資源描述：
《應(yīng)用程序基礎(chǔ)Android Developers 畢業(yè)論文外文文獻(xiàn)翻譯.doc》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在工程資料-天天文庫(kù)。
1、外文原文:AndroidapplicationsarewrittenintheJavaprogramminglanguage?ThecompiledJavacode一alongwithanydataandresourcefilesrequiredbytheapplication一isbundledbytheaapttoolintoanAndroidpackage,anarchivefilemarkedbyan.apksuffix.Thisfileisthevehiclefordistributin
2、gtheapplicationandinstallingitonmobiledevices;itsthefileusersdownloadtotheirdevices.Allthecodeinasingle.apkfileisconsideredtobeoneapplication.Inmanyways,eachAndroidapplicationlivesinitsownworld:1.Bydefault,everyapplicationrunsinitsownLinuxprocess.Andr
3、oidstartstheprocesswhenanyoftheapplication'scodeneedstobeexecuted,andshutsdowntheprocesswhenit'snolongerneededandsystemresourcesarerequiredbyotherapplications.2.Eachprocesshasitsownvirtualmachine(VM),soapplicationcoderunsinisolationfromthecodeofalloth
4、erapplications.3.Bydefault,eachapplicationisassignedauniqueLinuxuserID.PermissionsaresetsothattheapplicatioiVsfilesarevisibleonlytothatuserandonlytotheapplicationitself一althoughtherearewaystoexportthemtootherapplicationsaswell.It'spossibletoarrangefor
5、twoapplicationstosharethesameuserID,inwhichcasetheywillbeabletoseeeachother'sfiles.Toconservesystemresources,applicationswiththesameIDcanalsoarrangetoruninthesameLinuxprocess,sharingthesameVM?ApplicationComponentsAcentralfeatureofAndroidisthatoneappli
6、cationcanmakeuseofelementsofotherapplications(providedthoseapplicationspermitit).Forexample,ifyourapplicationneedstodisplayascrollinglistofimagesandanotherapplicationhasdevelopedasuitablescrollerandmadeitavailabletoothers,youcancalluponthatscrollertod
7、othework,ratherthandevelopyourown.Yourapplicationdoesn'tincorporatethecodeoftheotherapplicationorlinktoit.Rather,itsimplystartsupthatpieceoftheotherapplicationwhentheneedarises.Forthistowork,thesystemmustbeabletostartanapplicationprocesswhenanypartofi
8、tisneeded,andinstantiatetheJavaobjectsforthatpart.Therefore,unlikeapplicationsonmostothersystems,Androidapplicationsdonfthaveasingleentrypointforeverythingintheapplication(nomain()function,forexample).Rather,theyhaveessentialcomponentsthatthes
