iOS5及其以后提供了一個(gè)比較強(qiáng)大的工具UIAppearance，我們通過UIAppearance設(shè)置一些UI的全局效果，這樣就可以很方便的實(shí)現(xiàn)UI的自定義效果又能最簡單的實(shí)現(xiàn)統(tǒng)一界面風(fēng)格，它提供如下兩個(gè)方法。

+ (id)appearance

這個(gè)方法是統(tǒng)一全部改，比如你設(shè)置UINavBar的tintColor，你可以這樣寫：[[UINavigationBar appearance] setTintColor:myColor];

+ (id)appearanceWhenContainedIn:(Class <>)ContainerClass,...

這個(gè)方法可設(shè)置某個(gè)類的改變：例如：設(shè)置UIBarButtonItem 在UINavigationBar、UIPopoverController、UITabbar中的效果。就可以這樣寫

[[UIBarButtonItem appearanceWhenContainedIn:[UINavigationBar class], [UIPopoverController class],[UITabbar class] nil] setTintColor:myPopoverNavBarColor];

請(qǐng)注意＊使用appearance設(shè)置UI效果最好采用全局的設(shè)置，在所有界面初始化前開始設(shè)置，否則可能失效。

支持UIAppearance協(xié)議的類可以訪問appearance selector ,它為receiver返回appearance proxy，我么可以給proxy發(fā)一些消息，諸如setTintColor:等

但是它并不是支持所有的UI類。下面列出它支持的類

1.UIActivitiIndicatorView

2.UIBarButtonItem

3.UIBarItem

4.UINavgationBar

5.UIPopoverControll

6.UIProgressView

7.UISearchBar

8.UISegmentControll

9.UISlider

10.UISwitch

11.UITabBar

12.UITabBarItem

13.UIToolBar

14.UIView

15.UIViewController

具體UI外觀修改如下：

1.修改導(dǎo)航欄背景

代碼如下:

UINavigationBar * appearance = [UINavigationBar appearance];

UIImage *navBackgroundImg =[UIImage imageNamed:@"navBg.png”];

[appearance setBackgroundImage:navBackgroundImgforBarMetrics:UIBarMetricsDefault];

2.標(biāo)簽欄（UITabbar）

代碼如下:

UITabBar *appearance = [UITabBar appearance];

//設(shè)置背景圖片

[appearance setBackgroundImage:[UIImage imageNamed:@"tabbar_bg.png"]];

//門置選擇item的背景圖片

UIImage * selectionIndicatorImage =[[UIImageimageNamed:@"tabbar_slider"]resizableImageWithCapInsets:UIEdgeInsetsMake(4, 0, 0,0)] ;

[appearance setSelectionIndicatorImage:selectionIndicatorImage];

3.分段控件（UISegmentControl）

代碼如下:

UISegmentedControl *appearance = [UISegmentedControl appearance];

//Segmenteg正常背景

[appearance setBackgroundImage:[UIImage imageNamed:@"Segmente.png"]

forState:UIControlStateNormal

barMetrics:UIBarMetricsDefault];

//Segmente選中背景

[appearance setBackgroundImage:[UIImage imageNamed:@"Segmente_a.png"]

forState:UIControlStateSelected

barMetrics:UIBarMetricsDefault];

//Segmente左右都未選中時(shí)的分割線

//BarMetrics表示navigation bar的狀態(tài)，UIBarMetricsDefault 表示portrait狀態(tài)（44pixel height），UIBarMetricsLandscapePhone 表示landscape狀態(tài)（32pixel height）

[appearance setDividerImage:[UIImage imageNamed:@"Segmente_line.png"]

forLeftSegmentState:UIControlStateNormal

rightSegmentState:UIControlStateNormal

barMetrics:UIBarMetricsDefault];

[appearance setDividerImage:[UIImage imageNamed:@"Segmente_line.png"]

forLeftSegmentState:UIControlStateSelected

rightSegmentState:UIControlStateNormal

barMetrics:UIBarMetricsDefault];

[appearance setDividerImage:[UIImage imageNamed:@"Segmente_line.png"]

forLeftSegmentState:UIControlStateNormal

rightSegmentState:UIControlStateSelected

barMetrics:UIBarMetricsDefault];

//字體

NSDictionary *textAttributes1 = @{UITextAttributeFont: [UIFont systemFontOfSize:18],

UITextAttributeTextColor: [UIColor blueColor],

UITextAttributeTextShadowColor: [UIColor whiteColor],

UITextAttributeTextShadowOffset: [NSValuevalueWithCGSize:CGSizeMake(1, 1)]};

[appearance setTitleTextAttributes:textAttributes1 forState:1];

NSDictionary *textAttributes2 = @{UITextAttributeFont: [UIFont systemFontOfSize:18],

UITextAttributeTextColor: [UIColor whiteColor],

UITextAttributeTextShadowColor: [UIColor blackColor],

UITextAttributeTextShadowOffset: [NSValuevalueWithCGSize:CGSizeMake(1, 1)]};

[appearance setTitleTextAttributes:textAttributes2 forState:0];

4.UIBarbutton

注意：UIBarbutton有l(wèi)eftBarButton，rightBarButton和backBarButton，其中backBarButton由于帶有箭頭，需要單獨(dú)設(shè)置。

barButton背景設(shè)置是ios6.0及以后的，而backbutton是ios5.0及以后的，這里要注意！

代碼如下:

//修改導(dǎo)航條上的UIBarButtonItem

UIBarButtonItem *appearance = [UIBarButtonItem appearanceWhenContainedIn:[UINavigationBar class], nil];

//設(shè)置導(dǎo)航欄的字體包括backBarButton和leftBarButton，rightBarButton的字體

NSDictionary *textAttributes = @{UITextAttributeFont: [UIFontsystemFontOfSize:18],

UITextAttributeTextColor: [UIColorblueColor],

UITextAttributeTextShadowColor: [UIColorwhiteColor],

UITextAttributeTextShadowOffset: [NSValuevalueWithCGSize:CGSizeMake(1, 1)]};

[appearance setTitleTextAttributes:textAttributes forState:1];//forState為0時(shí)為下正常狀態(tài)，為1時(shí)為點(diǎn)擊狀態(tài)。

//修改leftBarButton，rightBarButton背景效果

[appearance setBackgroundImage:[UIImage imageNamed:@"navBarButton.png"]

forState:UIControlStateNormal

style:UIBarButtonItemStyleBordered

barMetrics:UIBarMetricsDefault];

[appearance setBackgroundImage:[UIImage imageNamed:@"navBarButton_a.png"]

forState:UIControlStateHighlighted

style:UIBarButtonItemStyleBordered

barMetrics:UIBarMetricsDefault];

//backBarButton需要單獨(dú)設(shè)置背景效果。只能在ios6.0以后才能用

[appearance setBackButtonBackgroundImage:[UIImage imageNamed:@"nav_bg.png"]

forState:0

barMetrics:UIBarMetricsDefault];

[appearance setBackButtonBackgroundImage:[UIImage imageNamed:@"work.png"]

forState:1

barMetrics:UIBarMetricsDefault];

[appearance setBackButtonTitlePositionAdjustment:UIOffsetMake(2, -1)

forBarMetrics:UIBarMetricsDefault];

5.工具欄（UIToolbar）

UIToolbar *appearance = [UIToolbar appearance];

//樣式和背景二選一即可，看需求了

//樣式（黑色半透明，不透明等）設(shè)置

[appearance setBarStyle:UIBarStyleBlackTranslucent];

//背景設(shè)置

[appearance setBackgroundImage:[UIImage imageNamed:@"toolbarBg.png"]

forToolbarPosition:UIToolbarPositionAny

barMetrics:UIBarMetricsDefault];

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