iOS 修改导航栏文字

自定义导航栏文字：

UILabel *title = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 100, 44)];

title.text = @"title3";

title.textAlignment = NSTextAlignmentCenter;

title.textColor = [UIColor redColor];

self.navigationItem.titleView = title;