Add support for read-only parameters by julianoes · Pull Request #14007 · mavlink/qgroundcontrol

julianoes · 2026-02-19T17:59:28Z

Description

This parses the readonly flag for a parameter, so that it's clear in the UI when a param can't be set.

Type of Change

Bug fix (non-breaking change that fixes an issue)
New feature (non-breaking change that adds functionality)
Breaking change (fix or feature that would cause existing functionality to change)
Documentation update
Refactoring (no functional changes)
CI/Build changes
Other

Testing

Tested locally
Added/updated unit tests
Tested with simulator (SITL)
Tested with hardware

Platforms Tested

Flight Stacks Tested

PX4
ArduPilot

Screenshots

Checklist

I have read the Contribution Guidelines
I have read the Code of Conduct
My code follows the project's coding standards
I have added tests that prove my fix/feature works
New and existing unit tests pass locally

Related Issues

Goes together with PX4/PX4-Autopilot#26522.

By submitting this pull request, I confirm that my contribution is made under the terms of the project's dual license (Apache 2.0 and GPL v3).

github-actions · 2026-02-19T18:09:05Z

Build Results

Platform Status

Platform	Status	Details
Linux	Passed	View
Windows	Passed	View
MacOS	Passed	View
Android	Passed	View

All builds passed.

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Check	Status	Details
pre-commit	Failed (non-blocking)	View

Pre-commit hooks: 4 passed, 36 failed, 7 skipped.

Test Results

linux-coverage: 78 passed, 0 skipped
linux-sanitizers: 78 passed, 0 skipped
Total: 156 passed, 0 skipped

Code Coverage

Coverage: 58.2%

No baseline available for comparison

Artifact Sizes

Artifact	Size
QGroundControl	247.79 MB
QGroundControl-aarch64	177.24 MB
QGroundControl-installer-AMD64	134.84 MB
QGroundControl-installer-AMD64-ARM64	77.44 MB
QGroundControl-installer-ARM64	106.17 MB
QGroundControl-linux	338.32 MB
QGroundControl-mac	188.81 MB
QGroundControl-windows	188.82 MB
QGroundControl-x86_64	172.36 MB
No baseline available for comparison

_{Updated: 2026-04-14 23:15:49 UTC • Triggered by: Android}

julianoes · 2026-02-20T01:40:00Z

Added a commit to display a lock and add a checkbox to filter them out.

hamishwillee · 2026-02-20T07:21:12Z

That is very cool. I'm slightly surprised it doesn't already exist since ArduPilot support read only params

julianoes · 2026-02-20T18:30:55Z

I need to check how read only params work in ArduPilot then, so this is compatible.

hamishwillee · 2026-02-22T21:56:54Z

I need to check how read only params work in ArduPilot then, so this is compatible.

Indeed! Though if they don't have an icon like this then they would probably appreciate one :-)

julianoes · 2026-02-23T01:45:02Z

@hamishwillee from my research I don't see how AP would be communicating this to QGC. I think we can leave this PR as is.

hamishwillee · 2026-02-24T22:42:18Z

Cool. I have no more comments. I guess get Don or Holden to look at it now.

Ryanf55 · 2026-03-03T17:59:09Z

FWIW, ArduPilot likes OEM's to use this script.
https://github.com/ArduPilot/ardupilot/blob/master/libraries/AP_Scripting/applets/param-set.lua

Copilot

Pull request overview

This PR adds end-to-end support for “read-only” parameter metadata so the Parameter UI can indicate non-editable parameters and optionally hide them from the list.

Changes:

Parse a new readOnly boolean from parameter metadata JSON into FactMetaData.
Update the parameter editor dialog to show read-only messaging and prevent editing/saving.
Add UI affordances: a lock icon in the parameter list and a “Hide read-only” filter wired through ParameterEditorController.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/QmlControls/ParameterEditorDialog.qml	Disables editing for read-only facts, shows read-only messaging/value-only display.
src/QmlControls/ParameterEditorController.h	Adds `hideReadOnly` property/signal/slot to support filtering.
src/QmlControls/ParameterEditorController.cc	Implements read-only filtering in list build/search and rebuilds lists on toggle.
src/QmlControls/ParameterEditor.qml	Adds “Hide read-only” checkbox and displays a lock icon for read-only facts in the table.
src/FactSystem/FactMetaData.h	Adds JSON key constant for `readOnly`.
src/FactSystem/FactMetaData.cc	Parses `readOnly` from JSON metadata.

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DonLakeFlyer · 2026-03-19T15:18:32Z

    }
-    metaData->setVolatileValue(volatileValue);

+    if (json.contains(_readOnlyJsonKey)) {


This screws up the positioning of the setVolatileValue with the rest of it's code. Also it doesn't follow the pattern and the rest of the value setting. It should do it the same way as the others.

DonLakeFlyer · 2026-03-19T15:21:17Z

FWIW, ArduPilot likes OEM's to use this script.

For what?

DonLakeFlyer · 2026-03-19T15:22:03Z

Other question: Did the NCELLS param suddenly become ready only. That is part of Power Setup page as something user should set.

DonLakeFlyer · 2026-03-19T15:29:36Z

Code review notes:

1. onAccepted still fires for read-only parameters (ParameterEditorDialog.qml)

The dialog uses Dialog.Close for read-only facts, but the onAccepted handler doesn't guard against writes. If Close ever triggers accepted, the handler would attempt to write to a read-only fact. Consider adding an early return:

onAccepted: {
    if (fact.readOnly) return
    ...
}

2. _hideReadOnlyChanged duplicates _buildLists teardown logic (ParameterEditorController.cc)

The _hideReadOnlyChanged method manually clears _currentCategory, _currentGroup, _parameters, _mapCategoryName2Category, and calls _categories.clearAndDeleteContents() — this is the same teardown that _buildLists() already does internally. This duplication is fragile; if _buildLists teardown changes, this code won't stay in sync. Consider extracting a _clearLists() helper, or just calling _buildLists() directly since it already handles the full rebuild.

julianoes · 2026-03-27T20:35:53Z

Other question: Did the NCELLS param suddenly become ready only. That is part of Power Setup page as something user should set.

No, that's just one that I tried. No param is read only by default. It's just a feature that a drone manufacturer can use.

DonLakeFlyer · 2026-03-29T17:25:42Z

ArduPilot has read only support in their json metadata. This should be carried through to updating the COMPONENT_INFORMATION spec to add read only metadata as well.

hamishwillee · 2026-03-29T21:40:14Z

ArduPilot has read only support in their json metadata. This should be carried through to updating the COMPONENT_INFORMATION spec to add read only metadata as well.

I think so too, but we do need to be careful in case read-only might potentially be a dynamic field, or depend on "who you are".

DonLakeFlyer · 2026-03-30T15:13:48Z

mavlink/mavlink#2449

julianoes · 2026-04-09T01:10:50Z

Alright I've just merged the MAVLink PR, thanks for that @DonLakeFlyer. And I've also rebased the PX4 commit, so that it can hopefully go in soon.

And I've just rebased this and addressed the review comments.

This is how it looks like, and the lock is only displayed for readOnly params, but not for volatile ones:

DonLakeFlyer · 2026-04-14T09:24:22Z

My thinking is that the lock icon should go after the param name not before. I think this makes things more readable when you scan down the names.

This parses the readonly flag for a parameter, so that it's clear in the UI when a param can't be set.

Show a lock icon next to read-only parameter names in the parameter list and add a "Hide read-only" checkbox to filter them out entirely.

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

- Add readOnly guard in ParameterEditorDialog onAccepted handler - Make readOnly JSON parsing follow the same pattern as other bools - Parse readOnly before volatile so setVolatileValue can enforce readOnly - Move teardown logic into _buildLists to avoid duplication in _hideReadOnlyChanged

- Remove _readOnly = true from setVolatileValue() since volatile params (e.g. calibration offsets) should still be user-writable - Fix description column width being cut off due to wrong implicitWidth - Fix QML warning about assigning Fact to QString in name column

julianoes · 2026-04-14T22:17:46Z

Ok, changed:

github-actions bot added the QML label Feb 19, 2026

julianoes mentioned this pull request Feb 19, 2026

feat(params): add board-level read-only parameter support PX4/PX4-Autopilot#26522

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github-actions bot added the size/XS label Feb 19, 2026

HTRamsey force-pushed the pr-readonly-params branch from 629c39b to f2f8050 Compare March 12, 2026 07:08

HTRamsey requested review from DonLakeFlyer and Copilot March 12, 2026 08:33

Copilot started reviewing on behalf of HTRamsey March 12, 2026 08:33 View session

Copilot AI reviewed Mar 12, 2026

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Comment thread src/FactSystem/FactMetaData.cc Outdated

Comment thread src/QmlControls/ParameterEditor.qml Outdated

Comment thread src/QmlControls/ParameterEditor.qml Outdated

DonLakeFlyer reviewed Mar 19, 2026

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DonLakeFlyer requested changes Mar 19, 2026

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julianoes mentioned this pull request Apr 1, 2026

parameter.schema.json: Add readOnly property and make type optional mavlink/mavlink#2449

Merged

julianoes force-pushed the pr-readonly-params branch from ab5c71d to 4c9826d Compare April 9, 2026 01:10

github-actions bot added the RN: MINOR FEATURE label Apr 9, 2026

julianoes and others added 6 commits April 15, 2026 09:59

Add support for read-only parameters

cdae923

This parses the readonly flag for a parameter, so that it's clear in the UI when a param can't be set.

Add lock icon and hide checkbox for read-only parameters

7ec9a18

Show a lock icon next to read-only parameter names in the parameter list and add a "Hide read-only" checkbox to filter them out entirely.

Apply suggestions from code review

4cc2ccd

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Move lock to right of param name

e81d5fa

julianoes force-pushed the pr-readonly-params branch from 4c9826d to e81d5fa Compare April 14, 2026 22:17

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julianoes commented Feb 19, 2026

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