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1、畢業(yè)設(shè)計（論文）外文參考資料及譯文譯文題目：ApplicationFundamentals --AndroidDevelopers學(xué)生姓名：學(xué) 號：?！ I(yè)：計算機(jī)科學(xué)與技術(shù)（NIIT）所在學(xué)院：信息技術(shù)學(xué)院指導(dǎo)教師：職 稱：2011年12月19日19ApplicationFundamentals——AndroidDevelopersAndroidapplicationsarewrittenintheJavaprogramminglanguage.TheAndroidSDKtoolscompilethecode—alongwithanydataandresourc
2、efiles—intoanAndroidpackage,anarchivefilewithan.apksuffix.Allthecodeinasingle.apkfileisconsideredtobeoneapplicationandisthefilethatAndroid-powereddevicesusetoinstalltheapplication.Onceinstalledonadevice,eachAndroidapplicationlivesinitsownsecuritysandbox:TheAndroidoperatingsystemisamulti-use
3、rLinuxsysteminwhicheachapplicationisadifferentuser.Bydefault,thesystemassignseachapplicationauniqueLinuxuserID(theIDisusedonlybythesystemandisunknowntotheapplication).ThesystemsetspermissionsforallthefilesinanapplicationsothatonlytheuserIDassignedtothatapplicationcanaccessthem.Eachprocessha
4、sitsownvirtualmachine(VM),soanapplication'scoderunsinisolationfromotherapplications.Bydefault,everyapplicationrunsinitsownLinuxprocess.Androidstartstheprocesswhenanyoftheapplication'scomponentsneedtobeexecuted,thenshutsdowntheprocesswhenit'snolongerneededorwhenthesystemmustrecovermemoryforo
5、therapplications.Inthisway,theAndroidsystemimplementstheprincipleofleastprivilege.Thatis,eachapplication,bydefault,hasaccessonlytothecomponentsthatitrequirestodoitsworkandnomore.Thiscreatesaverysecureenvironmentinwhichanapplicationcannotaccesspartsofthesystemforwhichitisnotgivenpermission.H
6、owever,therearewaysforanapplicationtosharedatawithotherapplicationsandforanapplicationtoaccesssystemservices:It'spossibletoarrangefortwoapplicationstosharethesameLinuxuserID,inwhichcasetheyareabletoaccesseachother'sfiles.Toconservesystemresources,applicationswiththesameuserIDcanalsoarranget
7、o19runinthesameLinuxprocessandsharethesameVM(theapplicationsmustalsobesignedwiththesamecertificate).Anapplicationcanrequestpermissiontoaccessdevicedatasuchastheuser'scontacts,SMSmessages,themountablestorage(SDcard),camera,Bluetooth,andmore.Allapplication
