iOS 15导航栏透明变白问题

if( @available(iOS 15.0, *)) {

        NSMutableDictionary *attrs = [NSMutableDictionary dictionary];

        attrs[NSFontAttributeName] = [UIFont systemFontOfSize:17];

        attrs[NSForegroundColorAttributeName] = [UIColor whiteColor];

        UINavigationBarAppearance *appearance = [UINavigationBarAppearance new];

        [appearance configureWithOpaqueBackground];

        appearance.backgroundColor = MAINCOLOR;

        appearance.titleTextAttributes = attrs;

        [[UINavigationBar appearance] setStandardAppearance:appearance];

        [[UINavigationBar appearance] setScrollEdgeAppearance:appearance];

    }

AppDelegate didFinishLaunchingWithOptions中加入