CATROID-1412 Fix loudness sensor being always 0

[wslany]

Summary

This PR fixes the loudness sensor returning 0 by replacing its /dev/null recorder target with a real cache-backed recording file.

https://catrobat.atlassian.net/browse/CATROID-1412

There are several red -> green commits which are only meant to make reviewing easier. The PR should be squashed when merged.

Red phase

The first commit adds a regression test for the loudness recorder setup and a small test seam in SensorLoudness so the chosen recorder path can be inspected in a unit test.

In the red state, the test fails because SensorLoudness still creates its recorder with /dev/null.

Green phase

The second commit changes the default loudness recorder target to a file inside Constants.SOUND_RECORDER_CACHE_DIRECTORY.

This keeps the test green and avoids the /dev/null setup that appears to break MediaRecorder.getMaxAmplitude() on current Android/device combinations.

Verification

• Red phase: SensorLoudnessTest fails before the fix
• Green phase: SensorLoudnessTest passes after the fix
• Manual verification on a real phone (Samsung Galaxy S24 Ultra with Android 16):
  • loudness updates correctly in the formula editor preview
  • loudness updates correctly at runtime in Catrobat programs

Your checklist for this pull request

Please review the contributing guidelines and wiki pages of this repository.

• Include the name of the Jira ticket in the PR’s title
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[wslany]

Red phase.

Add a regression test that captures the loudness recorder target path and proves that the current /dev/null setup is wrong for the loudness sensor use case.

A small test seam is introduced in SensorLoudness so the recorder path can be observed without relying on real microphone input.

[wslany]

Green phase.

Switch the loudness sensor from /dev/null to a cache-backed .m4a file in Constants.SOUND_RECORDER_CACHE_DIRECTORY.

This keeps the regression test green and restores working loudness readings on a real device.

[Copilot]

Pull request overview

Fixes the loudness sensor returning 0 by replacing the recorder output from /dev/null with a real file under the app’s cache directory, and adds a regression test to ensure the recorder path is cache-backed.

Changes:

• Add SensorLoudnessTest to assert the loudness recorder no longer targets /dev/null and uses the sound recorder cache directory.
• Update SensorLoudness to create its SoundRecorder with a cache-file output path (via a small test seam/factory).
• Centralize the default loudness recording file path (Constants.SOUND_RECORDER_CACHE_DIRECTORY/loudness_sensor.m4a).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
catroid/src/test/java/org/catrobat/catroid/formulaeditor/SensorLoudnessTest.java	Adds a Robolectric regression test verifying the recorder path selection.
catroid/src/main/java/org/catrobat/catroid/formulaeditor/SensorLoudness.java	Switches loudness recording target from /dev/null to a cache-backed file and introduces a factory seam for testing.

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[harshsomankar123-tech]

@wslany The SensorLoudness fix itself looks good to me, and the added tests are helpful.
but it also exposes an older lifecycle issue in FormulaEditorComputeDialog. The dialog sets up and starts loudness capture in setFormula(), while onStop() only unregisters the dialog itself as a SensorEventListener and never goes through the SensorHandler cleanup that stops SensorLoudness.

This likely stayed unnoticed before because SensorLoudness was using /dev/null, so on the affected devices the recorder path was effectively not working anyway. Now that this PR switches to a real cache-backed recording file, the missing teardown becomes visible: closing the compute dialog can leave the microphone recorder and loudness polling running until some later lifecycle cleanup happens.

Could You Please add explicit loudness/sensor cleanup when the dialog is dismissed or stopped, then this looks good to me.
Thanks!

[harshsomankar123-tech]

@wslany LGTM!

[wslany]

Thanks @harshsomankar123-tech , it was a good catch. I added a regression test for FormulaEditorComputeDialog.onStop() and fixed the teardown by calling SensorHandler.stopSensorListeners() there, so loudness capture is now explicitly cleaned up when the dialog closes. Red-green commits to prove it.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated no new comments.

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[wslany]

Here's a screen recording with sound of an on-device test of the build: https://photos.app.goo.gl/z1ywpYWsDRW78VLa9 --- I tested:

• working sensor in two objects in parallel
• resume from stage pause-menu
• resume when scene is continued
• restart when scene is restarted
• and that the sensor is working in the formula editor preview

[dorianpercic]

Thanks for the PR! :)
I think we should implement source code files in Kotlin, since otherwise we need a refactoring ticket again.

[wslany]

Thanks for the PR! :) I think we should implement source code files in Kotlin, since otherwise we need a refactoring ticket again.

I rewrote the touched loudness-related Java files and their dedicated tests to Kotlin in a red/green sequence:

• 2c69f34c test: rewrite loudness tests to Kotlin with red stubs
• 8f4eea0a refactor: rewrite loudness files to Kotlin

Verification:

• red: the rewritten targeted tests failed before the production rewrite
• green: the same targeted tests passed after the Kotlin production rewrite
• manual testing on a real phone:
  • loudness sensor works in the formula editor preview
  • loudness sensor works at runtime
  • compute dialog still works correctly
  • other compute-dialog sensor/reporter cases also still work, including time-based values like seconds and device sensors like inclination

[Copilot]

Pull request overview

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

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.

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[wslany]

I've also tested the latest head on my phone once more: loudness sensor works everywhere, Other sensors also work in the formula editor compute dialog.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud