外文翻译
原文1
A
droidApplicatio
Fu
dame
tals
A
droidapplicatio
sarewritte
i
theJavaprogrammi
gla
guageTheA
droidSDKtoolscompilethecodealo
gwitha
ydataa
dresourcefilesi
toa
A
droidpackagea
archivefilewitha
apksuffixAllthecodei
asi
gleapkfileisco
sideredtobeo
eapplicatio
a
disthefilethatA
droidpowereddevicesusetoi
stalltheapplicatio
O
cei
stalledo
adeviceeachA
droidapplicatio
livesi
itsow
securitysa
dboxTheA
droidoperati
gsystemisamultiuserLi
uxsystemi
whicheachapplicatio
isadiffere
tuserBydefaultthesystemassig
seachapplicatio
au
iqueLi
uxuserIDtheIDisusedo
lybythesystema
disu
k
ow
totheapplicatio
Thesystemsetspermissio
sforallthefilesi
a
applicatio
sothato
lytheuserIDassig
edtothatapplicatio
ca
accessthemEachprocesshasitsow
virtualmachi
eVMsoa
applicatio
scoderu
si
isolatio
fromotherapplicatio
sBydefaulteveryapplicatio
ru
si
itsow
Li
uxprocessA
droidstartstheprocesswhe
a
yoftheapplicatio
scompo
e
ts
eedtobeexecutedthe
shutsdow
theprocesswhe
its
olo
ger
eededorwhe
thesystemmustrecovermemoryforotherapplicatio
sI
thiswaytheA
droidsystemimpleme
tsthepri
cipleofleastprivilegeThatiseachapplicatio
bydefaulthasaccesso
lytothecompo
e
tsthatitrequirestodoitsworka
d
omoreThiscreatesaverysecuree
viro
me
ti
whicha
applicatio
ca
otaccesspartsofthesystemforwhichitis
otgive
permissio
Howevertherearewaysfora
applicatio
tosharedatawithotherapplicatio
sa
dfora
applicatio
toaccesssystemservicesItspossibletoarra
gefortwoapplicatio
stosharethesameLi
uxuserIDi
whichcasetheyareabletoaccesseachothersfilesToco
servesystemresourcesapplicatio
swiththesameuserIDca
alsoarra
getoru
i
thesameLi
uxprocessa
dsharethesameVMtheapplicatio
smustalsobesig
edwiththesamecertificateA
applicatio
ca
requestpermissio
toaccessdevicedatasuchastheusersco
tactsSMSmessagesthemou
tablestorageSDcardcameraBluetootha
dmoreAllapplicatio
permissio
smustbegra
tedbytheuserati
stalltimeThatcoversthebasicsregardi
ghowa
A
droidapplicatio
existswithi
thesystemTherestofthisdocume
ti
troducesyoutoThecoreframeworkcompo
e
tsthatdefi
eyourapplicatio
Thema
ifestfilei
whichyoudeclarecompo
e
tsa
drequireddevicefeatures
1
fforyourapplicatio
Resourcesthatareseparatefromtheapplicatio
codea
dallowyourapplicatio
togracefullyoptimizeitsbehaviorforavarietyofdeviceco
figuratio
sApplicatio
Compo
e
tsApplicatio
compo
e
tsaretheesse
tialbuildi
gblocksofa
A
droidapplicatio
Eachcompo
e
tisadiffere
tpoi
tthroughwhichthesystemca
e
teryourapplicatio
Notallcompo
e
tsareactuale
trypoi
tsforther