Sphere's questions

我的应用程序的核心部分是一个计时器。到目前为止，这是代码（从主代码库中取出，以尽量减少可重现性）：

import SwiftUI

struct TestView: View {

    @State var countdownTimer = 5 * 60      /// The actual seconds of the timer, being counted down/up
    @State var timerRunning = false         /// Var to set and see if timer is running
    
    var body: some View {
        /// For formatting the timer numbers
        let style = Duration.TimeFormatStyle(pattern: .minuteSecond)
        let formTimer = Duration.seconds(countdownTimer).formatted()
        let formTimerShort = Duration.seconds(countdownTimer).formatted(style)
        
        /// The main Timer If there are no hours we hide the hour number and make the timer bigger in this way.
        Text(countdownTimer / 3600 == 0 && timerRunning ? "\(formTimerShort)" : "\(formTimer)")
            .onReceive(Timer.publish(every: 1, on: .main, in: .common).autoconnect()) { _ in
                    if countdownTimer > 0 && timerRunning {
                        countdownTimer -= 1
                    } else {
                        timerRunning = false
                    }
            }
        
        /// The Start and Pause buttons
        HStack {
            if !timerRunning {
                Button(action: {
                    timerRunning = true
                }) {
                    Text("Start")
                        .frame(width: 300, height: 75)
                        .font(.system(size: 60))
                }
            } else {
                Button(action: {
                    timerRunning = false
                }) {
                    Text("Pause")
                        .frame(width: 300, height: 75)
                        .font(.system(size: 60))
                }
            }
        }
    }
}

#Preview {
    TestView()
}

问题在于它不准确。1 小时的计时器使用时间大约为 40 秒。所以我的想法是将计时器的发布时间从 1 改为 0.001，从而提高分辨率。此代码有效，但准确性更低！

struct TestView: View {

    @State var countdownTimer = 5 * 60      /// The actual seconds of the timer, being counted down/up
    @State private var fractionTimer = 0    /// Helping us to make the timer more accurate
    @State var timerRunning = false         /// Var to set and see if timer is running
    
    var body: some View {
        [...]
        
        /// The main Timer If there are no hours we hide the hour number and make the timer bigger in this way.
        Text(countdownTimer / 3600 == 0 && timerRunning ? "\(formTimerShort)" : "\(formTimer)")
            .onReceive(Timer.publish(every: 0.001, on: .main, in: .common).autoconnect()) { _ in
                /// Count up the fraction timer, only if he hits a certain Number we count up our Visible Timer
                if timerRunning {
                    fractionTimer += 1
                }
                
                if fractionTimer == 1000 {
                    if countdownTimer > 0 && timerRunning {
                        countdownTimer -= 1
                        fractionTimer = 0
                    } else {
                        timerRunning = false
                        fractionTimer = 0
                    }
                }
            }

        [...]
    }
}

根据我的逻辑，这应该将误差从每小时 40 秒降低到每小时 0.04 秒。但实际上现在误差是每小时 120 秒！

怎么会这样？是不是因为它在主线程上运行，并且每秒调用 1000 次，所以有许多其他任务会延迟该调用？我应该从主线程中获取它吗？

我有一个 SwiftData 模型，最近添加了一个新数组，该数组以字符串形式保存“Sections”。无论我尝试什么，我都无法让 Swift 使用 ForEach、For 或 List 以任何方式遍历这个数组。我总是收到此错误：

Generic parameter 'V' could not be inferred

如果我使用另一个数组 tapas.asanas，它可以完美运行。

这是代码片段，错误显示在 Section("Sections") 行。

Section("Sections") {
    TextField("Add a new Section", text: $sectionName)
        .padding([.top, .bottom], 10)
    Button(action: {
        tapas.tapasSections.append(sectionName)
        sectionName = ""
    }, label: {
        Text("Add Section")
    })
    
    List(tapas.tapasSections) { name in
        Text("\(name)")
    }
}

以下是 SwiftData 模型：

import Foundation
import SwiftData


@Model
class Tapas {
    var name: String
    
    /// Time Frame of the Tapas
    var currentDay: Int
    var lengthInDays: Int = 21
    var lastDay: Date
    var startDay: Date = Date()
    
    var intention: String
    var intentionEvoked: Bool = false
    var rules: String = ""
    var supportTime: [Date] = []
    var tapasSections: [String] = []
    
    var recuperated: Bool
    var tapasType: String
    var isActive: String
    
    var recupType: String                   /// NoRecoup, TimedRecoup, UnlimitedRecoup for No recouperations, Recouperations before Last Day, And even after
    var resetTime: Date
    
    var color: String
    
    /// Adding a relation to TapasAsana, as one Tapas has many Asanas
    @Relationship(deleteRule: .cascade) var asanas = [TapasAsana]()
    
    
    init(name: String = "", intention: String = "", currentDay: Int = 1, lengthInDays: Int = 49, lastDay: Date = .now, recuperated: Bool = false, tapasType: String = "hatha", isActive: String = "dormant", recupType: String = "NoRecoup", resetTime: Date = .now, color: String = "blue") {
        self.name = name
        self.intention = intention
        self.currentDay = currentDay
        self.lengthInDays = lengthInDays
        self.lastDay = lastDay
        self.recuperated = recuperated
        self.tapasType = tapasType
        self.isActive = isActive
        self.recupType = recupType
        self.resetTime = resetTime
        self.color = color
    }
}

正如我之前所说，这个名为 asanas 的关系数组可以在任何 ForEach 或 List 中工作，在上面的代码中也是如此。用 tapas.tapasSections 替换 tapas.tapasSections 可以解决错误。

我有一个包含一些 SwiftData 模型的应用程序。其中一个模型名为 Tapas，它与 TapasAsana 有关系。一个 Tapas 包含多个 Asana，因此我通过关系将它们关联起来。到目前为止，一切运行良好。

现在我刚刚忘记了 TapasAsana 中的一个属性。我读过关于轻量级迁移的文章，应该很容易添加该属性。但无论我在属性的末尾还是中间添加它，它都会破坏我的应用程序。应用程序编译并运行，但旧数据不再显示。在应用程序中创建新数据也行不通，尝试直接创建 TapasAsana 会导致应用程序崩溃。

这是 TapasAsana 模型的代码，我正在向其中添加一个属性。新属性称为 recoupCount。

import Foundation
import SwiftData

@Model
class TapasAsana {
    var name: String
    var duration: Int           /// How long to execute daily
    var timeToday: Int          /// Time done already today
    var recoupCount: Int      /// How many recoups this Asana has.
    
    var polar: Bool             /// If it is a polar Asana
    var doneToday: Bool         /// If it is completed today
    
    init(name: String = "Padahastasana", duration: Int = 5 * 60, timeToday: Int = 0, recoupCount: Int = 0, polar: Bool = false, doneToday: Bool = false) {
        self.name = name
        self.duration = duration
        self.timeToday = timeToday
        self.recoupCount = recoupCount
        self.polar = polar
        self.doneToday = doneToday
    }
}

我尝试只添加新属性，将其添加到最后位置，以免混淆 SwiftData 的顺序。但这些都不起作用。我没有再尝试，因为阅读有关迁移的文章说，简单地添加属性应该可以正常工作。