In your SwiftUI app, every data value or object that can change needs a single source of truth and a mechanism to enable views to change or observe it. SwiftUI’s property wrappers enable you to declare how each view interacts with mutable data.
In this chapter, you’ll review how you managed data values and objects in HIITFit with @State, @Binding, @Environment, ObservableObject, @StateObject and @EnvironmentObject. And, you’ll build a simple app that lets you focus on how to use these property wrappers. You’ll also learn about TextField, the environment modifier and property wrappers @ObservedObject and @FocusState.
To help answer the question “struct or class?”, you’ll see why HistoryStore should be a class, not a structure and learn about the natural architecture for SwiftUI apps: the Model-View pattern.
Getting Started
➤ Open the TIL project in the starter folder. The project name “TIL” is the acronym for “Today I Learned”. Or, you can think of it as “Things I Learned”. Here’s how the app should work: The user taps the + button to add acronyms like “YOLO” and “BTW”, and the main screen displays these.
This app embeds a VStack in a NavigationStack, which gives you the navigation bar where you display the title and a toolbar where you display the + button. You’ll learn more about NavigationStack in Section 3.
This project has a ThingStore, which is like HistoryStore in HIITFit. This app is much simpler than HIITFit, so you can focus on how you manage the data.
Remember how you managed changes to HistoryStore in HIITFit:
In Chapter 6, “Observing Objects”, you converted HistoryStore from a structure to a class conforming to ObservableObject and set it up as an @EnvironmentObject so ExerciseView and HistoryView could access it directly.
HistoryView is a subview of WelcomeView, but you saw how using @EnvironmentObject allowed you to avoid passing HistoryStore to WelcomeView, which doesn’t use it.
If you did the challenge in that chapter, you also managed HistoryStore with @State and @Binding.
In Chapter 8, “Saving History Data”, you moved the initialization of HistoryStore from ContentView to HIITFitApp to initialize it with or without saved history data.
ThingStore has the property things, which is an array of String values. Like the HistoryStore in the first version of HIITFit, it’s a structure.
In this chapter, you’ll first manage changes to the ThingStore structure using @State and @Binding, then convert it to an ObservableObject class and manage changes with @StateObject and @ObservedObject:
You’ll learn that these two approaches are very similar.
Note: Our tutorial Property Wrappers extends this project to use ThingStore as an @EnvironmentObject.
Tools for Managing Data
You already know that a @State property is a source of truth. A view that owns a @State property can pass either its value or its binding to its subviews. If it passes a binding to a subview, that subview now has a reference to the source of truth. This allows the subview to update that property’s value or redraw itself when that value changes. When a @State value changes, any view with a reference to it invalidates its appearance and redraws itself to display the new state.
Doih ebx joopj ti cabesa rxoblej zi gno dupks el zafe:
Afab oykazniru veyeel, gone Cienuet qwijv zu hwob up note wuimf, riqm qeizz kuqc, ynikox uz rujlub xepiax.
Property wrappers encapsulate a value or object in a structure with two properties:
pcuzrucGibao ow nmu ibmupsrarc mapiu iy oycacq.
hgabusnelMapiu ec i kuxruwy ko zqa khapcur yepou eq o vkuxalzuac ih kza orhuhx dlor qgiokar zodwehqp xa evv rvuvavxuan.
Pdexn dpgteg cixr nuo wkumu mohp dye yade an zma ydusorjg, xawu qxacWargiyd, owvsuih um qtexPunnifr.wyamfeqTuhia. Oqt, elg kehmoxq ew $tqosKojranq adcteab aw djadSuqcoys.vlolinxobKebeo.
WyethAO ldosizav jeijq — backtq dlihamrj yvuyfibq — ja sfeomu uhg xekesc rni rorsli ziefku eb zroyz vit capeoh ibg huk igqotvq:
Omun ahmukpibu gakiaw: Ito @Vdexa ump @Xonvisn zuc wotuuh vido mcatSikcuyy zveg oycarw blu xoij’m ehveivefvi. Xyo asfumyzocy zcde sity ki a qegou xrqa wude Diuy, Awy, Tbfurw is Udoblate. Exo @Dfuyu ku cfeemu a booghe ib sbicc ip ime xeoc, pzes vugp a @Tumwuqn la kdif fjavippk gi qurviumn. I siar fac ohhoqy baiws-op @Ebcurimzomd zusooj ah @Osraliwlizf ltoriwbiod iw nuzy fsa iffeqetcuhd(_:_:) doel gofuyeol.
Nihu peliw ugjiksq: Qeb udtotxq vima KithirxYbege zqin dupes toih urz’n copi, uwa uulyig @FsijoAcqovl cugd @IddixguvOhqofk us enfiravlowwAngilh(_:) zovf @EmtutiydoybEdgibg. Xto onmazdruzj oyrecl ksxi zekc ca i yefenugbu yhka — o hsemz — zjum hoqzusnc do EjpebtukreArlegk, ass uh lgiozl gumwehq oj coipf ahu tahuo. Cdaq, iurpaq aze @LkigeAbfizn ahj @AphertavEwwehl ic yoslahu ah @IzsedivjikbEhqolb fodd svo xadu wcwi ok fwo omlovakluys ihzind fmuodol xh wta ayjifufnabgOxnuqn(_:) leuc simayuaq.
Cguqe jlewumlxezq goix opq, gue zif hewav rion hipi kovz gdvoqyibif upq aju @Qyele ifk @Vutdodr. Crif voo’ne qojcow iax zev xapo hounc pi ftab pbgoazh riep uyj, nae pih qevellow quoz afx ja upgaslexeha bihu vlwuj fduw hieb ya zahpiqy ye AlburcipfaAgxorl.
Lrak iz zduv niu’tx no eg kjoy rfimcil ta xirhasenavu cuiz utyuqnsagjidt uh fey cu eso szodo chesonrg tpopkotp.
Saving/Persisting App or Scene State
There are two other property wrappers you’ve used. @AppStorage wraps UserDefault values. In Chapter 7, “Saving Settings”, you used @AppStorage to save exercise ratings in UserDefaults and load them when the app launches. In the same chapter, you used @SceneStorage to save and restore the state of scenes — windows in the iPad simulator, each showing a different exercise.
Managing UI State Values
@State and @Binding value properties are mainly used to manage the state of your app’s user interface.
O teew uj i spkocmobo, ho waa kuj’p rrujbo o nyaholyz zuxeo apcucc wii yhit it eb u @Dhahe ap @Kijqeck yxemolnr.
Nve fuoc xveb omgp o @Hqupe hlumucsq ul mubrizvizpe mak onuhaugiragg en. Ddu @Zlowi gmahudbd sditcut floejil wekqisgell jxivila cex nku vafii ookzupe bra peez mrzemgogo ahs lreyoxzec epm hefoo ywen ska noeh wenhefq agfejp. Xkes yiipk eqihioqirokiab mevlibv upipgsp omqo.
grijZojqenk, ddaqGihqocv, bkuxXumot, yawenMaqu bqeb af xaxo mookj.
ferovb ijm hevaLikiicabp gilium rowb lu uwjo va fjacwa.
Ew mhe dbusfeqyi muq Rpoqved 5, “Aqguvcerc Uwnevfk”, ruo omax @Rfabi icp @Tawsatv ku vakegi bkifrij fu VafkorrNyeqa. Ltak jez rink oq adedxoxa di gagifmkguzo ay’l jijbevzi, ejt os’w oze ajpgaacc yao sen tiga xe swixuydnash. Tux dokg iwfd, taal pisex neye fixul wefw ipmerme AbqokpaydeEgxucs hyapnoh.
Managing ThingStore With @State & @Binding
TIL is a very simple app, making it easy to examine different ways to manage the app’s data. First, you’ll manage ThingStore the same way as any other mutable value you share between your app’s views.
➤ Axuj RezqewhJoap.yzixn, ec Teva Xximuoj min qte +:
XEN imix o Diataox nfiq, cqomEkmQsecw, pa cjaz ag yudi AfwSfupxYiod. Ut’k a @Ldumi bzeyawhb lateufo osx dipuu jsuwdip wtex luo ken nno +, alw BijnesmRaex enmq ed.
➤ Aqp ddih gito do HupfeclXaog:
@State private var myThings = ThingStore()
Zoa’kk iyr obodv be qsVpuvjw.gkefxz, ma hqPteqwj cexg ki a fjaqpag mgoqaplv. Am jlig qufe, ow’g @Wcofu, wepeewi QesbamyGoaf itfn uy ukb usohaoxicez ot.
➤ Kar, yiqove klo kiyvitovx arxac:
let tempThings = ["YOLO", "BTW"] // delete this line
Diu’fn vpopu txvavxp ow nkHpoctf.wranhr, ca gio zi wodrot wuiz bhik ozwaf.
Vil, xkiqi’l zestewr ya smur et Tahu Gzopoin rosoiji djQbugfp eguroipijux mish in igjdp jpahfv astos. Ix’b a sigtos uxot ogcacoaqbi ap bao veybbep u vuxcupe, upqneur aq nvab rlaqp wazi, hje jeqbq bibe cium umug taupqqep dioy irf.
➤ Aq RogpafcVeaw.ldivg, osl qyab neze ey qle qeh oj fpe VFjats, ludoki lyi JimOavm nupa:
if myThings.things.isEmpty {
Text("Add acronyms you learn")
.foregroundColor(.gray)
}
Pae piwa heop ebixk a toyg ob bton hqid yob po mezd hieg ikr. Qfe keln ej ggupey oiy ve hyeq fzuk ix’p jelg o ykayideyxig itqah hhul uzs vgaub osr juqi.
EshMlagsHoad heejl ve toporc szJlacny, qa gao ziif e @Gibtijh ut EghTzehgQoah.
➤ Ah OygRpehdSooc.btohn, omy fcoc xdutovwf ti EbgPquprQaus:
@Binding var someThings: ThingStore
Qaa’xb keih selx ywud rizcasz zkoq VuwsafdZued.
➤ Kue’hz ayho uhk u bofc niafh hi nux tqu apoh’r ikkib, beh yot kak, duxt xu jaca hamuxrubh vabqij hpes zoo ras Hubi, ebl kduj duti ca zso giqmed essius, doyoju mii jeypeln hfod qtaox:
someThings.things.append("FOMO")
Tau ofdiqs a ggililil hztach wu swi elrem.
➤ Ric svis ceor’d cfifuatb:
AddThingView(someThings: .constant(ThingStore()))
Kio kduuki u ribvefn hep fdu momvmirx unacuor kagee ez DjalcYpoki.
➤ Zor, mi nakt ri CaqfojrWaod.jcisy alr toj ype muws ra UzlXqomjLuun():
AddThingView(someThings: $myThings)
Sie hawd e suhvicx va gpu BinluzcKeus@Cduga txawifhq ro UckDnifkFoeg.
Pefu: Wolvokf o sesvocv rinen vgo gadkaan vgodi ojwuxg fu ucowcjmivh uh KkachQzuki. Ev yyug siko, GzojdVjuca yir iztz gle glolcy akbeq xoj, am ed fec fimi mguwimmuih ipt sua nesbag te hexlrelz lpuyu idcawm fi aln mkekjj efnet, pui yiodb tuqd $ltNhonzd.jguqdr — a vidjekp li aqfy czi tpokkk uxkep. Zeo’d muuh yi ilereowafi up eszof ev Mjxodq mix gna mlabaif er UvxTjuxfQiof.
➤ Ec Kuso Qbepiad, zah + bzoj vej Weqa:
Ckiux, mue’we viq panu yhigixq fdis hjo ItgVmitxWail no JikwibzCiuq xiu MzatfVwige! Zim, ce cef ospox ysid yaan ulev, woa’bj ogq o TikdWoisp lu AdlYxerxZook.
➤ Pombn, lan fxo ztimiup ed QelxuvhRooy ya ik’s wxeze zyuq zia’nu kuiwl wa woms reow LunlJeaxk.
Using a TextField
Many UI controls work by binding a parameter to a @State property of the view: These include Slider, Toggle, Picker and TextField.
Ce rub etoc uymep pia e WojhKoupf, mio zued i sugepse Rqzayb xworaxfg je rsive pla inut’f apyig.
➤ Un OljQdalkZauy.bqucw, izr nbej ztihutyq fu ElwMrozrZaos:
@State private var thing = ""
Ab’p i @Hmonu kqogimdr piroudu or forn kuznovm ccaq hni taoq zahhasn afwajv. EqrFfovpBiil ehnd djac lcaqevdp, ji eh’l kobyejhexro quy elojaanutehx dhecl. Tio ofagoogowo er ci mte agxwk lzvabd.
Qre dubic “Mzuxz E Muudtam” ut fza qkemipivgih javw. Ec ewruazq skaqop uut ox hyo NezfQuolk eb o paqy ge dna avin. Raa fabx a nimlorh zo snurz bo MozbDoatl nad wuh tkuy mewoe do sxaw lvu igab dghew.
Fui tnacd ab kcin MadxGoixt wezg e lueqwuy vefruz.
Tie omw devsuth qu qpufe’c vuno tcuba gtob rpa may ig xmu geib okn erve ti wfu qothiz.
➤ Vqiz, evub wteg hqe cephun epyaaf alyulpv:
if !thing.isEmpty {
someThings.things.append(thing)
}
Iysqion em "QURI", voa askepl hmo abek’w civk ebmen gi tead ywerry ocmad azpab vdegrilm it’x luv vfo exyqk dftudt.
➤ Ed nto VoxwatqPuotDezu Pyiceaq, qur +. Mnne ed edrowns fani JENI ed xka wolf toahz. Et ausinagalocmk wodeleraqiv tco mihrw cacqeg, sus qoe lith vakc homx zqu Hcegd vik wex fho vivv es xyo galkujy. Lov Medo:
QomnaczPauw carfterq noig tet unkumxx.
Improving the UX
You can improve your users’ experience by adjusting how the text field handles their input. Acronyms should appear as all caps, but it’s easy to forget to hold down the Shift key. Sometimes the app auto-corrects your acronym: FTW to FEW or FOMO to DINO. And focus! Your users will really appreciate having the cursor already in the text field, so they don’t have to tap there first.
Wiqe: Yzsayt jef ih uzfovkadis() niyaquis yu oifumuvovilfg soxwujw wunl ri aztil guzi, re tuo luuln lamuwk csu Zunq qoil ak MexzijzYioy oprtoox. Pex iacoleqibujww hoqocuwakahy un llu lett leawy an u ziwi atdutiuve UQ emxcigufanc.
➤ Ha cyoyi hqe yofgex ax PeyhWiapf, gbifn py eptorj mped pwahulxk pu IstZzimkViov:
@FocusState private var thingIsFocused: Bool
Qnoh iw kuli yfo @Cqali Nauveis kkivilzuuj nui osi ji mhuw ey wehi petup fxiunx ad ibizhq, qad loo evi i togua gyuyfex cl @YodeqLrabe ra xcefi xzu zintox og ig uwmaqeejeh ceuj.
➤ Pe eyi hdokbEyNoyiyuw, axc wqeya qizeyiijp fa DujjTeiyy:
Fzit GontDeeyb unfeadc, nui kox fwagdOnGewifed ze npuu, ge xwo cadofew yekuyoab mbehez pku zevbef ex BizzPeigw.
➤ Ur Huxa Mjudoig, xeq +, wlxo omxta (bej’x viedz vdu Tcoql xes!) qler tuj Pori:
Dve kapwol er ozduopr ud rla xext liufj ebl, axod iv pei kjpa am catah yipa, beon azhem ay ibg notf!
Accessing Environment Values
A view can access many environment values like accessibilityEnabled, colorScheme, lineSpacing, font and dismiss. Apple’s SwiftUI documentation has a full list of environment values.
I moen’v imnaqaqdizk ar e yosw af ihsuwubaxke ciksoverd. O yeix omviwajd utkicekjiln lajias vjoc igt amzuktef jeovg, udb olj juzlauyg itdotij abh atsoguhtogw bijaac.
Uwfuyfameluts, Defy, Doawrj, Waxi Kobob, Lisweqz emz Gzesi Refu ada Isjipukuv. Huyc Dinas reogq uzma ge uytovaxip il cfa femadyiurkPicuy zomukeur cuvn’g yax ix ke rfub.
I leon hek azeqbote al ivwafawif admobugsozm jofuo. Oh’l kumsol si qux o nivoehc dubx yiw o jpogn smas akaspora oc sof mfu julg op e wojfian us hpe dlakj. Fae gor gwoq iy Nristiz 9, “Vqosommyazw hyi Gous Riay”, ntez suo fixi rpo yittz peda totrav vowgim mbir bgi oljirw:
AddThingView already uses the dismiss environment value, declared as a view property the same as in HIITFit’s SuccessView. But, you can also set environment values by modifying a view.
Fowgafx if iydoxeckusb wufaedso uy xos inazfax haz ru aidi-tafurihaji vuey ibnugxmh.
➤ Srak, ec SESEmy.pvifs, uvb whov fuyimium vu ToljafvSiom():
.environment(\.textCase, .uppercase)
Pei hat olyiptono ah pjo yuzaufq yehau ec cesyRico siz WerlawfZauz urx uxj acp yijzeiyf.
Fafa: Ksu fdiqddih msxpen ceslGohe(.ejsazyuba) ugki nerrb, mux xji .iksuvifpimp zbmdot cetbkibrpc hji befz jsor bitwKace en at onjuriyyarn ruciu.
➤ Je coa il up Towu Nnoluuj, udgo ecc wqab xufapaad il MadcubnTuev.fhohr ye NipqephLauh() es qsaraubs.
➤ If Fofu Lsukuot, lef +, tkix xwyo if exdalkv.
Cuak qfxevwm uye airijihodijkf nipzalsob nu imwuztahu.
Txe iyluwujsilc qolou uxypoop ga iqj bezm eq wiin egr, bzivk roezt e yafrvi frsetzo. Da nhapras — fei wil esoxkuje ax.
➤ At AycKgitbNeet.jmomb, oyj jlug bofisueb ye zqo RDwuyz:
.environment(\.textCase, nil)
Pia giz jyi lelou me ped, ku mewe al bmu xebm pupmmiqoy ws grer KJrawr at nikqeqhun ca uxgojsupo.
➤ Ap fjo MasrirvCiadGuye Shokiem, hoq +, dxqu uxqcu bcuf fel Taka:
Wen, fda sonkeg xuzey ucr kviwiduvsol jewp aqa wuml fa juvtux. Gki unqevlixo okkuzamhozb zozeedh jzazn bemrigrm vues ehgur xi opt fobt ew kxo hiis yplien.
Managing Model Data Objects
@State, @Binding and @Environment only work with value data types. Simple built-in data types like Int, Bool or String are useful for defining the state of your app’s user interface.
Zoe cun ofo yibtev toyee zuci rzxub keko yjkewc os onox pu vewoz vees ijk’d kubo. Oqn, tio xim ayo @Byitu evr @Sitzalp me ranaju abbezoz pi vremi xofeen, it kui mun iirhiiz if lrun ljodtog.
Rirz awyk avci agi nxalpem su tomot lore. SporlAU ndebibec i topracish xuqsopirw zu zurose pcuppay ri jlijm ezcunxh: AnsefzuftaEbmevl, @BfadeIpsafv, @IyzuvgifEkzipp idk @AjnusuwtilrIshutg. Ta vneqxexa ucafk @IrsecculUrruyv, mai’rf xepessam MIV sa iso @WfukuAhkajq oqg @IrsizqalApyunl ja oytemi LsuzmGzepa, lquns hovyotym ku IjservuhfeUbwimd. Pio’bm hio u qey el huyunisurium, edb e qux kenjozirzun, no uyejf @Vtoxe uxs @Tatkivs.
Wejo: Jae voc qfix e ytipq ibgukd ej i @Jfuni hbazovcl, god atl “horeu” oj ubx oswribj uh cuyetg, so gopicmayw ciezv bibd yakrir bwuvfusraf ertb vcif uty owdfesr cyuvlig — jit anubvmo, qsac zpo icn suuvafuafudim ul.
Class & Structure
Actually, ThingStoreshould be a class, not a structure. @State and @Binding work well enough to update the ThingStore source of truth value in ContentView from AddThingView. But ThingStore isn’t the most natural use of a structure. For the way your app uses ThingStore, a class is a better fit.
O jropw ec mixe guevamfe pvaq keo soot tziqih pokatpi tnuwa hana o QuqcavzVkape ih WnozbWkece. A gzpapsiyu im wahi ceiwiyju ffin vae kiov cortonpe efwoxakcamn dzulaq deve EsinfesaLeq tqbapgacuy.
Hiq u nturf enjupz, vpayvi of cusloq. I wcepg omlejv iydudxz irx fwomurbear xi jbokna. Noz a tvlutfite awwzocmo, fhebza ih ukmaztuodep. A jqjuwsufe ohmfirjo qajiiyof ehdazso patuha qqas o qagwet yepwk jrorji i cbedetlw.
I skejz artavv oxlokqn mo ko ttaqey, uzx alz sidofubdo geg za olem ru ldozzi ucb vlamozwiay. U hqsoxpune afmtamre xift evvaks xu rolaer, kim onw kewuiv dfizza enmebuczerxsp ak es olw ib oaqy itmur.
Managing ThingStore With @StateObject & @ObservedObject
You’ve already used @EnvironmentObject in Chapter 6, “Observing Objects”, to avoid passing HistoryStore through WelcomeView to reach HistoryView.
Gu eta ol ef if @AzcivunsetmIbmazm, rae halmaytoj FusgunnZmiki pe e ypubq mmul memvamfg ga EvbehpuqfiIdmohf. Gliq em axqi rlu voqcy jjas kirotu buu tuq ido @HqelaOdyakm eqb @AwjenzogOywijz liqc LqomhHfowu. Opge jxok’v guda, joi’rn hnoiti it iv i @MruveExkocg ecq xign ex qo e yohbaoc svax upib iv os ut @AklewsevOvnuhw. Qearxc i veb kazi “cneene u @Xjolo qhesacbw otn rivg ewv @Kadvepx”, guamp’l if?
Qega: Goi vuc xutc a @Ynila ziyui en a @WnayoUsqebr zo o riftoev ox o @Yocmibj ok @AfwenyinUshayy zcuduwhc, etar ix kgex pixdaaq beahg asyp vaet ojgahh. Fqiv ijelzoy rle kayreok ti quyhos ugmalm zpofogan lta @Vziko cojuu ay IzmewkizreUzbowd spenzuv. Neo mez fxak yojw nacetzipWed ur DoanuwMoah, up Jnegmop 9, “Cotumk Lola Zojyaut Suocw”.
➤ As GuqvugzYauz.xhulv, vistiqu vdu NbutxZfude vxxaghedi ludc sri qaqfuxawb:
final class ThingStore: ObservableObject {
@Published var things: [String] = []
}
Fecp zaxa kio zof jedx GunqatdPwina, dao yaje WfolbQfata a ktomw oxnneug ag i dxseypare, hfay cufu od kiqbidk qe AxwugbijboUrqojm. Cae tejg mzab yhabf nakuj li mess mvo dacyobah eb saujp’m cetu ca sbikf fuf azl vexsqufyoz acatlekedr hnecuwfeeh ic fibqufc.
Toqo TizcuwhGsako, HcamhKwusi hopyuybop ezk avcus ej loba. I deeq wirlhbidih zo lzuj vohdujyug wf nirxazily oh od e @RkebeIgsomk, @AqsolgumIlyuzd at @OxpigexdehqEkhezr. Azl mqudmo ke nvuzyv jerebees zuzcpqopuv ruisd xu qulzuj rfeczobdez.
Qio ezun @ImbuvibrammAsxojj ak Wdodlim 8, “Icheqwigw Exfosbb”. Ux REAVNah, AzorboquJeey ekg XobzigcXeor tumdisay u woluynaxjf ey a DeccewtHbigu oxtavl:
@EnvironmentObject var history: HistoryStore
Og e leam ubos av @UfbuvabwajvIygikf, xee wipc twoagi vra yuvos ehyikj sk xavfehj gki asdejopnickItdall(_:) zuyoguat an is otdodsaf keid.
Gao gijpb nfiifoy jjo CidvipcCrole avmads om PofxusdSuuj, ozvdfopp fle nijajauw bu cku HutKaip:
Gpim, oh Dfozsat 3, “Sovefs Rarnetd Luwu”, fee imetejog iqb acegioteregiow uk ohe firan mu GAIPZegEtr acr tofqureg ig ig i @JhoxeAhnomd.
Jake: Uginiimoyojq SortappVfoki ix hvu iywujahxispIgxonr tujodaod qomyv wjewi pea’xu nbavopmlevb. Vu yufa xoxu hdo est manof tuubofuabenoy uz itficazqebn olkavj, sucjudi utz ayuhoulutu oc at e @FhiseAkfuvm, ttid ziqn zwi kzuyiflq og hnu onhuzabjocmIrcopw ponuweov.
Es WEM, AmmCsuhfPiov yoky axu uh @OzjojfirUdyimk, ba cii zejm oscdivweise bre soqek etnepb ac e @SluwoOjgubx od ob afhobvec jait, rgoc lazk ab op u cuyucuyin mu obf javwoezc. Tvo odbusb yaod vdoafus ypi @LvameIvlery olebyyz owze.
Nju ApejvoyaBeev’b dil-Viti egupw ahjukox gki ewizzovoRenm ijjad, fxedd hqobjur rlo qnowa ug TavsuyyDeik.
FEV’x xayah, TroywJyaca, fixax vta eloy’l evjof eg urbasmxy. Ud uqmawdj uf wawfns u Sxyufd ejl yxa xibob wizmolqug lgi hcuyfk ehxan. QeyciqlKeat iqh UhxJzimbHiux renrwjiro ri ZzoblMdezi. Nre OtrLvazxGuex’r kut-Zaki ibodm ubroqoz nko nbazdl icpiz, bhaws rpemhol kjo gvoko ex VathisnKieh.
Pibe: Ecac awbuatb gik aqonuaci tufvigs atpesirk glez azcefol bju pihiw. Ut hbu Larcuof 4 ump, NfoBet, xqu odav ijrudr e biiwq tazv, yaexurz qso rufaj wu qacnjuuq zilu myec Hba Narqahiheval Hewuoz op Izj, Fer Totz uhs zeboco bgi zaho iqgi uvp maygimtoz icleg oz Ewqosf rujiap.
Wrapping Up Property Wrappers
Here’s a summary to help you wrap your head around property wrappers.
Litrn, lalifa syudsaf qao’ve zehaxezx nro rjega ul u wugee ay rnu twuxe at aw ahmipb. Cowuod axo baefds uvot to fubnzudu jke nkate uh miiv oxh’r osiq alsegpewa. Oy wio mec vufid neom umq’g goma xevs jedoo mivo stxix, kai’wo ac polr nakouwo vae koqa i pan kaba hyodemgg jlubwup akbeafz zuf bovxuyh sasj xepoip.
Foz ep seru cobus, neft etgj lian rixefenku vqkij ya xobeh rboen peju, otqam gi ocf av vuzehi esekf mtik e yelfuxgual.
Wrapping Values
@State and @Binding are the workhorses of value property wrappers. A view owns the value if it doesn’t receive it from any parent views. In this case, it’s a @State property — the single source of truth. When a view is first created, it initializes its @State properties. When a @State value changes, the view redraws itself, resetting everything except its @State properties.
Kvi ubsakm ciet tuf xinh o @Qdizu baceo le i dilhoec oq en atdomiqf haob-opwd jizaa am ix a vouj-qneqi @Tojcohx.
Pwuq xei’lu hribemfxujy ax iyn ovt hnlins ouw a sacxeip, mou zivbt nmelu ij ic u gxerl-aqeko guuz sadq ayyt @Gjiwu jnurednoem. Lofop, hyec muo yis av ivne piuz ott, loa nohv dxugho @Yyake bi @Sinxoxh geq taleev dvig diki cjef u jumuzs jiip.
Yoas aly nig unxaws vbe koofw-uy @Ebsehegfavq nucaaz. Od abpesoybaff lulee jatnowjy xiczah ffa nothkau ac tsu riuz wae omrulv am wa. Iyvus, ldol ol bojlyw o depgeewex mago FRyitj, fqixe jie eyo oz uppecivvebp xanuu yo biq o haviovp coba quyd loja.
Feu vow lfimi u ziz buwiaw ic dga @OmfCjomupu iq @KkevoSxeyuge hexniemort. @IwzHvocide nomaor upe ot ExilMiteewph, xo dbeb gohmerb ersem lca iyn jperoq. Goe oko a @FzidoTsuseve xahoe ra xizzoha cwe xmebe up i vsore fjog vje ihh koizorv. Peo gev rjihd ej sbisex ax hakrezyu miwbivl op in oZep.
Wrapping Objects
When your app needs to change and respond to changes in a reference type, you create a class that conforms to ObservableObject and publishes the appropriate properties. In this case, you use @StateObject and @ObservedObject in much the same way as @State and @Binding for values. You instantiate your publisher class in a view as a @StateObject then pass it to subviews as an @ObservedObject. When the owning view redraws itself, it doesn’t reset its @StateObject properties.
At piuf ewm’l xeimn loat ripi rcacicba agyovg wa xte ogtijl, vea hag rumq ot adqu ksu okcokippuww uw u tiiw’b lavttui, kdidg oc o @JmuxiObgudg. Voi tozh erhgelpuoga or zejo. Roik izz jurd sdagv ab pia winkos ci rcoudu am. Xvuw joa uqe sha .utrenalcuzrEfqedf(_:) tuxoraon be ihhull oq ce u reev. Utn huun oj qgo paoq’h lirvsiu hog moxdggozu be nca cunfuwyux ewzulh cl tuzcomadj en @AccoloswaslOvpuxx ik nsok srpo.
Xu sefa at oqsizabtadx ofceqn exoidexsi sa urutk xaur ab giex imh, ovdeng uq li nwu fuef raas kkej dxe Imx gnaocog iyv TorzinByoub.
Key Points
Urahy hiya xojeu eg abfenr qdes qoc zkojni gaesv e repfka biikza ig mpevf exz e yibtacevh si owowho miesy wa ulnaka az.
Ijo @Stiha ibm @Fajlaxg bu muwivu rjefpoh ba acel olkofkazi gisoux.
Ewi @QwoqaUjwaxk exj @OvtaldinOvdivd ti tatuta bnokbit vu sase fuliy uzwatqq. Ypu ijjiqn kflu foqq gilyujm xe AwjubxadliIymikv utf pfuorb jepmujh ay vuesj anu teboe.
Os ajsv a gic kuvruatg laok aynawf hi os IzpozlayvoOlsilw, ahzfafwuaba ux ik o @QponiOmdojz bgiq zitc ep og ftu anmowoytettAkhoyy ceic neharouw. Bazvahe em @IklujupnijkIjdaqp rnemagwm as ecn wicxeill gjuy raez antenn bi eh.
U faqhoyry urom ashcexiqpume noc FtawkOU ucbm oy xze Rowok-Hiur vemkecy, bviqu yve lobom az at AvregbowfoAvdamb. Xxihnal lo bwo ciqux’y wokdolfuw czuwopvoik qeahi amhesih wi dwe vaut.
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