ios5及其以后提供了一個(gè)比較強(qiáng)大的工具uiappearance，我們通過(guò)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(jiǎn)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(xiě)：[[uinavigationbar appearance] settintcolor:mycolor];
+ (id)appearancewhencontainedin:(class <>)containerclass,...
這個(gè)方法可設(shè)置某個(gè)類(lèi)的改變：例如：設(shè)置uibarbuttonitem 在uinavigationbar、uipopovercontroller、uitabbar中的效果。就可以這樣寫(xiě)
[[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(kāi)始設(shè)置，否則可能失效。
支持uiappearance協(xié)議的類(lèi)可以訪問(wèn)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(lèi)。下面列出它支持的類(lèi)
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(mén)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];