JDK-8287261: [macos] JList Focus Ring color doesn't follow Accent color changes on macOS

[honkar-jdk]

With the proposed fix, JList's focus ring color follows accent color changes. Previously the focus ring for JList was not prominently visible and did not follow accent color changes.

While investing a similar issue related to JTable (#7768 (comment)), it was observed that List.focusCellHighlightBorder was using the cellFocusRing color as well. This PR extends the focus ring accent color changes to JLists.

Related issues: JDK-7124282 , JDK-8261243

Summary of changes

• focusCellHighlightBorder in AquaLookAndFeel changed which is used for cell border for lists and tables
• code related to on-the-fly focus ring color refactored into a separate method (changeFocusRingColor()) for re-usability
• changeFocusRingColor() called when PropertyChangeEvent == FRAME_ACTIVE_PROPERTY and the frame gains focus, instead of calling in individual swapSelectionColors in AquaFocusHandler.java
• Common test added - CellFocusRingTest, which tests for both cases - Tables & Lists.

Before and After screenshots of JList (Screenshots from SwingSet2 demo)

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Progress

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Issue

• JDK-8287261: [macos] JList Focus Ring color doesn't follow Accent color changes on macOS

Reviewers

• Tejesh R (@TejeshR13 - Author)

Reviewing

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[mlbridge]

Webrevs

• 01: Full - Incremental (e98484fe)
• 00: Full (54e54719)

[TejeshR13]

} else { Can be in same line. (Applies to other places also)

[TejeshR13]

        if (UIManager.getDefaults().get("CellFocus.color") != null
                && UIManager.getDefaults().get("CellFocus.color")
                instanceof Color)

can be changed into

        if (UIManager.getDefaults().get("CellFocus.color")
                instanceof Color)

Since if the object is null then instanceof returns false.

[honkar-jdk]

@TejeshR13 Your suggestion was to remove redundant null check. Correct, this is a better way to shorten the condition. Will have the changes done in the next commit.

[honkar-jdk]

Updated PR with changes

[mrserb]

Can you please double check how the native applications/components look when the colors are "similar".

[honkar-jdk]

Can you please double check how the native applications/components look when the colors are "similar".

@mrserb There are different variations in the native applications -

On Reminders App the background color remains the same (light gray) irrespective of changes in accent color.

On edit mode it changes to -

Under notification settings - the background color changes with accent color but it doesn't have a focus ring.

At present a focus ring is added to JLists, but since it is almost the same color as the background it is not visible. To keep it consistent with JTable changes, the ring color is made brighter and prominent. Please let me know your suggestion or thoughts on the changes.

[prsadhuk]

In "Finder" lists, it is always gray
whereas in "Desktop and screensaver", "Extensions", "Network" lists, it follows accent color
I dont see anywhere prominent focus ring is drawn encircling the list cell in native app
so probably we can just have our JList focused cell follow the accent color in JDK as well without any prominent ring..

[honkar-jdk]

In "Finder" lists, it is always gray whereas in "Desktop and screensaver", "Extensions", "Network" lists, it follows accent color I dont see anywhere prominent focus ring is drawn encircling the list cell in native app so probably we can just have our JList focused cell follow the accent color in JDK as well without any prominent ring..

Based on @prsadhuk and @mrserb suggestions and the JList LAF on native applications, the cell focus ring might not be required. At present, the JList background color changes with accent color and does not require any additional fix. Hence will be withdrawing this PR.