在iOS开发中定制导航栏是常见的需求。但是时间久了，有些属性不知不觉就忘了，要用时一下子记不住了，因此给自己记录一下。
#define UIColorFromRGB(rgbValue) [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 green:((float)((rgbValue & 0xFF00) >> 8))/255.0 blue:((float)(rgbValue & 0xFF))/255.0 alpha:1.0]
//导航栏颜色
[[UINavigationBar appearance] setBarTintColor:UIColorFromRGB(0x16a11e)];
//返回按钮颜色
[[UINavigationBar appearance] setTintColor:[UIColor whiteColor]];
//标题颜色
[[UINavigationBar appearance] setTitleTextAttributes:@{NSForegroundColorAttributeName:[UIColor whiteColor]}];
//自定义返回按钮
UIImage *backButtonImage = [[UIImage imageNamed:@"icon_back"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 35, 0, 0)];
[[UIBarButtonItem appearance] setBackButtonBackgroundImage:backButtonImage forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(NSIntegerMin, NSIntegerMin) forBarMetrics:UIBarMetricsDefault];
