设置通用的NavagationController

/** * 当第一次使用这个类的时候会调用一次 */+ (void)initialize{    // 当导航栏用在XMGNavigationController中, appearance设置才会生效//    UINavigationBar *bar = [UINavigationBar appearanceWhenContainedIn:[self class], nil];//设置通用的bar    UINavigationBar *bar = [UINavigationBar appearance];    [bar setBackgroundImage:[UIImage imageNamed:@"navigationbarBackgroundWhite"] forBarMetrics:UIBarMetricsDefault];//设置bar中字体的大小    [bar setTitleTextAttributes:@{NSFontAttributeName : [UIFont boldSystemFontOfSize:20]}];        // 设置item    UIBarButtonItem *item = [UIBarButtonItem appearance];    // UIControlStateNormal    NSMutableDictionary *itemAttrs = [NSMutableDictionary dictionary];    itemAttrs[NSForegroundColorAttributeName] = [UIColor blackColor];    itemAttrs[NSFontAttributeName] = [UIFont systemFontOfSize:17];    [item setTitleTextAttributes:itemAttrs forState:UIControlStateNormal];    // UIControlStateDisabled    NSMutableDictionary *itemDisabledAttrs = [NSMutableDictionary dictionary];    itemDisabledAttrs[NSForegroundColorAttributeName] = [UIColor lightGrayColor];    [item setTitleTextAttributes:itemDisabledAttrs forState:UIControlStateDisabled];}复制代码