user's preferred contrast polarity? (OS dark mode setting)

Question

Current operating systems (e.g. Windows, macOS) let the user decide if they want dark content on light blackground (classic) or rather light content on dark blackground (dark mode).

Is there something available in Java, so that my (client side) Java programs can automatically adjust their contrast polarity according to that OS user setting? I am using Swing, if that matters.

I found the system property apple.awt.application.appearance, but nothing for Windows and nothing operating system independent.

And also, is there a listener? Because that setting might change on runtime.

Motivation: inverse contrast polarity seems to inhibit myopia (Aleman et al. 2018-07-18 Science)

score 1 · Answer 1 · answered Aug 01 '21 at 16:55

There seems to be a way.

First understand that the setting of the desktop mode (light vs dark) can be read from the Windows Registry: How to detect Windows 10 light/dark mode in Win32 application?

Then it is just a question how to obtain access to this registry setting from your java application, which is described here: Read/write to Windows registry using Java

Marcus · Accepted Answer · 2021-11-24T10:34:05.070

There is a feature request (JDK-8235460) submitted in 2019.

In the meantime you might want to try jSystemThemeDetector (Apache-2 license). This library works on Windows, macOS and some Linux distributions.

OsThemeDetector.getDetector().isDark()

You can also add a listener to detect changes.

OsThemeDetector.getDetector().registerListener(isDark -> {
    SwingUtilities.invokeLater(() -> {
        if (isDark) {
            // The OS switched to a dark theme
        } else {
            // The OS switched to a light theme
        }
    });
});

Note: For JavaFX you use Platform.runLater instead of SwingUtilities.invokeLater.

user's preferred contrast polarity? (OS dark mode setting)

2 Answers2