Adding Dark Mode Feature

[rickieleehao]

Dark Mode Feature allow the application to have a darker UI.

• added a button with action listener
• added a changeBGColor method

[pH-7]

Great idea @rickieleehao! However, adding again another button for the dark mode doesn't really make sense here since it goes beyond the scope of the calculator. It would be nice then to enable the dark mode (like implemented) only if the OS has the dark mode enabled.

MAYBE... we could use something like https://github.com/Dansoftowner/jSystemThemeDetector ...

final OsThemeDetector detector = OsThemeDetector.getDetector();
final boolean isDarkThemeUsed = detector.isDark();
if (isDarkThemeUsed) {
    //The OS uses a dark theme
} else {
    //The OS uses a light theme
}

[rickieleehao]

Thank you for your feedback! This is actually one of my current university assignment which we have to learn the workflow of how people contribute in open-source environment and attempt to make some contribution. Nevertheless, I appreciate to receive your reply and sorry for any inconveniences.

[pH-7]

No worries @rickieleehao, that's all good 🙂 Are you still willing to complete your changes and get your PR merged with the given suggestion? If not, I will close it.