资源描述：
《有关android技术英文文献翻译》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、``英语原文AndroidApplicationFundamentalsAndroidapplicationsarewrittenintheJavaprogramminglanguage.TheAndroidSDKtoolscompilethecode—alongwithanydataandresourcefiles—intoan Androidpackage,anarchivefilewithan .apk suffix.Allthecodeinasingle .apk fileisconsideredtobeoneapplicationandisthefilethatAndr
2、oid-powereddevicesusetoinstalltheapplication.Onceinstalledonadevice,eachAndroidapplicationlivesinitsownsecuritysandbox:lTheAndroidoperatingsystemisamulti-userLinuxsysteminwhicheachapplicationisadifferentuser.lBydefault,thesystemassignseachapplicationauniqueLinuxuserID(theIDisusedonlybythesyst
3、emandisunknowntotheapplication).ThesystemsetspermissionsforallthefilesinanapplicationsothatonlytheuserIDassignedtothatapplicationcanaccessthem.lEachprocesshasitsownvirtualmachine(VM),soanapplication'scoderunsinisolationfromotherapplications.lBydefault,everyapplicationrunsinitsownLinuxprocess.
4、Androidstartstheprocesswhenanyoftheapplication'scomponentsneedtobeexecuted,thenshutsdowntheprocesswhenit'snolongerneededorwhenthesystemmustrecovermemoryforotherapplications.Inthisway,theAndroidsystemimplementsthe principleofleastprivilege.Thatis,eachapplication,bydefault,hasaccessonlytothecom
5、ponentsthatitrequirestodoitsworkandnomore.Thiscreatesaverysecureenvironmentinwhichanapplicationcannotaccesspartsofthesystemforwhichitisnotgivenpermission.However,therearewaysforanapplicationtosharedatawithotherapplicationsandforanapplicationtoaccesssystemservices:lIt'spossibletoarrangefortwoa
6、pplicationstosharethesameLinuxuserID,inwhichcasetheyareabletoaccesseachother'sfiles.Toconservesystemresources,applicationswiththesameuserIDcanalsoarrangetoruninthesameLinuxprocess````andsharethesameVM(theapplicationsmustalsobesignedwiththesamecertificate).lAnapplicationcanrequestpermissiontoa
7、ccessdevicedatasuchastheuser'scontacts,SMSmessages,themountablestorage(SDcard),camera,Bluetooth,andmore.Allapplicationpermissionsmustbegrantedbytheuseratinstalltime.ThatcoversthebasicsregardinghowanAndroidapplicationexistswithinthesystem.Ther
