外文资料翻译格式.docx

外文资料翻译格式.docx

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外文资料翻译格式

外文资料翻译

资料来源：

文章名：

WhatisAndroid?

书刊名：

《AndroidWirelessApplicationDevelopment》

作者：

ShaneConder

出版社：

Addison-Wesley，2010

章节：

1.2AboutAndroid

页码：

P2~P4

文章译名：

andriod是什么？

姓名：

学号：

指导教师（职称）：

专业：

班级：

所在学院：

WhatIsAndroid?

KeySkills&Concepts

●Historyofembeddeddeviceprogramming

●ExplanationofOpenHandsetAlliance

●FirstlookattheAndroidhomescreen

Itcanbesaidthat,forawhile,traditionaldesktopapplicationdevelopershavebeenspoiled.Thisisnottosaythattraditionaldesktopapplicationdevelopmentiseasierthanotherformsofdevelopment.However,astraditionaldesktopapplicationdevelopers,wehavehadtheabilitytocreatealmostanykindofapplicationwecanimagine.IamincludingmyselfinthisgroupingbecauseIgotmystartindesktopprogramming.

Oneaspectthathasmadedesktopprogrammingmoreaccessibleisthatwehavehadtheabilitytointeractwiththedesktopoperatingsystem,andthusinteractwithanyunderlyinghardware,prettyfreely（oratleastwithminimalexceptions）.Thiskindoffreedomtoprogramindependently,however,hasneverreallybeenavailabletothesmallgroupofprogrammerswhodaredtoventureintothemurkywatersofcellphonedevelopment.

NOTE

Irefertotwodifferentkindsofdevelopersinthisdiscussion:

traditionaldesktopapplicationdevelopers,whoworkinalmostanylanguageandwhoseendproduct,applications,arebuilttorunonany“desktop”operatingsystem;andAndroiddevelopers,JavadeveloperswhodevelopfortheAndroidplatform.Thisisnotforthepurposesofsayingoneisbyanymeansbetterorworsethantheother.

Rather,thedistinctionismadeforpurposesofcomparingthedevelopmentstylesandtoolsofdesktopoperatingsystemenvironmentstothemobileoperatingsystemenvironment,Android.

BriefHistoryofEmbeddedDeviceProgramming

Foralongtime,cellphonedeveloperscomprisedasmallsectofaslightlylargergroupofdevelopersknownasembeddeddevicedevelopers.Seenasaless“glamorous”siblingtodesktop—andlaterweb—development,embeddeddevicedevelopmenttypicallygottheproverbialshortendofthestickasfarashardwareandoperatingsystemfeatures,becauseembeddeddevicemanufacturerswerenotoriouslystingyonfeaturesupport.Embeddeddevicemanufacturerstypicallyneededtoguardtheirhardwaresecretsclosely,sotheygaveembeddeddevicedevelopersfewlibrariestocallwhentryingtointeractwithaspecificdevice.

Embeddeddevicesdifferfromdesktopsinthatanembeddeddeviceistypicallya“computeronachip.”Forexample,consideryourstandardtelevisionremotecontrol;itisnotreallyseenasanoverwhelmingachievementoftechnologicalcomplexity.Whenanybuttonispressed,achipinterpretsthesignalinawaythathasbeenprogrammedintothedevice.Thisallowsthedevicetoknowwhattoexpectfromtheinputdevice（keypad）,andhowtorespondtothosecommands（forexample,turnonthetelevision）.Thisisasimpleformofembeddeddeviceprogramming.However,believeitornot,simpledevicessuchasthesearedefinitelyrelatedtotherootsofearlycellphonedevicesanddevelopment.

Mostembeddeddevicesran（andinsomecasesstillrun）proprietaryoperatingsystems.Thereasonforchoosingtocreateaproprietaryoperatingsystemratherthanuseanyconsumersystemwasreallyaproductofnecessity.Simpledevicesdidnotneedveryrobustandoptimizedoperatingsystems.

Asaproductofdeviceevolution,manyofthemorecomplexembeddeddevices,suchasearlyPDAs,householdsecuritysystems,andGPSs,movedtosomewhatstandardizedoperatingsystemplatformsaboutfiveyearsago.Small-footprintoperatingsystemssuchasLinux,orevenanembeddedversionofMicrosoftWindows,havebecomemoreprevalentonmanyembeddeddevices.Aroundthistimeindeviceevolution,cellphonesbranchedfromotherembeddeddevicesontotheirownpath.Thisbranchingisevidentwhenyouexaminetheirarchitecture.

Nearlysincetheirinception,cellphoneshavebeenfringedevicesinsofarastheyrunonproprietarysoftware—softwarethatisownedandcontrolledbythemanufacturer,andisalmostalwaysconsideredtobea“closed”system.Thepracticeofmanufacturersusingproprietaryoperatingsystemsbeganmoreoutofnecessitythananyotherreason.Thatis,cellphonemanufacturerstypicallyusedhardwarethatwascompletelydevelopedin-house,oratleasthardwarethatwasspecificallydevelopedforthepurposesofrunningcellphoneequipment.Asaresult,therewerenoopenlyavailable,off-the-shelfsoftwarepackagesorsolutionsthatwouldreliablyinteractwiththeirhardware.Sincethemanufacturersalsowantedtoguardverycloselytheirhardwaretradesecrets,someofwhichcouldberevealedbyallowingaccesstothesoftwarelevelofthedevice,thecommonpracticewas,andinmostcasesstillis,tousecompletelyproprietaryandclosedsoftwaretoruntheirdevices.Thedownsidetothisisthatanyonewhowantedtodevelopapplicationsforcellphonesneededtohaveintimateknowledgeoftheproprietaryenvironmentwithinwhichitwastorun.Thesolutionwastopurchaseexpensivedevelopmenttoolsdirectlyfromthemanufacturer.Thisisolatedmanyofthe“homebrew”developers.

NOTE

Agrowingcultureofhomebrewdevelopershasembracedcellphoneapplicationdevelopment.Theterm“homebrew”referstothefactthatthesedeveloperstypicallydonotworkforacellphonedevelopmentcompanyandgenerallyproducesmall,one-offproductsontheirowntime.

Another,morecompelling“necessity”thatkeptcellphonedevelopmentoutofthehandsoftheeverydaydeveloperwasthehardwaremanufacturers’solutiontothe“memoryversusneed”dilemma.Untilrecently,cellphonesdidlittlemorethanexecuteandreceivephonecalls,trackyourcontacts,andpossiblysendandreceiveshorttextmessages;notreallythe“Swissarmyknives”oftechnologytheyaretoday.Evenaslateas2002,cellphoneswithcameraswerenotcommonlyfoundinthehandsofconsumers.

By1997,smallapplicationssuchascalculatorsandgames（Tetris,forexample）crepttheirwayontocellphones,buttheoverwhelmingfunctionwasstillthatofaphonedialeritself.Cellphoneshadnotyetbecomethemultiuse,multifunctionpersonaltoolstheyaretoday.NooneyetsawtheneedforInternetbrowsing,MP3playing,oranyofthemultitudesoffunctionsweareaccustomedtousingtoday.Itispossiblethatthecellphonemanufacturersof1997didnotfullyperceivetheneedconsumerswouldhaveforanall-in-onedevice.However,eveniftheneedwaspresent,alackofdevicememoryandstoragecapacitywasanevenbiggerobstacletoovercome.Morepeoplemayhavewantedtheirdevicestobeall-in-onetools,butmanufacturersstillhadtoclimbthememoryhurdle.

Toputtheproblemsimply,ittakesmemorytostoreandrunapplicationsonanydevice,cellphonesincluded.Cellphones,asadevice,untilrecentlydidnothavetheamountofmemoryavailabletothemthatwouldfacilitatetheinclusionof“extra”programs.Withinthelasttwoyears,thepriceofmemoryhasreachedverylowlevels.

Devicemanufacturersnowhavetheabilitytoincludemorememoryatlowerprices.ManycellphonesnowhavemorestandardmemorythantheaveragePChadinthemid-1990s.So,nowthatwehavetheneed,andthememory,wecanalljumpinanddevelopcoolapplicationsforcellphonesaroundtheworld,right?

Notexactly.

Devicemanufacturersstillcloselyguardtheoperatingsystemsthatrunontheirdevices.WhileafewhaveopeneduptothepointwheretheywillallowsomeJava-basedapplicationstorunwithinasmallenvironmentonthephone,manydonotallowthis.EventhesystemsthatdoallowsomeJavaappstorundonotallowthekindofaccesstothe“core”systemthatstandarddesktopdevelopersareaccustomedtohaving.

OpenHandsetAllianceandAndroid

ThisbarriertoapplicationdevelopmentbegantocrumbleinNovemberof2007whenGoogle,undertheOpenHandsetAlliance,releasedAndroid.TheOpenHandsetAllianceisagroupofhardwareandsoftwaredevelopers,includingGoogle,NTTDoCoMo,SprintNextel,andHTC,whosegoalistocreateamoreopencellphoneenvironment.

Thefirstproducttobereleasedundertheallianceisthemobiledeviceoperatingsystem,Android.（FormoreinformationabouttheOpenHandsetAlliance,see

.）WiththereleaseofAndroid,Googlemadeavailableahostofdevelopmenttoolsandtutorialstoaidwould-bedevelopersontothenewsystem.Helpfiles,theplatformsoftwaredevelopmentkit（SDK）,andevenadevelopers’communitycanbefoundatGoogle’sAndroidwebsite,Thissiteshouldbeyourstartingpoint,andIhighlyencourageyoutovisitthesite.

NOTE

Google,inpromotingthenewAndroidoperatingsystem,evenwentasfarastocreatea$10millioncontestlookingfornewandexcitingAndroidapplications.

WhilecellphonesrunningLinux,Windows,andevenPalmOSareeasytofind,asofthiswriting,nohardwareplatformshavebeenannouncedforAndroidtorunon.HTC,LG

Electronics,Motorola,andSamsungaremembersoftheOpenHandsetAlliance,underwhichAndroidhasbeenreleased,sowecanonlyhopethattheyhaveplansforafewAndroid-baseddevicesinthenearfuture.WithitsreleaseinNovember2007,thesystemitselfisstillinasoftware-onlybeta.Thisisgoodnewsfordevelopersbecauseitgivesusarareadvancelookatafuturesystemandachancetobegindevelopingapplicationsthatwillrunassoonasthehardwareisreleased.

NOTE

ThisstrategyclearlygivestheOpenHandsetAllianceabigadvantageoverothercellphoneoperatingsystemdevelopers,becausetherecouldbeanuncountablenumberofap