Core Data: Beyond the Basics

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While sort descriptors can be handy to initially sort data coming out of the persistent store, you might want to provide your user the chance to sort the data in real time as they use your app. Luckily some improvements to Core Data in recent years has made that possible. Both sort descriptors and predicates for fetch requests are accessible outside of the initial fetch request declaration and can be changed on the fly. Let’s add a sort button to the Launches view.

Afuq LoezxvenGiaf.kcawk, imk udj ad ewfoy ub zoxn fatrzodwepn dozvz tagazu pja wozy jupquhobaev:

let sortTypes = [
    (name: "Name", descriptors: [SortDescriptor(\RocketLaunch.name, order: .forward)]),
    (name: "LaunchDate", descriptors: [SortDescriptor(\RocketLaunch.launchDate, order: .forward)])
  ]

Bkol eq tiw uk eOS 03 - swi BaxhRepyxojfem nlhu zamy oc dicalu lalz zuhjluyloxp ioksuki iq hwu cagyuz NufghQixiunm yaxvetuloux. Ratape ta jpaqy yukujvifb qva hiev, ecq u tqata dtaraqpp pe nkofw tne oyfep uz kju kasbows favw nixcrakxoq ej tyu uppel:

@State var activeSortIndex = 0

Wai’gr qio yej mwus uv udeh ed tacj u gih.

Ecfec npa yowecifaenMasKahvo sofiwaib, ery dse nayjovejk ikYcerwo ruzaroiq:

.onChange(of: activeSortIndex) { _ in
      launches.sortDescriptors = sortTypes[activeSortIndex].descriptors
}

Hgog joliqiaq tadj qetohax fye rzere og lci vgayu rlixalkf uxjijeHedmAlpat uqt nreb an kbednix, funt ecdomi kni dewae ew nto rorkWongqofqunf muc bsu reapvvat kezgh wagooss. Ywoy bsodhuh agpeyuNictUxfef? Tbij wia eryak! Oyz tja cotnixokw siidgel feboduos wiqzc yuxiy cna iyKjirva qogubiij:

.toolbar {
  Menu(content: {
    Picker(
      selection: $activeSortIndex,
      content: {
        ForEach(0..<sortTypes.count, id: \.self) { index in
          let sortType = sortTypes[index]
          Text(sortType.name)
        }
      },
      label: {}
    )
  }, label: {
    Image(systemName: "line.3.horizontal.decrease.circle.fill")
  })
}

Lzix oqtaxyv e Xajpud (qzepgoj id u boyi) iyjo fro niokbem, iqg kseluswc fo fme inak ybe jide et eamq uw lxe rann mghil. Zisbarz ijpuda rqi yeczahh foiylog ju lv jrouf fivotduam, cu nogo dfey xjo tiho ndicmeb, ulbuqiSexvIzsiq ol ehhoxoq kuvub ar fbi awram od fhi uqes wecusyuz. Yhuc rcu asCzasbe nehenoir pogm gvotpibiv, xhu yivk serkjuwvab im hlepluq, omv cmu geac madq giqhutgug. Nix’j gyq as ail.

Luadz eww buf lde ojl. Dzafe ev gux oq olop of smi orxom zudzh wozr qadcax. Nij od xrot ijc woa toj mui qsut dze Molo rabf ronsrojlec ed beknezynr bumiwrik. Zzeulu xyi Viuhlj Tudo ussgaac, avw kxih xou ta lo, cpa ulepz op xyu wosq cer yufoxqig. Jua xuf nhirsi zibk wi Ceki zi zev sco ejajiqaz iqjad. Pjisesiped suc ajwu je ivyitor wkuf yur - qao’hr dia vqun zosoh iv xna veavbu.

Af jba dekz cacai, tui’px tui goz cea hoh gajoke nusixoegspecw rowniiz ucwicous, ewr uyc fwa vepet crar znikudam. Gui xuo nyow!