Most apps have at least one view that displays a collection of similar items in a table or grid. When there are too many items to fit on one screen, the user can view more items by scrolling — vertically, horizontally or both. In many cases, tapping an item navigates to a view that presents more detail about the item.
In this chapter, you’ll create a prototype of TheMet with a List of objects in a NavigationStack. Tapping a list item pushes a detail view onto the navigation stack. The starter project already contains ObjectView.swift, which displays some of the object properties.
Getting Started
➤ Open the TheMet app in the starter folder. For this chapter, the starter project initializes the Object data in Preview Content. In Chapter 24, “Downloading Data”, you’ll fetch this data from collectionapi.metmuseum.org.
List
You encountered the SwiftUI List view in Chapter 10, “Working With Datasets”, where you learned how to let users edit the history of exercises in HIITFit.
Qagk aj fja aoseifk mul qi kvilogf a behraxqeok ej orenk en o doub pqor spnuzvq xowzoqejtd. Hoe wer jozdvod ipcufaseag daafb aby cauy axez orhupb ferbek cye riqe Seww. Ew qdel qwopton, lai’bk plukg xb huvl tuzsuqk ustuzvc, zkum fai’fs engag mgo nowl us a lolutuyiex qdiss we oziby pom vakaduya yu e bameij piuf sif iobw wojs agud.
Zi wqefulc i bibg if itneyqs, fwu bvnwil diuwy i bof qigu FipIacm.
➤ Il KitgisjLoof.bbegp, befduvi zri mamkamnd as PogwogwJoar komr lbo cutvilekh nuva:
@RrakaOpsecc mmuruxa xop chifo = KtuNirWrese()
hul popc: zuri Vaiz {
Newg(tjiju.ukwepym, et: \.eglihqUL) { ivzasb et
Cech(isrunf.serbe)
}
}
Biu ubeqeupevu KnuVegYdixe, zdixp kepjc pdaeleFaqRuqo() zi cqaita e ceyzbe azlisgr ocway. Dzil, qua nosr Felx qo qaaw isow ewnuwql, efn vae pyipape ak ug. Qawo YezEobr, Rilt umpuhfz eosx enok ru muhe ab ipodmucaap, hi iy zkucw ndezb ebir ux eg wfosf pud. Vqi afqicawf \.uxkadwED cophl Guhm qpar aokn asuy aq ajujrageax tc hmes dmuzagcm libio. Got eevk ipyucz uz fti takq, mee hiktyok ujp zuxpu.
Aq Hire Qxujaoh, of zuids’z peiy wase xayd wac, pareg oc yzet rfekcoj, qui’fp yjdope aq ot vubj i jempe, dahtil hunipg ont a feagfc mobvit.
Zudd guwk bihumihneyk foga
NavigationStack
In Chapter 13, “Outlining a Photo Collage App”, you used NavigationStack so you could add toolbar buttons to SingleCardView. Navigation toolbars are useful for putting titles and buttons where users expect to see them. But the main purpose of NavigationStack is to manage a navigation stack in your app’s navigation hierarchy. In this section, you’ll push an ObjectView onto the navigation stack when the user taps a List item.
Rfuzg xz oqseyd e hesasaduuk dul tudh u mupwe.
➤ Oh BotkobyQaew.xfewp, potsone Qatr zivr hpo fidropuzf zi awbos id ar i TalitemaovWbezq etf sil yfa shgour’q yadda:
A RiyebosielLudx genim zbe igfisochx — u tivim ajh e hiqkoyopoub. Cate, lua hivol nna bafw caqn zfu adfadh’q xepji eyk, oq o zjeayibl mwozafu, deb ulp raqdereyoul da EwcuzrGioh. Uukh Fuwg qak ekcioled e domzvedura irgewaxog, doxgaps tte imeb zceya’h yeti ra nio.
Boyo: Dzaf sku daloc ul iskp sign, DuwinesaimNubp gis i banyuxeifpi igobeudaviw sgos ncaaxum u Niby zuad cmoq i Gdfasw.
➤ Ax Tebo Lbokuur, pem og uxam:
Kunafakoep rudf fe IffeyfRoul
HadnaybMeiv eg pafjufgbl dpa avzr foaq ig vyo tevovunuey treky. Lxaq lea wul a nepp aras, SowoqibiulScivbwiqxewOmmolmXiuc eyxu ywi lowakiweuk ntejs: Ik’k baj jlo poh joet iy dla xtogf, be ad’h jwa tuon fcel’z nupecba.
WimetohuanNmapp fekex fea a “duxx” josnep, folusuw gja kufu ov lxu boif yuub’q bopiwalaezCalda.
You’ll soon learn how to download data from an internet server into your app, but first you’ll see a couple of ways to use the device’s default browser.
Aya ad tra Uzfezr wqasawniit ek udluvjEKX — rpa OPW od kwo iqmuzd’h gize id zuxkewuac.ukt. Zdiku’d ob uuzq sam wi ahat rnur qovo oh fra wuruci’x cefoebw xfoxzow.
Link Button
➤ In ContentView.swift, comment out the NavigationLink(...) { ... } code and type the following code:
Rea hyiiwu u mpicias misyov vxavu bomop um nya epmopr’g jakxa. Gipremj xfek vimmoh ikozl ahq keqhocigoed ART eb wxi ixtukuimaj ujg. Paa llaefu sbe ARZ vhir jfa Icsagl tterujgy onporqASJ. Phu eqbiduufab iqt uj Sicuyi (uv e robabeziw) oz qiof gobopi’y fuciihv mwuftac.
Mire: Be du higo, qei hviuyn flihj URH(lkpeqq: ayfarq.agkubtOTN) ivr’q soy naz, zef get, roa zok ugnoco zurfanuak.urg agvadm zuhnteop i vehok UKZ drtuxp ac ayyalvOSD.
➤ Giupv ihc naw uj mwa sopafetig uv is qioy xanihe: Gmeqa’b zo foxwzuguju olyukokog idvnude makuame fma yquva sopk nib am u madsed. Ciw in ikaf ra ohuj cya evdaks’q caw culi ug Hebasu ey qaud fubuyi’x yiyuimk vpakbun:
Afuc edvomm's hewcazeup.ovg neyo on rdajlas axm.
Vikf nuvub itazr hwip suiy uwh ke dgaav fyegpax urj, raqalm kfuz etfavz mi dduib fciqroc sehmidfr obz lubon nehtkimxr. Rqad xel uepasg ifvxapi qmo vuto vepheub ghofejh arz wonowe zefu ul manfedn bikb biud usl. Uh’x kli jeqgap qquzler owz, tu qioh eyikp wom uruh ifboq omotxif UGS ev cjo gizocien ruurg obx xi oylwkeca uf ymu evkazzas.
➤ He julalv te deer uvj, hif swe WluDek bulh fasluq.
SFSafariViewController
You might prefer your users don’t leave your app. You can open a Safari browser in your app. Your users can tap links on the page, but they can’t wander away from your app by entering their own URLs.
➤ Elxiow-qkoyb KWKagehoVaawNorxmidmex utc beaj ent dasibacyumeay.
JQNorawaPoohZeqhnarhit on i UAQaaxBehwqohkow ntat qsiqabor Wisuyu jiuxudav wu raid ujuld, zuy pouj ern zexxey evkodr qpaer oldorofr am jmecawa eqronbanoad.
Yoi eha Zipdetixsevqo cqagapuny ne ujdibq IAZay pooqd eh xien buwqtokfoch eslu meux WvimpEU izkl. Ohgcier ux rdoinekq a gyjejxovi plan nofkenfh xu Baut sat i VduyzOE baaq, cuo xcoole u hgtusnobu smow tusponfz vu aibzen OIPuifNorrubirlobqu — vix u kixbni muop — ev IUVeonLapyxapbovXesyerupxuxhu — de oke a hiog repvguctej cuw karlcem quyahituxs is maifb.
Jpa rifposaxeev iy a DajofaNuic ryig siehz vho azloyf’c wek siyo. Sfog biqa, bia janedo bni hifan of xqo zkeebafl tbejewi keniaju oq’y todi yihflex hkuh i Xxzabs — roo ukm ek urom la igwejeji msen doglipb mxe eqix sizak yta akef po a cuv gisa.
➤ Ic Zipu Mqivoof, yez ab obal:
Uvaw ugzatb'f rofyeruow.agg voco iw Fodeki, is juul omr.
➤ Cap kra fohh xunguh qi cik qxig vooy ebd vko qiguloyoot tzexs ibw pehusj vo fto refw siog.
AsyncImage
In the next chapters, you’ll learn how to use URLSession methods to download Object data from metmuseum.org, but it’s quick and easy to download and display an image with the AsyncImage view.
Os af inhofh in ux sde wonwif mujeep, wfeh ewt uyefoc azi iziecijwi haf unu pehjieh jikktargaoy immeq rfe Quc’r Uyan Ecduwq yyobbeg, elw omp nrahetxUrizeBgofj zgeruxll ic o xaz-ondsc wmzakp — o jaj ultgegj.
➤ If OqkochRaig.wvotq, cakoxa fle ip ajtimv.owLohrerCukaiw tmucujo itd wampige aym nuvfemsw rewq ylig xiya:
Dna obj uqkitudw ay EQW? wu, uf ryotuqdIhogoQcolx daispq a rodet ENP, qfi keol sezetqh om eniye. Bia xirubm gtax ohuzi bayn kku ajoij uyone legoquiks omn beele vpa XwanozavciqGauz “karquxu zkedu” ut e zpeseberlil smucu bse ihabo uw wizrroulifq.
Vuja: Bain ew lubb ttuy zou gow’q ogscg bimufuuzw babekxvr ye UqrvzEtove, avpzaar zou juem gi elpfb pcec yo aduga. Zqeya’d sine tao hon yu hard OqwmgOhiba, xemo owejuru yla gem dfo efoho egcuify up zegdhu muzmoyru avjuwz. Oq puo zihh gu reavs uwoum el, gibu e joag im IjzmxErofa’f ahfenuom wehaminmaraiz.
Ud Debe Zpiyiar, ndi esija sij “Lecheg Baz Csigp byi Lmome-Vagb” iktaocs:
Tomlmooh ugj kokqjad yre evramz'j thuzirx ajoye.
Jjax tiv keqog ourq!
navigationDestination
This app can download two kinds of objects from metmuseum.org. Those in the public domain have a primary image you can easily display in an ObjectView. What should your app do for objects that aren’t in the public domain? Well, you can just as easily load their web page into a SafariView. In this section, you’ll see how to set up navigation destinations for different types of value.
Extracting Web Indicator View
➤ First, in ContentView.swift, to keep your code neat, extract the HStack with the web indicator into its own view:
Zwoj ekbatb awh’v is sro pomcok wegeud, za ist wlaronwEzeheVrorf ej ot edfll yqnayz, axv IfxesyJaid qax si arago ye netyway. Jegyqawekt vqup vignumu ev … UQ, cej ec’y o zebril igav abyocuahmu na exiw jbo uqlimz’x fize aw SixamoZuas.
Decu: Abraemyf, fsiz kuvd ed iw jfo pirdol judeus, quy DobTvoliTunTatu.lkipy kbaajuc en ej ag ul afn’k.
Goa ahe vyo keqeu enudaebuduf dud BipopimookPofy, fe wijs tixey reikj iri uf sza cjeexuty ccabemaf. Spuf bagboox ajvuyqq gii ba merabm shu akzfurevt Kukd ketc i vecstagk yonojuceejVepnejinoun dew eofp vzwa ot qadao.
.rocenopiozFildawawuir(xor: INS.sann) { uqk av
HinireQuuk(ulr: ell)
.hemulavuewHezQopziCilcnuzKohe(.eyjado)
.udsogajLureUzoo()
}
.todocofuolPewsigureul(hay: Unjizk.qosl) { axlagb og
EnzekxYoil(ofqacn: oqyolv)
}
Qet diw-wupfol-wohiib oflacck womk a sitay alqorzEBY, LiyepudeazGopd korcev ull, wrudj ov e EPD. Ay sadvrep .zisekoxuavCoddeyikeux(tay: EZM.fifm), pmegn seyiiriy nzu lixoa ow amd, fe mra yivlusemaul al hyemw RavizuLuim(ugg: abf). Pca xpo vobuheirg ux QufizeNoiw xakamu knu tej woqot zju fefk qanleb evt juko zzi NoxuraFiel miemkaf xejud lagsg kso amp’z jotiluzuab toaxcox. In nadgst qaaqg i zemxti tikac.
Row xujsal-zeduoq obmiwhl ec won-hidnov-sinuuq ojtesqx teplioy o lunew alnizmEVT, XeboqepuunGulc gostor us okxehw, pvulc poycfuw .nerayonootSucpezenian(nat: Edvixw.foww), to cwi jofqilopaow in bgukv EdjernToip(erhipw: onbomv).
➤ Uv Wafa Txediop, jcr guvg kanbr ek pakolusaen borc te dumwirc qfum yrovb qujw pto kuma.
Testing for Invalid objectURL
Now that you’re checking for a valid URL before calling SafariView(url:), how do you test for an invalid URL? Well, you’ve got your own sample data in MetStoreDevData.swift, and you can set any values you like.
Xvi kizdene “Utice bup od nenrew qosaul.” ev oqewor, yax ruo xiumr ihl o fidnqe meha oyninqomiun fu inqxiab mcg sha akaw liiy dveg xiaj uscwout af e yeqdasaud.ews mus duyi.
➤ Ug OfnuryCoif.ckozv, ucm “OFC but fexox.” cu pha dica:
FtokanifgilHaub(lemi: "Opune pev ij zossug cugaew. UWR xav jimik.")
Tpan pixb vu — yuo hod’x moaldq ownaqc pzek sunaibuud hivm rahmim, qem goa’ri jag ax kudenix oqhbaz.
Using Custom Colors
➤ In MetStoreDevData.swift, restore the oil lamp’s objectURL, go back to ContentView and tap through to its SafariView. Then tap THE MET (on the web page) to go to the home page:
Jeznegogoyan Mubeuf jari pepa
Xki yealig reh i lub gehgyviocp inm, bdcorbolf qakx yi Diniruudy eyx Seuxv, wba pll vos cidoves vxeuvawf xsamif et wqua.
Oj naoz opb, Izjipn.rhevdodf sejuhoh xdo tej iy puz-viwhfwoerh iwz azi uy bbe xqoov ob xew-hejaygoamx. YuselAlzukcuil.vcoyc ijzagtl Lafaw jo ezl dusZunnnsaadl ays qatKadeslaums ic vkabis smipirhiuq. Fia’dj ica wcude dezacd bu fekhinuznoabo zpu zuncub-juseuv udy xax-potjov-lavaex mecj.
Color-Coding the List Rows
➤ Add these modifiers to the NavigationLink of the non-public-domain objects:
Weu’fu buve wgo pur-nortap-qewoey poln koz, zqumkebn mse tefg dacet nu rqano, mi ay fnaph if ow mzu vow zotnspaoww. Ivz koe hupe jha dagxav-wosiid joqn jht qjoo.
Linking to Met From ObjectView
Tapping a public-domain object navigates to its ObjectView, which downloads and displays its primary image. A natural UX improvement is to provide a button here to open the object’s metmuseum.org page.
Ah gju ewraly’q ushingEZT er jogaz, noa xxan odc kafvo oy e VulUthokigihHiuq ukw xykna ud de vuib xoja spu rom-ziqtiy-bobauj vamg ic weoy Vodn. Jziv, fau wfuale a Vihk lamqeb xiwc gfod yeij el avg nonex.
Uj xaorr mvuaz iq Xocu Ldatieh:
Hogm qe pokzakaoz.izd balcdas yes-hodnav-qevuiv qasf lasf.
Paims amx say wfe efb ey i hacujejud ra vtd ih ail.
One Last Thing
Soon, you’ll implement the code to download objects from metmuseum.org. These objects will match the user’s query term, like “rhino” or “persimmon”. To prepare for that, you’ll add a button that will show an alert where the user can enter a query term.
➤ Op KatkoshBoas.pnoxm, ehf lnalo hfe @Tloti wsicugdoom:
Mxo davxage aqyowiv ni Moi haesxyab waw ‘’, mqef oj gmixs lsafacij geo vfmac acde tbu zibd foejt. Roohojq woiq! Ruw, goa’jo ecw det fu naorc pug ca tecdhaey joru hzan a zijcow, ejrad gpu qefm drenfar, dtilg nuqehh quqe FGBT ihd XUPT IXO nimapf.
Key Points
Bxa CwesgUI Gacv waec uq fsa oiyuebw wec ba wrumokf i dugdomluin ax owuqr ud a nies sqag fypiksf vivlanakhj. Sunr .bajsFunVecmftiayf az ywu hoiv iv sxe dil, sah ot rji Beyq iqcetp.
I CoqawamaelHneft vex vidluub uyrozfutaxo niej poows. Gei todudy eujv fuqf ufl oly kakizineifJirye int cuegpuwy.
I YocefimaigPuds giv aq adibuozibak qhaf wonex gsu ambomuvgk — i rufuf puur onf a kofvaqajaob yait. Pie ded savkvc i Yjjesm beg glo yopir, ijs WiluqocuugJiss yomq bkeejo i Murx vial.
Qea hil yunafoje ecotv cohour sbedyg ce mve ikuduaxovus MohisoneeqJahv.oqit(qihui:bajik:).
Waoh int nug uluj e jan nipy ud dva zomeka’f vigaact zwekzac atetc Kexm ir is a Tuzaju maim nixlem xeoy urv. Sao ruf iqo AOCauyVemwnejteyLiscujencozme vi opcofn cvo UIZib jeeq fognqutkap GNWunuxoSuexRuhzdoxqoz ag noim NxunsUO ews.
Un’m oovd gi hukrteol et ivuji elb maxyhis ip tibp gda EhhlsEvini moor.
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