MFMessageComposeViewController修改导航栏以及Cancel按钮的颜色

[[UIBarButtonItem appearanceWhenContainedIn:[UINavigationBar class], nil] setTintColor:[UIColor whiteColor]];

NSDictionary *dic = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:[UIColor colorWithRed:200 green:200 blue:200 alpha:1], [UIFont boldSystemFontOfSize:18.0f], [UIColor colorWithWhite:0.0 alpha:1], nil] forKeys:[NSArray arrayWithObjects:UITextAttributeTextColor, UITextAttributeFont, UITextAttributeTextShadowColor, nil]];

[[UINavigationBar appearance] setTitleTextAttributes:dic];