How to detect Xamarin Forms System Theme Change

Question

How to detect Xamarin Forms System Theme Change from Light to Dark ??

I have detected the App Theme change but how can I detect the change of whole operating/device theme change ?

I am using :

Application.Current.RequestedThemeChanged

Answer 1

As mentionned in the docs react to theme changes you can achieve it by handeling the event Application.RequestedThemeChanged

Application.Current.RequestedThemeChanged += (s, a) => { 
    switch(a.RequestedTheme) {
        case OSAppTheme.Dark:
            //do something
            break;
        case OSAppTheme.Light:
            //do something
            break;
        case OSAppTheme.Unspecified:
            //do something
            break;
    }
};

Additional flag in order to work for Android

[Activity(..., ConfigurationChanges = ConfigChanges.UiMode...

To respond to theme changes on Android you must include the ConfigChanges.UiMode flag in the Activity attribute of your MainActivity class.