Fix bars turning green issue when switching from a graph with empty data

[aditi-bhatia]

Fixes #20413

This PR fixes an issue where bars for all graphs would turn a gradient green after navigating to a graph with empty data. Only categories with no data should display the gradient green bars and all other categories with data should have blue bars.

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To Test:

1. While on the Stats Traffic tab, click a category with empty data. You can use the mobile.blog site for testing which currently has 0 comments in the month view.
2. You should see a green gradient bar for any category with empty data.
3. Navigate to views or any other category with data. The bars should change to blue and not remain gradient green.

Video of bug occurring after clicking likes or comments (empty data) and then navigating back to views or visitors:

Screen_Recording_20240305_141423_Jetpack.Beta.mp4

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Regression Notes

1. Potential unintended areas of impact

   • TODO

2. What I did to test those areas of impact (or what existing automated tests I relied on)

   • TODO

3. What automated tests I added (or what prevented me from doing so)

   • TODO

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PR Submission Checklist:

• I have completed the Regression Notes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

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Testing Checklist (strike-out the not-applying and unnecessary ones):

• WordPress.com sites and self-hosted Jetpack sites.
• Portrait and landscape orientations.
• Light and dark modes.
• Fonts: Larger, smaller and bold text.
• High contrast.
• Talkback.
• Languages with large words or with letters/accents not frequently used in English.
• Right-to-left languages. (Even if translation isn’t complete, formatting should still respect the right-to-left layout)
• Large and small screen sizes. (Tablet and smaller phones)
• Multi-tasking: Split screen and Pop-up view. (Android 10 or higher)

[wpmobilebot]

📲 You can test the changes from this Pull Request in WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr20436-02daa2b
	Commit	02daa2b
	Direct Download	wordpress-prototype-build-pr20436-02daa2b.apk

Note: Google Login is not supported on these builds.

[wpmobilebot]

📲 You can test the changes from this Pull Request in Jetpack by scanning the QR code below to install the corresponding build.

	App Name	Jetpack
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr20436-02daa2b
	Commit	02daa2b
	Direct Download	jetpack-prototype-build-pr20436-02daa2b.apk

Note: Google Login is not supported on these builds.

[irfano]

This appears to be a bug from the chart library. Although we're updating dataSet of the BarChart, BarCharts BarChartRenderer is still using gradient colors from the previous chart.
I see a minor side effect of setting gradient colors again here. It causes the chart to render gradient color as a single color, an unnecessary process from the performance perspective.
May I suggest a simpler alternative solution? By setting the shader to null, we can prevent BarChartRenderers from drawing gradient. Wdyt?

Suggested change

	dataSet.color = ContextCompat.getColor(context, R.color.blue_50)
	dataSet.setGradientColor(
	ContextCompat.getColor(
	context,
	R.color.blue_50
	), ContextCompat.getColor(
	context,
	R.color.blue_50
	)
	)
	chart.renderer.paintRender.shader = null
	dataSet.color = ContextCompat.getColor(context, R.color.blue_50)

[aditi-bhatia]

Hi @irfano thanks for the suggestion! Yes, I agree that it's an issue with the library itself. I was concerned about the unnecessary process as well but noticed that BarChartViewHolder uses a similar workaround (lines 233-241 and 256-264):

            ContextCompat.getColor(
                context,
                R.color.stats_bar_chart_top
            ), ContextCompat.getColor(
                context,
                R.color.stats_bar_chart_top
            )
        )

I can go ahead and update the usage in TrafficBarChartViewHolder, but do you think it's a good idea to update these other occurrences as well?

[irfano]

Yes, I think we can update it on both places. I tested my suggestion and didn't notice any issues.

[aditi-bhatia]

Hi @irfano, I pushed the changes we discussed above so it's ready if you'd like to take another look. Thanks!

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[irfano]

LGTM! 👍🏻