SwiftData 共享数据库在 App 中的改变无法被 Widgets 感知的缘故原由和办理 - ToB企服应用市场:ToB评测及商务社交产业平台

import Foundation
import SwiftData
@Model
class Hero {
var hid: UUID
var name: String
var power: Int
var residentCount: Int = 0
var timestamp: Date
init(name: String, power: Int) {
self.hid = UUID()
self.name = name
self.power = power
timestamp = .now
}
func update() {
timestamp = .now
}
private static let HeroInfos: [(name: String, power: Int)] = [
("黑悟空", 10000),
("钢铁侠", 5000),
("灭霸他爸", 500000),
]
@MainActor
static func spawnHeros(forPreview: Bool = true) {
let container = forPreview ? ModelContainer.preview : .shared
let context = container.mainContext
if !forPreview {
let desc = FetchDescriptor<Hero>()
if try! context.fetchCount(desc) > 0 {
return
}
}
for hero in HeroInfos {
let new = Hero(name: hero.name, power: hero.power)
context.insert(new)
}
try! context.save()
}
}
@Model
class Model {
private static let UniqID = UUID(uuidString: "3788ABA9-043C-4D34-B119-5D69D486CBBA")!
var mid: UUID
@Relationship(deleteRule: .nullify)
var residentHero: Hero?
init(mid: UUID) {
self.mid = mid
self.residentHero = nil
}
@MainActor
static var shared: Model = {
let context = ModelContainer.auto.mainContext
let predicate = #Predicate<Model> { model in
model.mid == UniqID
}
let desc = FetchDescriptor(predicate: predicate)
if let result = try! context.fetch(desc).first {
return result
} else {
let new = Model(mid: UniqID)
context.insert(new)
try! context.save()
return new
}
}()
// 随机产生驻场英雄
@MainActor
func chooseResidentHero() {
let context = ModelContainer.auto.mainContext
let desc = FetchDescriptor<Hero>(sortBy: [.init(\Hero.power)])
if let hero = try! context.fetch(desc).randomElement() {
residentHero = hero
hero.residentCount += 1
try! context.save()
}
}
}

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struct ContentView: View {
@Environment(\.scenePhase) var scenePhase
@Environment(\.modelContext) var modelContext
var body: some View {
NavigationStack {
Group {
// 具体实现从略...
}
.navigationTitle("英雄集合")
}
.onChange(of: scenePhase) {_, new in
if new == .inactive {
Model.shared.chooseResidentHero() // 1
WidgetCenter.shared.reloadAllTimelines() // 2
}
}
}
}

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struct IncValueWidgetEntryView : View {
var entry: Provider.Entry
var body: some View {
VStack {
if let residentHero = Model.shared.residentHero {
VStack(alignment: .leading) {
HStack {
Label(residentHero.name, systemImage: "person.and.background.dotted")
.foregroundStyle(.red)
.minimumScaleFactor(0.5)
Spacer()
Text("已驻场 \(residentHero.residentCount) 次")
.font(.system(size: 12))
.foregroundStyle(.secondary)
}
HStack {
Text("战斗力 \(residentHero.power)")
.minimumScaleFactor(0.5)
Spacer()
Button(intent: EnhancePowerIntent()) {
Image(systemName: "bolt.ring.closed")
}
.tint(.green)
}
}
} else {
ContentUnavailableView("英雄都放假了...", systemImage: "xmark.seal")
}
}
.fontWeight(.heavy)
}
}

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@MainActor
static var shared: Model = {
let context = ModelContainer.auto.mainContext
let predicate = #Predicate<Model> { model in
model.mid == UniqID
}
let desc = FetchDescriptor(predicate: predicate)
if let result = try! context.fetch(desc).first {
return result
} else {
let new = Model(mid: UniqID)
context.insert(new)
try! context.save()
return new
}
}()

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@MainActor
static var liveShared: Model {
let context = ModelContainer.auto.mainContext
let predicate = #Predicate<Model> { model in
model.mid == UniqID
}
let desc = FetchDescriptor(predicate: predicate)
if let result = try! context.fetch(desc).first {
return result
} else {
let new = Model(mid: UniqID)
context.insert(new)
try! context.save()
return new
}
}

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struct IncValueWidgetEntryView : View {
var entry: Provider.Entry
var body: some View {
VStack {
if let residentHero = Model.liveShared.residentHero {
// 原代码从略...
} else {
ContentUnavailableView("英雄都放假了...", systemImage: "xmark.seal")
}
}
.fontWeight(.heavy)
}
}

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