iPad用户体验守则

1iPad用户体验守则ContentandinteractivityareparamountintheiPaduserexperience.ThebestiPadapplicationselevatecontentandinteractivitybydoingthreethingsreallywell:iPad用户体验最主要体现在内容和交互：TheydownplayapplicationUIsothatthefocusisonthecontentthatpeoplewant.淡化程序UI，以便用户关注所需的内容。Theypresentthecontentinbeautiful,oftenrealisticways.美观的内容形式，富有真实感。Theytakefulladvantageofdevicecapabilitiestoenableenhancedinteractionwiththecontent.充分利用设备的性能来增强内容的交互性。Theprimacyofcontentandinteractivityinformtheguidelinesinthischapter.KeepthisinmindasyoudesignyouriPadapplication.在开发你自己的iPad应用时，请谨记这篇守则中提到的关于内容和交互性的一切。AimtoSupportAllOrientations支持所有方位BeingabletoruninallorientationsisanimportantfactorinthesuccessofyouriPadapplication.Thelargescreenmitigatespeople’sdesiretorotatethedevicetolandscapeto“seemore.”And,becausepeopledon’tpaymuchattentiontotheminimaldeviceframeorthelocationoftheHomebutton,theydon’tviewthedeviceashavingadefaultorientation.Thisleadspeopletoexpectapplicationstorunwellinthedeviceorientationthey’recurrentlyusing.Asmuchaspossible,yourapplicationshouldencouragepeopletointeractwithiPadfromanysidebyprovidingagreatexperienceinallorientations.ThedifferencebetweenlandscapeandportraitdimensionscansignificantlyaffecthowyourUIfitsonscreen.Preciselyhowyourespondtorotationmightvary,butyoushouldmakeeveryefforttoabidebythefollowingguidelines.优秀iPad程序的其中一个重要因素是可以在所有方位上运行。竖向的大屏幕可以满足用户浏览内容的需求（当竖屏幕较小时，用户就会将屏幕旋转为横屏幕，这样一行就可以显示较多的文字）。用户不太会注意最小设备结构（minimaldeviceframe；使用iPhone时，用户单手握住手机时，屏幕多为竖向显示；而双手使用iPad，屏幕的显示方位并不能确定）或者home按键的位置，他们不认为设备有默认方位。这就导致用户期望程序可以在当前方位上运行。所以程序尽量满足iPad各方位的运行要求。Maintainfocusontheprimarycontent.Thisisyourhighestpriority.Peopleuseyourapplicationtoviewandinteractwiththecontenttheycareabout.Alteringthefocusonthat2contentindifferentorientationscanmakepeoplefeelthatthey’velostcontrolovertheapplication.保证以首要内容为重点。当旋转iPad的方位时，如重点显示的内容发生变化，用户会感觉对程序失去控制。Considerchanginghowyoudisplayauxiliaryinformationorfunctionality.Althoughyoushouldmakesurethatthemostimportantcontentisalwaysinfocus,youcanrespondtorotationbychanginghowyouprovidesecondarycontent.旋转时如何显示辅助信息或者功能。尽管能保证上一条，还要考虑如何显示较为次要的信息。InMail,forexample,thelistsofaccountsandmailboxescomprisesecondarycontent(themaincontentistheselectedmessage).Inlandscape,secondarycontentisdisplayedintheleftpaneofasplitview;inportrait,it’sdisplayedinapopover.例如邮箱功能中，首要内容时发邮件，次要内容是联系人和收件箱的列表。横屏的次要内容显示在左边的分视图中3竖屏的次要内容显示在气泡框中。Or,consideragamethatdisplaysarectangulargameboardinlandscape.Inportrait,thegameneedstoredrawtheboardtofitwellonthescreen,whichmightresultinadditionalspaceaboveorbelowtheboard.Insteadofverticallystretchingthegameboardtofitthespaceorleavingthespaceempty,thegamecoulddisplaysupplementalinformationorobjectsintheadditionalspace.Bothoftheseexamplesmaintaintheuser’sfocusontheprimarycontentandtakebestadvantageofthecurrentscreendimensionswithoutalteringtheprimaryfunctionalityoftheapplication.再如，横屏时，一款游戏以长方形显示，当旋转到竖屏时，需要调整屏幕上的显示区域，游戏显示边框的上面或者下面增加显示空间，用于显示辅助信息，而不是垂直拉伸显示区域来撑满整个屏幕。4Avoidradicalorgratuitouschangesinlayout.ThelargeiPadscreenallowsyoutoprovideasimilarUIlayoutinallorientations.Forexample,ifyoudisplayimagesinagridwhileinlandscape,youdon’tneedtodisplaythesameinformationinalistwhileinportrait(althoughyoumightadjustthedimensionsofthegrid).Focusonprovidingaconsistentexperienceinallorientations,evenifthelayoutofsecondaryinformationmightchange.Acomparableexperienceinallorientationsallowspeopletomaintaintheirusagepatternswhentheyrotatethedevice.Whenpossible,avoidreformattinginformationandrewrappingtextonrotation.Strivetomaintainasimilarformatinallorientations.Especiallyifpeoplearereadingtext,it’simportanttoavoidcausingthemtolosetheirplacewhentheyrotatethedevice.避免布局变化过大或者无缘由地改变。所有方位中都显示相似的UI布局旋转时尽可能保留信息和文本的原有格式。尤其阅读文本时，重要的是避免旋转之后用户找不到读到哪儿了。如果非要对页面重新布局，可以使用动画帮助用户理解当前页面的变化。例如，当旋转时要必须增加或者移除文本框时，可以选择隐藏动作并在新布局中简单地淡出。为了有助于合理地设计旋转动作，可考虑在真实的生活中是如何和它们交互的。AvoidprovidingaUIelementordefiningarotationgesturethatrotatesyourcontent.Instead,peopleshouldbeabletorotateyourcontentbyrotatingthedevice.避免使用UI元素或者定义一个旋转的手势来完成旋转动作。应该是内容随着iPad的旋转而旋转。Provideauniquelaunchimageforeachorientation.Wheneachorientationhasauniquelaunchimage,peopleexperienceasmoothapplicationstartregardlessofthecurrentdeviceorientation.IncontrastwiththeHomescreenoniPhone,theiPadHomescreensupportsallorientations,sopeoplearelikelytostartyourapplicationinthesameorientationinwhichtheyquitthepreviousapplication.See“CreateaLaunchImageforEachOrientation”formoreinformationoniPadlaunchimages.为每个显示方位各提供一个启动图片。比如提供1004×768和748×1024的图片来满足两个方位的显示要求。Thinktwicebeforepreventingyourapplicationfromrunninginallorientations.Peopleexpecttouseyourapplicationinwhicheverorientationthey’recurrentlyholdingtheiriPad,andit’sbestwhenyoucanfulfillthatexpectation.Incertaincases,however,anapplicationneedstoruninportraitonlyorinlandscapeonly.Ifit’sessentialthatyourapplicationruninonlyoneorientation,youshould:仔细考虑程序是否可以在所有方位上运行。有些程序只能在横屏或者竖屏下显示，此时：Launchinyoursupportedorientation,regardlessofthecurrentdeviceorientation.Forexample,ifyourgameormedia-viewingapplicationrunsinlandsc