Peb npaj koj qhov kev pom! Kev ua tau zoo nrog ONMA scout android app kev txhim kho yog lav.
Hu rau
Tej zaum koj yuav xav paub qhov txawv ntawm Java, Lub Hom Phiaj-C, thiab Swift yog. Zoo, kab lus no yuav ua rau koj nkag siab yooj yim ntawm cov lus no. Koj tseem yuav kawm vim li cas ib tug zoo dua lwm tus. Yog tias koj tab tom nrhiav los tsim ib qho zoo Android app rau koj cov neeg siv khoom, kab lus no yog ib qho yuav tsum nyeem. Tshooj tom ntej yuav hais txog Kotlin thiab Lub Hom Phiaj-C, thiab lawv piv li cas. Nyeem rau kom paub seb cov lus no tuaj yeem pab koj tsim lub app zoo rau koj cov neeg siv khoom!
Yog tias koj tab tom txiav txim siab ua Android app, koj yuav tsum xav txog kev kawm Java. Java yog hom lus siv feem ntau siv rau hauv Android. Tab sis yog tias koj xav tau kev nkag siab siab, koj tuaj yeem siv cov khoom siv tsim app. Cov khoom siv no yuav qhia koj yuav ua li cas los tsim ntau yam apps siv Android. Nrog Java, Koj tuaj yeem siv lub emulator los tsim ib qho Android app. Yog tias koj tsis paub meej tias koj yuav tsum kawm Java lossis tsis, Nov yog cov npe ntawm qee cov phau ntawv zoo tshaj plaws ntawm Android programming.
Yog tias koj tab tom nrhiav rau kev cob qhia tus tsim tawm Android siab heev, qhov chaw zoo pib yog qhov kev txhim kho Android. Ntxiv rau Java, koj tseem yuav kawm txog qhov nrov Android studio. Cov chav kawm pub dawb no yuav qhia koj yuav ua li cas los tsim Android apps nrog cov cuab yeej tsim kho app ntau tshaj plaws. Koj yuav kawm Java, cov lus programming nrov tshaj plaws rau kev txhim kho Android, raws li kev siv Kotlin, ib qho ntawm Google cov lus programming tshiab tshaj plaws.
Thaum koj muaj qhov ruaj khov ntawm Java, koj yuav npaj mus rau qib tom ntej, uas yog haiv neeg Android app programming. Thaum chav kawm no xav kom koj kawm paub siv Android Studio, nws tseem pom zoo kom koj kawm Java ua lub hauv paus rau kev txhim kho Android yav tom ntej. Lub rooj sab laj CHIP muab ntau yam kev pab, suav nrog cov lus qhia, kev qhia, thiab forums. Yog tias koj txaus siab, koj tuaj yeem nug cov lus nug ntawm CHIP Forum.
Thaum nws los txog rau Android app programming, Java yog hom lus xaiv rau feem coob ntawm cov neeg tsim khoom. Txawm li cas los, muaj ntau yam lus programming niaj hnub uas tuaj yeem khiav ntawm Java Virtual Machine, suav nrog Kotlin. Cov lus no yog 100% tau tshaj Java, thiab code sau nyob rau hauv Kotlin yog kiag li interchangeable nrog Java code. Lub syntax kuj tseem tsim los ua kom zoo ib yam li Java. Vim li no, Kotlin tau txais koob meej ntawm Java zej zog.
Txawm tias nws muaj koob meej, hom lus no tseem tsis tau paub tab txaus los siv rau nws tus kheej. Rau qhov ntawd, Nws raug pom zoo tias cov neeg tsim khoom siv Android Studio lossis IntelliJ IDEA cov cuab yeej rau lawv cov Android app programmieren. Kotlin yog dawb, compact, thiab yooj yim kawm. Hoob no yog tsim los ntawm kev sib xyaw ua ke ntawm kev paub txog tswv yim, lab kev ua si, thiab kev kawm txhais tes. Hoob no tseem suav nrog txhua yam ntawm Android SDK.
Cov lus Kotlin yog ib qho bytecode uas zoo ib yam li Java, yog li nws tau sib xws nrog cov khoom siv hauv Android. Koj yuav tsum rov pib Android Studio tom qab txhim kho Kotlin ntawm koj lub cuab yeej Android. Koj yuav tsum tau teeb tsa Android Studio kom nws tuaj yeem khiav thiab nkag siab Kotlin code thaum koj tsim ib qhov project tshiab. Thaum koj xub pib tawm, koj yuav tsum xaiv hom Empty Activity project.
Nws muaj peev xwm ua rau koj Android apps hauv Objective-C, cov lus muaj zog uas tuaj yeem pab koj tsim cov apps zoo tshaj plaws rau koj lub cuab yeej. Txawm hais tias nws tsis muaj zog npaum li Swift, nws yooj yim rau kev kawm thiab tuaj yeem ua rau koj cov apps sai dua. Koj tuaj yeem kawm txog qhov program hauv Objective-C hauv ib hlis. Txawm li cas los, Nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias kev kawm Swift yuav ua rau koj muaj txiaj ntsig zoo dua kev kawm Objective-C.
Ua ntej, Koj yuav tsum nkag siab qhov sib txawv ntawm iOS thiab Android. Qhov sib txawv ntawm ob lub tshuab ua haujlwm no tau piav qhia hauv qab no. Qhov sib txawv tseem ceeb ntawm ob lub platform no yog lawv cov qauv tsim thiab kev ua haujlwm. Tej zaum koj yuav tsis xav tsim tib lub app rau ob lub platform, lossis tej zaum koj yuav tsis xav kom koj lub app saib tib yam ntawm ob lub tshuab. Txhawm rau kom paub tseeb tias koj lub app yuav zoo ib yam ntawm ob lub tshuab, koj yuav tsum paub tseeb tias koj ua raws li Human Interface Guidelines thiab Material Design cov lus qhia. Thaum nws yog technically ua tau los tsim ib qho app rau ob lub platforms, nws tsis pom zoo.
Yog tias koj yog tus pib thiab xav tsim qhov programablauf yooj yim ntawm Android, Koj tuaj yeem kawm Objective-C hauv lub sijhawm luv luv. Yog tias koj muaj kev paub txog Java, koj tuaj yeem nkag mus ncaj qha rau Java code. Lwm yam, koj yuav tau kawm cov lus tshiab. Muaj kev nkag siab zoo ntawm Lub Hom Phiaj-C yog qhov tsim nyog los ua kom tiav qhov program Android apps. Muaj ntau qhov kev kawm online uas tuaj yeem pab koj kawm hom lus no.
Koj tau txiav txim siab kawm Android app programmieren nrog Swift. Tab sis koj pib qhov twg? Kab lus no yuav muab qee qhov taw qhia uas tuaj yeem pab koj. Txawm koj kawm hom programming twg, koj yuav xav tau kev nkag siab zoo ntawm lub ntsiab lus programming. Yuav pib, download tau lub app-bakasten, ib qho cuab yeej tsim app, thiab ua raws li cov lus qhia los ua ib qho kev pab cuam. Ces, Koj yuav ua tau zoo ntawm koj txoj hauv kev los ua Android app tsis muaj sijhawm.
Thaum koj tuaj yeem kawm Swift nrog kev pab ntawm kev qhia, Tej zaum koj yuav zoo dua los ntawm kev siv tus kheej qhia kev qhia lossis app tsim cov cuab yeej. Piv txwv li, Swift Playgrounds app yog ib qho cuab yeej siv tau zoo rau kev kawm lus. Nws muaj ntau yam kev qhia uas tuaj yeem coj koj mus rau ib kauj ruam. Ntxiv mus, qhov kev pab cuam muaj xws li nyuaj algorithms, kev ua haujlwm, thiab cov lus qhia. Raws li kev pab ntxiv, nws yog dawb mus download tau.
Yog tias koj xav sim Swift programming yam tsis tau nqis peev hauv ib puag ncig kev txhim kho, koj tuaj yeem sim kawm Java ntawm koj tus kheej. Muaj ntau yam kev qhia dawb hauv online. Cov apps no pab tau thiab siv tau yooj yim, txawm hais tias lawv muaj kev kawm ntau dua li cov lus programming ib txwm. Thiab yog tias koj xav txuag nyiaj, koj tuaj yeem xaiv rau kostenpflichtig app tsev cuab yeej zoo li AppConfector. Koj tseem tuaj yeem rub tawm qee qhov kev qhia dawb, uas feem ntau yog ntau tshaj li ib txwm tutorials.
Extensible Markup Language (XML) yog ib hom ntawv siv dav hauv Android app txoj kev txhim kho. Nws qhov zoo yog tias nws yog platform ywj siab thiab siv tus phooj ywg. Kab lus no yuav piav qhia txog cov hauv paus ntsiab lus ntawm XML thiab nws yuav siv tau los tsim ib qho yooj yim XML-Zeichenkette. Hauv thawj ntu peb yuav piav qhia txog XML-Format thiab nws siv li cas hauv Android apps.
Cov ntaub ntawv XML yog cov qauv ntoo. Txhua daim ntawv yog tsim los ntawm cov hauv paus ntsiab lus thiab ntau yam me nyuam. Cov lus tshaj tawm XML txhais cov XML version. Cov ntaub ntawv XML tuaj yeem muaj ntau lub hauv paus ntsiab lus thiab ntau lub ntsiab lus me nyuam. Piv txwv li, ib “lub npe” lub ntsiab tuaj yeem muaj ntau txoj hlua. Yog hais tias tus variable muaj ntau tus nqi, ib txoj hlua txhais tau siv los khaws lawv.
Nyeem cov ntaub ntawv los ntawm XML-Zeichenketten, koj yuav tsum siv txoj kev tshiab hu ua aktiendataXmlString. Ua ntej, Koj yuav tsum nyeem XML-String los ntawm lub vev xaib server. Tom ntej no, koj yuav tsum tsim ib txoj hlua-Array uas muaj cov ntaub ntawv nyiaj txiag cuam tshuam. Cov khoom no yuav raug xa mus rau onPostExecute txoj kev txiav.
Thaum programming ib daim ntawv thov Android, koj yuav tsum nkag siab lub tswvyim ntawm Lifecycle-Metode, uas tuaj yeem piav raws li 'lifecycle’ ntawm ib daim ntawv thov. Nyob rau hauv sib piv rau C-raws li programming lus, uas muaj ib tug lifecycle, Cov ntawv thov Android muaj peb lub voj voog. Txhua tus muaj nws tus yam ntxwv, tab sis lawv txhua tus ua haujlwm zoo ib yam. Feem ntau, Android app programming ua raws li nram qab no lifecycle:
Ua ntej, kev ua ub no yog lub hauv paus ntawm ib qho Android app. Txhua qhov screen yog ib qho haujlwm, uas txhais tau tias nws yuav tsum siv txhua txoj hauv kev ua neej kom muaj txiaj ntsig. Cov haujlwm yuav tsum muaj ib txoj hauv kev hu ua onCreate(), raws li txoj kev no yuav tsum tau ua cov ntsiab lus ntawm qhov screen. Txoj kev thib ob, ntawmDestroy(), raug hu tam sim ua ntej qhov kev ua ub no raug rhuav tshem. Muaj ntau yam laj thawj vim li cas Android yuav rhuav tshem ib qho haujlwm.
Hauv Pause() yog ib txoj hauv kev zoo los siv hauv Android app. Thaum ib qho kev ua si nres, lub kaw lus hu rau onPause() txoj kev. Txoj kev no tuaj yeem siv los cuam tshuam rau ib qho kev ua si uas tau tso tseg. Nws kuj tseem muaj txiaj ntsig rau kev cuam tshuam nrog cov neeg siv thaum muaj kev ua si nres. Txawm li cas los, koj yuav tsum nco ntsoov tias onPause() yuav tsum tau hu ua ntej koj hu onResume().
Thaum debugging koj Android app, koj yuav tsum paub yuav ua li cas nkag mus rau Debug cuab yeej. Koj tuaj yeem pom nws hauv lub qhov rais cuab yeej ntawm sab xis, los yog xaiv View > Tool Windows> Debug. Nws muaj ib tug debug icon, thiab tuaj yeem nkag mus tau los ntawm nyem rau ntawm lub pob Debug hauv lub cuab yeej qhov rai bar. Lub qhov rais Debug qhia cov txheej txheem Android tam sim no thiab tag nrho nws cov kev hloov pauv. Siv lub pob Debug yuav tso cai rau koj los txheeb xyuas cov lus yuam kev uas cuam tshuam los ntawm koj lub app.
Thaum lub qhov rais Debug qhib, nyem qhov “Xov” tab thiab tom qab ntawd ntawm tus xov tooj xaiv. Lub qhov rais Debug yuav qhia cov kab ke rau txhua txoj xov, thiab koj tuaj yeem tshawb xyuas qhov tseem ceeb ntawm txhua txoj xov. Koj tuaj yeem nyem rau ntawm tus kheej cov ntsiab lus hauv tus ncej kom qhib qhov chaws. Muaj ntau ntau txoj hauv kev los kho txoj hauv kev uas cov xov tau pom hauv Debugger qhov rai. Koj tuaj yeem xa tawm pawg thav ntawv nrog rau kho lawv qhov kev nthuav qhia los ntawm kev nyeem phau ntawv qhia Debugger Window Frames.
Yog tias koj muaj lub khoos phis tawj lossis lub laptop, Koj tuaj yeem siv USB debugging feature ntawm koj ntaus ntawv hauv. Txhawm rau pab kom USB debugging hom, mus rau Developer Options thiab ces xaiv “Debugging hom.” Thaum koj tau enabled USB debugging, Koj tuaj yeem yooj yim nkag mus rau cov kev xaiv tsim tawm siab tshaj xws li ua kom USB debugging. Txhawm rau siv USB debugging, nco ntsoov tias koj backup tag nrho cov ntaub ntawv tseem ceeb ua ntej yuav mus.