported holds the remote node's actual value: fetched once when the remote parameter services become ready, then tracked via the global /parameter_events topic. It is undefined while unknown and after the remote parameter is deleted.

Property Documentation

autoApply : bool

If true (the default), changes of value are applied automatically. If false, writes only store the value; call apply() explicitly, or enable autoApply to dispatch the most recent stored value — gating autoApply gates dispatch, not intent.

name : string

The parameter name on the remote node.

pending : bool

Read-only: true while a set request is in flight.

ready : bool

Read-only: true while the remote node's parameter services are available on the graph.

remoteNode : string

The fully-qualified name of the remote node (e.g. "/dogzilla/dogzilla"). A relative name is resolved against the local node's namespace.

reported : var

Read-only: the value the remote node actually holds — initial fetch plus updates from /parameter_events. undefined while unknown.

value : var

The desired parameter value. When autoApply is true (the default), each change schedules a coalesced set request; latest-wins reconciliation applies it as soon as the remote node is reachable and no other request is in flight.

Signal Documentation

setFailed(string reason)

Emitted when the remote node rejected a set request or it could not be delivered; reason describes why (range violation, undeclared parameter, read-only). The rejected value is not retried.

Method Documentation

void apply()

Sends the current value to the remote node, regardless of autoApply (still deferred until ready if the remote is unavailable).

void refresh()

Re-fetches reported from the remote node.