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1、畢業(yè)設計（論文）外文參考資料及譯文譯文題目：ApplicationFundamentals --AndroidDevelopers學生姓名：學 號：專 業(yè)：計算機科學與技術（NIIT）所在學院：信息技術學院指導教師：職 稱：2011年12月19日19ApplicationFundamentals——AndroidDevelopersAndroidapplicationsarewrittenintheJavaprogramminglanguage.TheAndroidSDKtoolscompilethecode—alongw
2、ithanydataandresourcefiles—intoanAndroidpackage,anarchivefilewithan.apksuffix.Allthecodeinasingle.apkfileisconsideredtobeoneapplicationandisthefilethatAndroid-powereddevicesusetoinstalltheapplication.Onceinstalledonadevice,eachAndroidapplicationlivesinitsownsecuritysandb
3、ox:TheAndroidoperatingsystemisamulti-userLinuxsysteminwhicheachapplicationisadifferentuser.Bydefault,thesystemassignseachapplicationauniqueLinuxuserID(theIDisusedonlybythesystemandisunknowntotheapplication).Thesystemsetspermissionsforallthefilesinanapplicationsothatonlyt
4、heuserIDassignedtothatapplicationcanaccessthem.Eachprocesshasitsownvirtualmachine(VM),soanapplication'scoderunsinisolationfromotherapplications.Bydefault,everyapplicationrunsinitsownLinuxprocess.Androidstartstheprocesswhenanyoftheapplication'scomponentsneedtobeexecuted,t
5、henshutsdowntheprocesswhenit'snolongerneededorwhenthesystemmustrecovermemoryforotherapplications.Inthisway,theAndroidsystemimplementstheprincipleofleastprivilege.Thatis,eachapplication,bydefault,hasaccessonlytothecomponentsthatitrequirestodoitsworkandnomore.Thiscreatesav
6、erysecureenvironmentinwhichanapplicationcannotaccesspartsofthesystemforwhichitisnotgivenpermission.However,therearewaysforanapplicationtosharedatawithotherapplicationsandforanapplicationtoaccesssystemservices:It'spossibletoarrangefortwoapplicationstosharethesameLinuxuser
7、ID,inwhichcasetheyareabletoaccesseachother'sfiles.Toconservesystemresources,applicationswiththesameuserIDcanalsoarrangeto19runinthesameLinuxprocessandsharethesameVM(theapplicationsmustalsobesignedwiththesamecertificate).Anapplicationcanrequestpermissiontoaccessdevicedata
8、suchastheuser'scontacts,SMSmessages,themountablestorage(SDcard),camera,Bluetooth,andmore.Allapplication
