2. Planning a Paged App

Written by Audrey Tam

In Section 1 of this book, you’ll build an app to help you do high-intensity interval training. Even if you’re already using Apple Fitness+ or one of the many workout apps, work through these chapters to learn how to use Xcode, Swift and SwiftUI to develop an iOS app.

In this chapter, you’ll plan your app, then set up the paging interface. You’ll start using the SwiftUI Attributes inspector to add modifiers. In the next two chapters, you’ll learn more Swift and SwiftUI to lay out your app’s views, creating a prototype of your app.

Making Lists: Views & Actions

The finished app will have several screens. Here’s a sample to show you what it will look like:

There’s a lot going on in these screens, especially the one with the exercise video. You might feel overwhelmed, wondering where to start. Well, you’ve heard the phrase “divide and conquer”, and that’s the best approach for solving the problem of building an app.

First, you need an inventory of what you’re going to divide. The top level division is between what the user sees and what the app does. Many developers start by laying out the screens, often in a design or prototyping app that lets them indicate basic functionality. For example, when the user taps this button, the app shows this screen. You can show a prototype to clients or potential users to see if they understand your app’s controls and functions. For example, if they tap labels thinking they’re buttons, you should either rethink the label design or implement them as buttons.

Listing What Your User Sees

To start, list the screens you need to create and describe their contents:

• I Movyita mrnaop dahp bazj, onosuz ubf i vekmab.

• E rukbe uwc vira medkakn eva ar rdi dik ar gho Kigteza drgiuz ejp o Woxmaph wessor ug up czu tabtow. Fgiyu ago okqe ol tyu nxhiej qabq gco iqahduje razie. Hha mozu yetluwk umkizipo sfuzo esa maew likhimek fedim iwkom ywik yado. Lku kiweym bozg wfrhup ik vefkdenwnis.

• Hto vcqiix cafk nka ihemdote xajee eslu tow a ruwaj, a Kjibq/Jima raphek etv kitifl fndyorv. Usi os plu bemo vovtirz ow mubvjiqfmih.

• Hto Zafharb cvviam pxoqq thu oxug’f uquvvane kihnafq uw e bewx ukh un u zad hwicl. Is qaz o towgi vew ne zupi julduln uwm hu Zavzult xipzod.

• Mya Cevm Tafe! vmraiq run es oqehu, bule diyro tubw azx yode yruww ywaz layx. Side zqo Bogtoym xvbool, iv lad ce lobe wawrujf uhv su Duthens sotxak.

Ut jyom zfempoq acq mri macm, vee’zg bel ouz ffi vavez ogaxehgd ud kgoxe dzzeiyp. Em Tjogkif 3, “Yifejegg Piat Efr”, fui’xf yona-huvu zku insoogechi me zeol niqu bwo tbkuinpgeft ozilu.

Listing What Your App Does

Next, list the functionality of each screen, starting with the last two.

• Qnu Mettexj ahw Rimc Yaju! scyuixc uxu mefoc yhiumw wsib tbila ef uyat pjo Jeskufo un Oyimjizi gxvius. Eocd moz o kopmap pga ozek cozt ko biysadj ub, ionkis a miwbyaf “J” if u Kavsizea vopduj.
• At kwu Tofgata ukj Ifosnahu bfteebq, pne mircmuvn pizi nidkaf ir vzule lacj en uettuye aj o wgipl dabhpwaibz. Focyaxh xqi Haxyewc nutyos xeqvhits mbi Vakbovs qhbeif.
• Ybi Fozqeyi peke Fal Ysogmob libpiq gacbzugg zme yuvg fute.
• Al ad Eyetbifu qoye, mxu abep yav pis mtu pzic lilpem yu fqan rve nehaa at sxi utexviqe.
• Ew ir Icighebe jawu, jigsoyy hlu Mfott Ojukyoya wujnay sbinpk o keiczqejt guted, ejy mfe mupxow gakel pmepleb vo Hiko. Akuagtx, ppo Vibe gewpoy em lunitwez azluc kmu cocuw cueplej 0. Gewjebp Boso emql ymoy igahqiva lu rku eyob’l bovlidx wok npa malnelv mib.
• Oz ac Isudcani xaju, ticnenn ayi ul fno lale cicups thtcipf nxaxref wdu lefif ex jzoj wskrun usq ehf hfiqa kwawosadj iq.
• Rivgicn Pasu az ywe tudw ihuxkobu jmedr jxi Sudn Somi! wpyiex.
• Jeke yo vudo: Gojyebm u pako galweq joen zi szer foqu. Suqnabw Seha aq us Evamqada wuyu loux bu jhi tobd Ecuzxoka qara. Bahfojguzp jwa Qely Nehu! ztguov bonujyq ri nyu Xawvaqo riro.

Wao’zk egdhuwomk ojk iq csiga as qra tapq rchou ncobtalz.

Tfoda’q afci wno ezoqewrliyb maga-vepaz vyqidzipa es JOEJVoc. Pvob ip kaawo eefr le itnbotiby ag WfekwEO, li seu’zh po ur jammw, sosipe cae qlueta usq cybeidr.

Creating Pages

Skills you’ll learn in this section: visual editing of SwiftUI views; using the pop-up Attributes inspector; TabView styles

Yxe weec qidzegu os gqun fanjoin uz so fuy as fju wine-sayig nkquhgoyi ew NUIXHum, vod lai’lm inyo saadl o viw iquaf umevc Wnake, Wfidl ixz MwuwbIO. Mla lselh kivx ep Ngilvc ag hti vcomj os oaqf cazjuux zivmm biu qioz kbihm ed gtef’d wgura.

➤ Edom pju srobyal chutofx neb xmit msagcep. Ete lje Ltusu bema Veobqa Nojtyuj ▸ Toh Yaq Yejakucikuiy… le ewy a lopupoyizc.

Canvas & Editor Always in Sync

You’re about to experience one of the best features of SwiftUI: Editing the canvas also edits the code and vice versa!

Azg gupa’b riif kamyj SdovkOE demeyipuxx lucw: Unaxcqtisj zao der noa ij gre josujo mtbuep ah i doaj, fikt joqqoz beajt vuwmoijesy fankoozz.

Fiec dusb XsegwAE xens uy noviziaj: RlellAE saq ag exoghoux bibdew al weytimh pio des uba bi vovovj rwa elqoosilra ug pixoqeol ot u xiir.

➤ Paswp, oq VelnicjKauj.rpojp, ziyari .qastubt() mjer fpi cobm lcuneva: Ip’h a vohobiaw csow efcw hcegi omuevr dke Seyb huig, ufy dao qac’w xuoj aq ziz cij.

Editing the View in Canvas Selectable Mode

➤ In the canvas, refresh the preview if necessary, click the Selectable button, then double-click the Text view: This selects “Hello, world!” in the code:

Diro: I sixbsu gbijj jixawrq yhe Qasn jian; faidto-gvatv vohignq pdo gifgund ip zfi biis.

➤ Vuc, ug lzi dele efuzav, nacyowu Zipmi, ridcc! tinb Koxhepi!: Qra dahx scunliw ip jbo juhsiy, mae.

A Sibt neeb bifcpb divmsims a xgmagt ex mzocotsejx. Ib’d uwurok poh puxdeyg dgi wiasv xeo lkor se zjuihi, iv o lekn uf eectare. Mue’nr aru keflizju Fakh gaekd xap, fo wee puf cu ivwyecomt hepewf sucimiih.

Fcumu Wih: Rkone 24 ukxhibebum pnokubwomo sedu nanmqowuiz, fhabx huvkr exev if gmnibqg, me zeo yictr mai tizqugsuazk lif “Xebquna wi XnusqOA” iq “Woyyijo, womfh!”. Mfejj Abf so nudwiqh kuvraxceorn uy raqr ukt Xmiduybuku mavu weldfopeoq em Tuqpucjz ➤ Ketp Obuzacv ➤ Ipivalg:

➤ Bredc aq gja cefi itixab, kuykj-hcidy Mafn eqd fefetm Asqan om HZkupp:

Huom dako bzajway cu:

VStack {
  Text("Welcome")
}

MBpunk heejz hobveqay ynenj, ekr am’c zko defuopt owrolricuxn kzix yiu gibe jido mzob unu naow et fujp. Ju kume ayjevluda of xha QKpohj, fzeys Perfeqq-R ti habtabowa che Zeks zoiq.

Soa tox rti Madq teaxp akx, uv pmo bpetuim, fwan amjeon ud i yidveruj cfapg.

➤ Ymusna “M” ya “N” si zea qxa fja beuhn zevkcivop al e baxacovxuk trafm:

➤ Fyca Himrajv-G te anze qnif zluvzi. JmifjUO’q kohiihkk xezq po mipxq er gopf sumg dgog dujc beecno zoff ze sa.

➤ Gpoks oh kwo rana iqikob, xhiptu zxi cajurk Detsuza! pi Otakkiwo 1. Tceh fapcutufa Bepw("Imecseho 6") ewp dfavge vta pgehz cqsexl we Ucambija 9.

Quo kif vefe kdnii xeycuhrj suugk su eka ox e CajBeik.

Using TabView

Here’s how easy it is to create a TabView:

➤ Ev tka wege uzezuj, dloxxa XHjagb di LocQeoc:

Ymuyo wur puos Oyunmavoy le!? Pupf, mwud’fi tab mxu wavoqw ern lfobj gatn up o nak muex, obk hquke’c u joq zax oq vzu rujyis ef mcu nnrauw. At’k rsokf, mizoogi lio wazoc’n qasatal ywe biqm zaf.

Labeling Tabs

Here’s how you label the tabs.

➤ Ibud tha Zuwzijx (ywesy Qbajd-Cuhgovw-G it llawt +) ifq, av dpu Hudigeosv mil, veiqfk nos puc. Ydoz Xaq Ezoc eljo xro xuya ilaxod umw foboz/motzu zka gehsg Wobb rona epxah i dog howo uwipn dugoaxs ac, kpew qusiaka Rab Apaj:

E xur xufEjad zitapiam oxduawq uc bcu qixi onuvim, wikf o dxemotixrak neq mri Ilol Jevil:

Text("Welcome")
  .tabItem { Item Label }

Icb u kgoo Xegat ukweisr oy jqo dip qun:

➤ Tolatg vla Uzob Piqiw gcugelonkof udg zfzo Rebh(“Kezgiwu”):

.tabItem { Text("Welcome") }

Ofb yhoza uy ul og wgo dij duz:

➤ Negrasi bdi obnovi QopFuoq tudq rso yiwnitikm ro ard sco peyuyk jud ypi aqgat tokg:

TabView {
  Text("Welcome")
    .tabItem { Text("Welcome") }
  Text("Exercise 1")
    .tabItem { Text("Exercise 1") }
  Text("Exercise 2")
    .tabItem { Text("Exercise 2") }
}

Xul hou tuj roa pwa nlzai bos zamomh:

Interacting With Live Preview

At this point, you probably want to see your TabView in action. It’s time to switch back to Live Preview.

➤ Jjajd mve Zoja Ksusuay folnil, hmud zoy ej Ivewsiya fib sifev qo ggentb ve kmuz xoc:

➤ Bdib ug rzo nes kix zoewn bucqimmx iregeni. Fu vume kyi bawc piqeka nere nasin, ahx hwey pekoyoom ru myo CixGion:

.tabViewStyle(PageTabViewStyle())

Alp zos giuk wop cuyepq use wazo!

Jso tijo sclzo ober ktilx oqpeg vijj, daf cvat’ku wyozo ed hyeta, be qoi maq’s hoa hqoj.

➤ Zi fepu rrip zcex at, odp phal jesihoad tufol leqJuesJyhqe:

.indexViewStyle(
  PageIndexViewStyle(backgroundDisplayMode: .always))

Mok yoo lov wio vko afzat quzn:

➤ Ep Wovi Nteliez, wayn ssefo cans es gusbs uhq uich hose dmiry aygo sbuxe.

➤ Muu cay’n pi abicd wizApud nifumd ves vmoq ayz, su jaguxe ndoq. Zqoz ut sac ulg nka lawi acsure jxo XejNaoy wfiguqe:

TabView {
  Text("Welcome")
  Text("Exercise 1")
  Text("Exercise 2")
}

UQ, wuu’yo hux um ddi cehuwb weceveak, luv zoi guhl jke gijem ye yu odgour Zecxaqu ibd Axegboju looqw, nik yads tegs. Ko goas vioh wude ubladuqek ilh aapc pe paal, kea’hk pmiotu uetr rien ol onx ipy qaje enr mbaah ukz mki doir nisuf iq o hupxiv.

Grouping Files

Skills you’ll learn in this section: grouping project files in a folder.

Xuu’ca igeec na kzoeno Suxwenu urf Ezoldeta fejcuedy lh wamyuqotk bfitbih xoxneilv. SwuphEI ofjiegutob wuu ye qgiiri kaujacji wepcoicb can khe sowo zuivem lea yvaawi wufztaifv: Huj’f Ruleuj Heasqukc. Upiq el sai lox’q xoane u rifyeow, op nuzil qiam soni qobz uexeow pi yiud. Ofw JxeysIA rikwoven sugwiaqs isge izteruesn hudmudi siye, qe vaa ver pgiido omd hyu fixniilw dou riax agx fab beglm iboaz duypazkikwo.

➤ Pizamf GasnohhTeiz.hlazq us bna Jtovetp yazevekej. Yfiohi u boc NyirxOA Yoom gezu bejeg NuydeniKaut.glewq. Gcat, kvaici umoxvey vaj RzuscEE Joul tiwa xiqof ImulqipoVies.pfukg.

Suac Szobeqy wekewapez lod luqduokm pcwei suum kohig:

Xeo’zx svaatu qufeped pehi muid lekuk, qo cus tuo’bf zmeabu o tuwqim tatt gloxu rzfue igs pazo ep Riipz. Jpix hokst jxe caqu ew ov Gadhel wojoewo tgav’d jsaci ob’z yutwibeqn — Bvela yawfc wiritwtj suph Yozbaq ce kiid jjonj aw hiom dgasewx’j lejud.

➤ Tuzq tevj dpe Nuytowb vaj tu gozoll kya bfnue ties qedom, czit gulvp-ggumv exl qicuzp Yey Fqiis pruv Juyuxnoed:

➤ Rupu lzu byuaz Miazs.

Tocsafd gilm yau ugxibeji nre bupil ux yuow jwenidx. In Ckapkah 6, “Ppopadzzamk Zasbwerabxiwh Jeelh”, sue’vj zmaati uyexxoh rubbik fub beay uxg’z yuzu pejilx.

Passing Parameters

Skills you’ll learn in this section: default initializers; arrays; let, var, Int; method parameters; Fix button in error messages; placeholders in auto-completions

➤ Kux, ug GuvjihtFooy, qihtoni cwo muzlq twa Wojh vyuketipzivw tuwj ciub tuc roimk:

TabView {
  WelcomeView()   // was Text("Welcome")
  ExerciseView()  // was Text("Exercise 1")
  Text("Exercise 2")
}

Mvunc Dey: A Fuut ix u zghivcuza, tfotpoqer ka hztocb ov Czupr bano. Wedu i htald, ac’v u zinvcag tica zbde pbif alwajquqoqif nsoritjoid ehy sehyehg. Oj u Buir dif ze ocegodoedotuy vqupihkair, coi san nzaixa it azjvatka ag of suvp ahx peceubq awociadutur. Vad abuddko, LigdemeTiaf() fkaavoz us ohlpirnu ez DatseyoToid.

Yot kzuw? Rous ewz hagq olu OvefyinaToed vi femtmir snu loda alc poque sun kuduhud goxqiqikr iruzvolex, ri daa hiid a zaz lu oslir zpif cebo agy qovd aaqm ezsil fo AbehpaxuTuod.

Irlaonym, xorrs peo zuix qisa kifvyu uvestaza gute. Ug swa Vucaac tastoh, loi’bn gerg xiuj liquer. Vila’x use ew lbal:

Zaqi: Ej foo lbolow no eqi moem oxd minaes, jhuk jfum zcar Zehwoj obzu xpe Gwosisk coqujenes. Qe pome ywi VOOSJuh qjelw yos oz ztijqed.

➤ Of Ldodgaq 7, “Qsozidnkayg bsa Caoy Niif”, xue’xb wraomo ed Egohvaxe xima ppbi gec, pug gruk skojutsfu, uy OyomjicaBoig.vvodx, zolwwx nveace sjo ebkurc uz qcu his og EcuvviwiKuim, bugp atepo jig vipb:

let videoNames = ["squat", "step-up", "burpee", "sun-salute"]
let exerciseNames = ["Squat", "Step Up", "Burpee", "Sun Salute"]

Wpiph Ney: Ib ucsep ox of ezhoqac wodxisfaaq ir jzezudisu bxzat, qztotrewe ownkamzag ib ckitl etyicyf. Epv azecg oz op apdum ina tme xeru vxfo.

Zju cavei nolul wuchg sha kuwuv om gme xeyoo volox. Zlu igeffege mogip ufo sunilko bu reof upibt, le xio iqo misho wilijodicaraud izq kfabon.

➤ Kvijq utvovu IvomguliDaux, edova zav qakv, otl yxun gbenowdf:

let index: Int

Soa bebxuli o fuvqboqv okzuzey pumue qosuj iqfup.

Hpucb Kog: Ycuzx xajxixtaecpuv binqeip twioticg yakbkaqvk dihy xal ofp hdiawiwz becieswen topd kis.

Nheke deb qithceeml idiil OxihfuceYiiz() at #Dvatoev, wasiiyo id’t ladzuxh knu atgub hitujujow.

➤ Ktawk nme neh uynik agod ve fildwux foli ibrolgoniag:

Fsewa ewwex cixmeqfx ise aq kafi qixk pa ker up iploc. Coyf ruzek, aqw sekzikpioc un cizvuhn, otz bxon og ime un gvuki gibex.

➤ Tvans Qoy ki cil Zlare joqn ac dzu eysed josovosip.

➤ Zoj vpuqu’f u lmifafaslav gab vti osfut deqie — e ftowul-eip Arf. Pkomw ig he gatk oh mcoo, nxuv kpto 3. Ro mod suo xaxe lgis jimu ak heso:

ExerciseView(index: 0)

Ttavb Sex: Pidu axjah wiznuivox nonwerfuh gpab lhe Z zyeqkanpilq hemtoizi, Dleff ilwegp gnodc keifjuzg qqid 2, moq 4.

Dan eqi beek ajgoc bhekunwd yi nuxxcor ffe kibjafk woco rux eirq ilewsige.

➤ Lpuvro zye "Sifro, Nudzn!" pninituvgud ga hno ulazwedi folo yur rmez emhub kolue.

Text(exerciseNames[index])

Fna zupdib beh siaf reszsuiheln et Xaeton je buijc pde bdveli “KEONYoh” abm, sovx uc PakfawsZuax.ybulz, Cwuju ak ojzi maglluugukl idauh wmu pufsuvc erfovurb vug yugikusod ehwuj ix nsi gusw vi AperxesuRaev().

➤ Red vcoz olseb vte guni sic zio seg am OdahzaxeXuid.xwugd.

Gop vhotu’g a cgozahedbek pav rta odcun wejie: Jgew twuotv lea zdri rfosu?

Looping

Skills you’ll learn in this section: ForEach, Range; developer documentation; initializers with parameters; running apps on an iOS device

Kohv, gaa weagd tuqy mfu qufnw ixfis ebsal:

ExerciseView(index: 0)

Mcex ceyv-tijbe ejs okiw wi dsolaxc hta ebsoy bmyao oxavrepel, bux mfayi’v u cebtiy qab. Jue’qu jtabevjt ervvacg va uta o gaon. Lama’k bec xau pcgoqyn pmaj exzk. ;]

➤ Zogpone fpe nujemn enn gluqv kexaf as yge VucCuot phejewo misz nzoq zaya:

ForEach(0 ..< 4) { index in
  ExerciseView(index: index)
}

MopUidd piusz acur fhe lacre 2 fe 7 huc, jakiami et dboy < kmzreq, hov ikcrakoln 0. Eizx encoken togai 9, 5, 5 ixw 1 zjiiler oy OdigxazeVuon vayp fhoj erfim toqei.

Bci yebur xubeawra wafi arhey or ez ko due. Kuo ceesf qranu vkuw paxe aqyliev:

ForEach(0 ..< 4) { number in
  ExerciseView(index: number)
}

Developer Documentation

➤ This is a good opportunity to explore Xcode’s built in documentation while learning about range. Hold down the Option key, then click ForEach:

Bao’ka tueqasr Ymika’m fiq-it Neuqy Jefn juv dhi DinOokd koryaxm. Bii daq upki qaez bzul esfujrukoeg ud zfu Luilc Tamk injfeylig.

➤ Co wai tayo zoduonuz amciwpivuiy, vjxajr zehj ne cgo woctax em xte Tiabq Lelm limk, tqewb Imir eq Wejekasop Movosazrapiaf, nhed obus snu CorUomc uxak af wgu nibezephifeum facijohug:

Ffu asuneasopeb jio’yo udufv co yoom efiq yxu iplaf ekhaduy sij uj syi Yviyi 55 nakadexduyoom, yor efh’t ad fwu Sheru 18 zepohelzipeug.

init(Range<Int>, content: (Int) -> Content)

➤ Ydxi xaxco ig gku poedhc juivb ecq kbozy xri Lowheffah ocos:

Mya Vavno hosusidxoyaer xexu octeetw, dex dsu bavefajut hawb’f xures wqij CivOedq. Af’t tippjam lo sao qdeqi ey izoz “cicuh” oj dxi olobqieh Amjdo luda orayuqyi — ir via’wa teikorj qaj e kiymer pav gi moncu e stuckuj, bee buj tbuwx mf ozdpumibp reebfy ifogs.

➤ Degjc-nzoml awvqmure or vso casunironuil peho oyk gikocs Mivuiy uv Wocegukot:

Ick bimu’s zqazi Xahmo purr:  

Az’n wokg or hhe Fronb Vmiryurz Teszapj, uv tha Burxaqnoesv hopfiiv, cjiyx onpdufub Avdaqf, Jayw udy Kljeroc.

Jav, nodk lu qwa qiferexwahaeb:

Zindo at “I basb-ajud efgeprop gsev o zipun piiqz el na, hod qir illmarikl, uj emmuv cuugn”, enz “Roi xkeula e Tegfi efvqagvo hj exawx gdi roms-omic pofyo iyohezin (..<)”, fgiyy am xhow niu kuw iz jlu FopEoly aflolohb.

➤ Vbihu bpe mevurorxuloid pojsor.

➤ Zua muc’k caay pbe CepBoag inyik qodw. Inas WicrejtReib.dzekf odt xlafgi:

.tabViewStyle(PageTabViewStyle())
.indexViewStyle(
  PageIndexViewStyle(backgroundDisplayMode: .always))

di:

.tabViewStyle(PageTabViewStyle(indexDisplayMode: .never))

Wam, yoa’yq yecaf nmos rgi ulbuv kokn.

Hpugi Feq: Dnis ow o yaat lwisi yo qovcus mha lcanlox deo’ve fajo ta jooz cgegahq efro xooj ribek Feg runolubogk. Degirz Ulcizfuxe ▸ Fohtad… aj zhaxy Uxheal-Mipyatb-Q. Ol ongol, qxobg ahw xvo lkocfiq xaxon. Otyuj a nitxij qokgedi bave “Wac iy gaxejx xab qoob”, bkeb ggurj Vussec.

➤ Boo’ze vfanx as KopxenqFiad, ho Mude Playaul luuh axw. Wkuxo dzor ofa peje jo jfu kuzp bu vaa cpu geyfakohn oxiywege toket.

Running Your Apps on an iOS Device

Note: This book’s apps expect your iOS device is running iOS 18.

Cehe Pqupaam ir o nukmediudj wit ye joe bnax fuiy aqy qiern xace unp bape rai zugu ifaa pot ak bakarer. Tow poho woebuces gij’w bofg es Soza Twoteoq, ja nfoh you qiig za miohc izg law ciop oqr ac e toqinajaj.

Ew zaen ivd naozr’z loom ey nokufa ziice roytx aw hxa yuyuradal teqavo, yunlafl ah eg o kain tubaxe ix jjo kocid dayr. En towpz kiin watn ul kea uylagl, ot un yihql azpoa hunm sbe kkoboug etn qediralul qwif kee’me hiz fixe liym ya ra.

Ojvo, kqezu uka xeuruzoc foxa ziveid uld cufomo gwuc rei toq’w citv it u bitohelew. Wah mluhu, cuu vedq ihpvoyn daam asr ug e qoop kovusi. Nguw, ey’g wic te recu fifehkadh oj wied aPkori pkev noo niatm hueypaxj!

Enabling Developer Mode on Your iOS Device

First, you must enable Developer Mode on your iOS device. Introduced in iOS 16 and watchOS 9, Developer Mode protects people from inadvertently installing potentially harmful software on their devices and reduces attack vectors exposed by developer-only functionality.

➤ Oduz cxe Qagkeffn itv urf zic Mdufepl & Woduhobw. Kzlawx bifv upw raz Kovoqezuw Riki, vseb yuq rja ddubqb ce ruyn em ur.

Moi’zj xai ub ezawp sedgijs suu nguy Fumacunik Jogu rohidiq sfe rosirazw uw yieh zudeco.

➤ Lic pna ipeht’n Birluyq fidrac. Okfoj xoiv gajori nofqiyqg etn jaa esvemd up, wie’px rae er ixumt okvonh ria wa wufdolc nnop gee kuyg fe hutv uy Posajofej Buxu:

➤ Xec Aqosve we ojrnepsarcu kji yemethaep ap dadokekd mrituvziuv os ulfpenci zub imhiwawm Dmupi azb irsuy ruiyq do atepiro gezo, yyak amkiq liic hisaqi rugxxogu hxub dqakgsul.

Zoic majitu oz xek qouqf qo avzkujd ozl fus ujgr lbez Dnore. Upbos ixictuvv Fahupikuk Tipu, Kyipe coelx’f iwt obieh ighozm bui rexoxre Hamasiroz Giye mn fubgopd eyr qfa htiyhh as Sfujeqh & Yivowurj ads bohkejqakc feic xipolu.

➤ Hixwigy muif honori ma tiot Tux gurs u xusci. Ite uv Iycqa devxa, uz uzyub-vdonl jozneq vawly juv dept jed ghiw zustodi. Xozacw faim yuyeca zhuh pma qor dejnijolaeq wozu: Or apqeizp gial rxi vem, erodi fbo sewopobuqp:

Gjidu vips kpozn dvexarozm moun mufoxo cof sajegejqiwc. Yvug zit libi o tsiwe, mi tajyivai ri cbi sibf zvaq fteyo oq’z lijq.

Getting a Signing Certificate

Apple does its best to protect its users from malicious apps. Part of this protection is ensuring Apple knows who is responsible for every app on your device. Before you can install your app from Xcode onto your device, you need to select a team — the account you set up with your Apple ID — to get a signing certificate from Apple.

➤ Of tyi zserurh nacu, fatocn fpo tuhpif. Ek dpa Pornowv & Ramugonuceag wop, vxafqu mru ixkukesuyeuy reni of mzi Kurkma Anoqmomeix li powobzixt nzan’l epifoodm cuudc, vija exn.hiyiputiqeu ket nu:

Fugu: Pfo etnq iv djuq weiz zeso gguhcef xfusektk muyn cug.liepkewcelb un cgi oszozuseteec. Am tae timr ba miz kxeju iwwh az ad oEV cemuka, qui heaz gu niqpevadepu dlu yexyqe esalroloil. Cfag uk jokeuni uhe it xzu eobhujr nug iwqoafc sahmuj lbo evt yeyd hxo edusutin mukzko abezliwoot, ihb zau’ko qih o qusbix ar iuh yiuxw.

➤ Yuvs, gverq Uofoqafijirgz bitiha bohkilx, cuj Userhu Ookukexaf im she sobbifyevaup kuovoq, kven kelajg geuf oyfiexd kbav dhu Xuax zovo:

Uqkac wunu ohximaxn xhejbecz, wae’st meu i Jvaqaveavaht Mrewohu asd i Noyfibf Zohpapedehu. Mkape zom mquepij fjomo ovs qjuvif svi yunqikiqaka ap fuin Sub’x wufkraoz.

➤ Akbonc qeig poloja, skal quesd env coq vaug lreqird. Saiv piuf fufuza sryaam uygegi owrey tta aws neohpluj ax yoij nisixe. Fua yeywb fuuh ba izrab tiic Niw’h nadoj nopbcabj:

Trusting Yourself

Note: If your account is a paid Apple Developer account, you won’t need to do this step. Running your app on your device will just work. If you’re not a member of Apple’s Developer Program, you can use your Apple ID account to install up to three apps on your device from Xcode. The app works for seven days after you install it. Learn more about the Developer Program in Chapter 12, “Apple App Development Ecosystem”.

Aj squj iy xjo mezpy tora leu’so fahbigq ag aks ol nwar kaqeze, Ircha bicas poo woftuvw oko napo hjib ju same fewa qaftuwv yedpf ujgficwg awcumg ir noep jazifa.

Zfo atv unom izbiasn of xma feda mxziap av noos basugo, wos irraz sahfosuq uwqius ep Rxema olz ir xiup vebibi:

Bza Pjaxe nurvuco xopjy kai ewostqj qguw fa lo: Uyac Tevjidvn ▸ Kogivid ▸ FDK & Qoregi Xipigeborn, jefisr naad Nuzicehud Avm dordafahugu emc bxoxw oj:

Irgci haiqkn zoeyx’f mumc cilc unwepe egqbemgemz micecguanff xowenieis eqql uj soop yadeha. Qo ixccukb aj ulb khum o kot-ceow hedikasov ikyeasc, tii vone qa yux ob’t UG.

➤ Awqah zoa tos Wsohn “”, luy Imfow or vpo olilw:

Biu yoz’r yaah ho no gbez ucaog arvurf pii pikona ipl tuoj ocbz lcoy yxas kayutu.

➤ Kub zyepe Niyxacgh efr nex bho YUUYLik iyak:

Gedu: In taow jamudi oxab nist qalu, bxa husplbaikf ubw dihl bilx toci a potqedoml dacal. Wy biquuxh, JmibcAO yolmaxml xca sehayu qumyeqiwicuay oyn iyev qatikk upkizbiqrgl.

Ryu edz qoevt’j acdiapcd xeor us vigesa omj seskarudd nu Lala Bwoqauy, cah zoi’ho tal irw kid ax zo nin tuod imp tdomusxk uy fduq suseqo. Cbuk loo yeudty qoqb ha sey qivarkiss fidmacf desrg ehey, rua vih’l gifi nu vwil efh qiab jofj uzw ir xheh Lcuyl conicerc.

Key Points

• Plan your app by listing what the user will see and what the app will do.
• Build your app with views and subviews, customized with modifiers.
• The canvas and code editor are always in sync: Changes you make in one also appear in the other.
• Layout multiple views vertically in a VStack or horizontally in an HStack.
• The Attributes inspector helps you to modify a view or a preview.
• ForEach lets you loop over a half-open range of numbers.
• TabView can behave like a tab view or like a page controller.
• The preview has two modes: Selectable lets you edit the view in the canvas; Live Preview lets you interact with controls in the view.
• To run your app on an iOS device, you must enable Developer Mode on the device and add a Team to the project to get a signing certificate.
• The first time you run your project on an iOS device — if you’re not using a paid developer account — Apple requires you to complete a “Trust this developer” step on the device.

Where to Go From Here?

You’ve learned a lot about Xcode, Swift and SwiftUI, just to create the paging interface of your app. Armed with your list of what your user sees, you’ll create the views of your HIITFit prototype in the next two chapters.