iOS5及其以后提供了一个比较强大的工具UIAppearance，可以轻松的统一你的界面，它提供如下两个方法：
+ (id)appearance
+ (id)appearanceWhenContainedIn:(Class <>)ContainerClass,...
第一个方法是统一全部改，比如你设置UINavBar的tintColor，你可以这样写：[[UINavigationBar appearance] setTintColor:myColor];第二个方法是当出现在某个类的出现时候才会改变：例如：[[UIBarButtonItem appearanceWhenContainedIn:[UINavigationBar class], [UIPopoverController class], nil] setTintColor:myPopoverNavBarColor];
另外其它的UI外观修改如下：
首先定义两个值：
[csharp] view plain copy //这样方便下面多个UI界面设置，textAttributes:字体 id appearance; NSDictionary *textAttributes = nil; 1.导航条
代码如下：
[csharp] view plain copy //导航条 { appearance = [UINavigationBar appearance]; UIImage *navBackgroundImg =[UIImage imageNamed:@"background_nav"]; [appearance setBackgroundImage:navBackgroundImg forBarMetrics:UIBarMetricsDefault]; } 2.标签栏（UITabbar）
代码如下：
[csharp] view plain copy //标签栏 { appearance = [UITabBar appearance]; UIImage *tabBarBackGroungImg =[UIImage imageNamed:@"tabbar_background"]; [appearance setBackgroundImage:tabBarBackGroungImg]; UIImage * selectionIndicatorImage =[[UIImage imageNamed:@"tabbar_slider"]resizableImageWithCapInsets:UIEdgeInsetsMake(4, 0, 0, 0)] ; [appearance setSelectionIndicatorImage:selectionIndicatorImage]; } 3.分段控件（UISegmentControl）
代码如下：
[csharp] view plain copy //Segmente未选中背景 { //cap insets用来指定哪些区域是固定不变的，未制定的区域则会repeat UIImage *segmentSelected = [[UIImage imageNamed:@"bg_o.png"] resizableImageWithCapInsets:UIEdgeInsetsMake(5, 5, 5, 5)]; UIImage *segmentUnselected = [[UIImage imageNamed:@"bg.png"] resizableImageWithCapInsets:UIEdgeInsetsMake(5, 5, 5, 5)]; UIImage *segmentSelectedUnselected = [UIImage imageNamed:@"line.png"] ; UIImage *segUnselectedSelected = [UIImage imageNamed:@"line.png"] ; UIImage *segmentUnselectedUnselected = [UIImage imageNamed:@"line.png"]; appearance = [UISegmentedControl appearance]; [appearance setBackgroundImage:segmentUnselected forState:stateNormal barMetrics:UIBarMetricsDefault]; //Segmente选中背景 [appearance setBackgroundImage:segmentSelected forState:stateSelected barMetrics:UIBarMetricsDefault]; //Segmente左右都未选中时的分割线 //BarMetrics表示navigation bar的状态，UIBarMetricsDefault 表示portrait状态（44pixel height），UIBarMetricsLandscapePhone 表示landscape状态（32pixel height） [appearance setDividerImage:segmentUnselectedUnselected forLeftSegmentState:stateNormal rightSegmentState:stateNormal barMetrics:UIBarMetricsDefault]; [appearance setDividerImage:segmentSelectedUnselected forLeftSegmentState:stateSelected rightSegmentState:stateNormal barMetrics:UIBarMetricsDefault]; [appearance setDividerImage:segUnselectedSelected forLeftSegmentState:stateNormal rightSegmentState:stateSelected barMetrics:UIBarMetricsDefault]; //字体 textAttributes = [NSDictionary dictionaryWithObjectsAndKeys: BAR_BUTTON_TITLE_SHADOW_COLOR,UITextAttributeTextColor, BAR_BUTTON_TITLE_FONT,UITextAttributeFont, BAR_BUTTON_TITLE_TEXT_COLOR,UITextAttributeTextShadowColor, [NSValue valueWithCGSize:CGSizeMake(1, 1)],UITextAttributeTextShadowOffset, nil]; [appearance setTitleTextAttributes:textAttributes forState:1]; textAttributes = [NSDictionary dictionaryWithObjectsAndKeys: BAR_BUTTON_TITLE_TEXT_COLOR,UITextAttributeTextColor, BAR_BUTTON_TITLE_FONT,UITextAttributeFont, BAR_BUTTON_TITLE_SHADOW_COLOR,UITextAttributeTextShadowColor, [NSValue valueWithCGSize:CGSizeMake(1, 1)],UITextAttributeTextShadowOffset, nil]; [appearance setTitleTextAttributes:textAttributes forState:0]; } 4.UIBarbutton
注意：UIBarbutton有leftBarButton，rightBarButton和backBarButton，其中backBarButton由于带有箭头，需要单独设置。
barButton背景设置是ios6.0及以后的，而backbutton是ios5.0及以后的，这里要注意！
代码如下：
[csharp] view plain copy //UIBarButtonItem { //只是修改导航条上的UIBarButtonItem appearance = [UIBarButtonItem appearanceWhenContainedIn:[UINavigationBar class], nil]; //backBarButton和leftBarButton，rightBarButton的字体同时设置 textAttributes = [NSDictionary dictionaryWithObjectsAndKeys: BAR_BUTTON_TITLE_TEXT_COLOR,UITextAttributeTextColor, BAR_BUTTON_TITLE_FONT,UITextAttributeFont, BAR_BUTTON_TITLE_SHADOW_COLOR,UITextAttributeTextShadowColor, [NSValue valueWithCGSize:CGSizeMake(1, 1)],UITextAttributeTextShadowOffset, nil]; [appearance setTitleTextAttributes:textAttributes forState:0]; textAttributes = [NSDictionary dictionaryWithObjectsAndKeys: BAR_BUTTON_TITLE_SHADOW_COLOR,UITextAttributeTextColor, BAR_BUTTON_TITLE_FONT,UITextAttributeFont, BAR_BUTTON_TITLE_TEXT_COLOR,UITextAttributeTextShadowColor, [NSValue valueWithCGSize:CGSizeMake(1, 1)],UITextAttributeTextShadowOffset, nil]; [appearance setTitleTextAttributes:textAttributes forState:1]; UIImage *leftButton = [[UIImage imageNamed:@"bgLeftButton.png"] stretchableImageWithLeftCapWidth:14 topCapHeight:0]; UIImage *normalButton = [[UIImage imageNamed:@"bgNormalButton.png"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 5, 0, 5)]; //leftBarButton，rightBarButton背景 [appearance setBackgroundImage:normalButton forState:UIControlStateNormal style:UIBarButtonItemStyleBordered barMetrics:UIBarMetricsDefault]; [appearance setBackgroundImage:normalButton forState:UIControlStateHighlighted style:UIBarButtonItemStyleBordered barMetrics:UIBarMetricsDefault]; //单独设置backBarButton背景 [appearance setBackButtonBackgroundImage:leftButton forState:0 barMetrics:UIBarMetricsDefault]; [appearance setBackButtonBackgroundImage:leftButton forState:1 barMetrics:UIBarMetricsDefault]; [appearance setBackButtonTitlePositionAdjustment:UIOffsetMake(2, -1) forBarMetrics:UIBarMetricsDefault]; } 5.工具栏（UIToolbar）
代码如下：
[csharp] view plain copy //toolBar { appearance = [UIToolbar appearance]; //样式和背景二选一即可，看需求了 //样式（黑色半透明，不透明等）设置 [appearance setBarStyle:UIBarStyleBlackTranslucent]; //背景设置 [appearance setBackgroundImage:[UIImage imageNamed:@"background_nav.png"] forToolbarPosition:UIToolbarPositionAny barMetrics:UIBarMetricsDefault]; } 相关资源：python入门教程(PDF版)
