应用程序基础外文翻译

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1、ApplicationFundamentalsAbstract:AndroidapplicationsarewrittenintheJavaprogramminglanguageandtheapplicationcomponentshavefourtypesofapplicationcomponents.BeforetheAndroidsystemcanstartanapplicationcomponent,thesystemmustknowthatthecomponentexistsbyreadingtheapplication'sA

2、ndroidManifest.xmlfile(the"manifest"file).AnAndroidapplicationiscomposedofmorethanjustcode—itrequiresresourcesthatareseparatefromthesourcecode,suchasimages,audiofiles,andanythingrelatingtothevisualpresentationoftheapplication.Keywords:Java;applicationcomponents;manifest;

3、source;From:http://developer.android.com/guide/topics/fundamentals.htmlAndroidapplicationsarewrittenintheJavaprogramminglanguage.TheAndroidSDKtoolscompilethecode—alongwithanydataandresourcefiles—intoanAndroidpackage,anarchivefilewithan.apksuffix.Allthecodeinasingle.apkfi

4、leisconsideredtobeoneapplicationandisthefilethatAndroid-powereddevicesusetoinstalltheapplication.Onceinstalledonadevice,eachAndroidapplicationlivesinitsownsecuritysandbox:lTheAndroidoperatingsystemisamulti-userLinuxsysteminwhicheachapplicationisadifferentuser.lBydefault,

5、thesystemassignseachapplicationauniqueLinuxuserID(theIDisusedonlybythesystemandisunknowntotheapplication).ThesystemsetspermissionsforallthefilesinanapplicationsothatonlytheuserIDassignedtothatapplicationcanaccessthem.lEachprocesshasitsownvirtualmachine(VM),soanapplicatio

6、n'scoderunsinisolationfromotherapplications.lBydefault,everyapplicationrunsinitsownLinuxprocess.Androidstartstheprocesswhenanyoftheapplication'scomponentsneedtobeexecuted,thenshutsdowntheprocesswhenit'snolongerneededorwhenthesystemmustrecovermemoryforotherapplications.In

7、thisway,theAndroidsystemimplementstheprincipleofleastprivilege.Thatis,eachapplication,bydefault,hasaccessonlytothecomponentsthatitrequirestodoitsworkandnomore.Thiscreatesaverysecureenvironmentinwhichanapplicationcannotaccesspartsofthesystemforwhichitisnotgivenpermission.

8、However,therearewaysforanapplicationtosharedatawithotherapplicationsandforanapplicationtoaccesssystemse