iOS

+ (void)applyTheme:(NSString * __nullable)themeID {
    // Obtain the ID of the last theme used by the app
    NSString *lastThemeID = [self getCacheThemeID];
    if (themeID.length) {
        lastThemeID = themeID;
    }

    // Components: apply/uninstall themes
    if (lastThemeID == nil || lastThemeID.length == 0 || [lastThemeID isEqualToString:@"system"]) {
        // If the theme ID is empty or the Auto mode is used, uninstall the themes that are currently used by all components.
        [TUIShareThemeManager unApplyThemeForModule:TUIThemeModuleAll];
    } else {
          // Apply the last theme for all components
        [TUIShareThemeManager applyTheme:lastThemeID forModule:TUIThemeModuleAll];
    }

    // Dark style of the system: mutually exclusive with a theme
    dispatch_async(dispatch_get_main_queue(), ^{
        if (@available(iOS 13.0, *)) {
            if (lastThemeID == nil || lastThemeID.length == 0 || [lastThemeID isEqualToString:@"system"]) {
                // Automatically switching to match system settings
                UIApplication.sharedApplication.keyWindow.overrideUserInterfaceStyle = 0;
            } else if ([lastThemeID isEqual:@"dark"]) {
                // Forcibly switch to the Dark mode
                UIApplication.sharedApplication.keyWindow.overrideUserInterfaceStyle = UIUserInterfaceStyleDark;
            } else {
                // Ignore the system change, forcibly switch to the Light mode and use the Light theme
                UIApplication.sharedApplication.keyWindow.overrideUserInterfaceStyle = UIUserInterfaceStyleLight;
            }
        }
    });
}