iOS 5 以后 UINavigationController 可以 改变UINavigationBar导航条标题颜色和字体
[self.navigationController.navigationBar setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
[UIColor colorWithRed:0 green:0.7 blue:0.8 alpha:1], UITextAttributeTextColor,
[UIColor colorWithRed:0 green:0.7 blue:0.8 alpha:1], UITextAttributeTextShadowColor,
[NSValue valueWithUIOffset:UIOffsetMake(0, 0)], UITextAttributeTextShadowOffset,
[UIFont fontWithName:@"Arial-Bold" size:0.0], UITextAttributeFont,
nil]];
其中 UITextAttributeTextColor和UITextAttributeFont 属性是文字颜色和字体