我的ObservableObject类数组变量'timeStep‘无法保存值

Question

我有两个ObservableObject类: CarLotData和StopWatchManager。我想要做的是使用我的StopWatchManager类加载CarLotData属性timeStep--这是一个数组双类型。

下面是我的StopWatchManager代码：

import Foundation
import SwiftUI

class StopWatchManager: ObservableObject {
    
@ObservedObject var carLotData = CarLotData()

var timer = Timer()
    
@Published var mode: stopWatchMode = .stopped
@Published var secondsElapsed = 0.0
  
enum stopWatchMode {
case running
case stopped
case paused
}
    
func start() {

            
mode = .running
timer = Timer.scheduledTimer(withTimeInterval: 0.1, repeats: true) { timer in
self.secondsElapsed = self.secondsElapsed + 0.1
}
        
}
func stop() {
        
          
timer.invalidate()
          
        
if carLotData.timeStep.count < 7 {
carLotData.timeStep.append(secondsElapsed)
print(carLotData.timeStep)
mode = .stopped
           
}
          
          
}
         
}

下面是我的CarLotData代码：

import SwiftUI
import Foundation

class CarLotData: ObservableObject {


@Published var carLotData: Int = 0

@Published var carStep: [Double] = []




var id = UUID()
var newUsed: Int = 0
var powerType: Int = 0
var downPayment: Int = 0
var salesmanType: Int = 0
var appointment: Int = 0
var internet: Int = 0
var retail: Int = 0
var carType: Int = 0
var carBrand:  Int = 0
var purchaseType: Int = 0
var creditRank: Int = 0
var warranty: Int = 0
var service: Int = 0
var thirdParty: Int = 0
var timeStep: [Double] = []
var salesman: Int = 0   
}

最后，这里是我的观点，在这里我得到了"timeStep = []“，其中我想要一个双值数组。

import SwiftUI

struct CarLotDataView: View {

@ObservedObject var carLotData = CarLotData()
@ObservedObject var stopWachManager = StopWatchManager()

var body: some View {
    
    
List {

Group {


Text("Customer ID: \(carLotData.id)")
Text("Salesman: \(carLotData.salesman)")
Text("New/Used: \(carLotData.newUsed)")
Text("Power Type: \(carLotData.powerType)")
Text("Down Payment: \(carLotData.downPayment)")
Text("Salesman Type: \(carLotData.salesmanType)")
Text("Appointment: \(carLotData.appointment)")
}

Group {

Text("Internet: \(carLotData.internet)")
Text("Retail: \(carLotData.retail)")
Text("Car Type: \(carLotData.carType)")
Text("Car Brand: \(carLotData.carBrand)")
Text("Purchase Type: \(carLotData.purchaseType)")
Text("Credit Rankd: \(carLotData.creditRank)")
Text("Warranty: \(carLotData.warranty)")
Text("Service: \(carLotData.service)")
Text("Third Party: \(carLotData.thirdParty)")
Text("Time Steps: \(carLotData.timeStep)" as String)

}

}
    
}
}

其他一切都正常，只是计时器的值没有被传输到我的timeStep数组中。任何见解都将不胜感激。

Answer 1

您正在尝试从StopWatchManager访问和更新CarLotData，并且正在使用，但是在您的视图中使用的完全是另一个，您必须使用与您更新的相同的一个！

技巧总是使用您启动的相同的引用！

将这一行添加到CarLotData中

static let shared: CarLotData = CarLotData()

然后在StopWatchManager上使用这段代码

let carLotData = CarLotData.shared

不要在类中使用@观察站对象，只需使用let，它就可以完成任务。

最后，在您的视图中使用这个：

@ObservedObject var carLotData = CarLotData.shared

对于我的个人应用程序，我会使用下面的代码：

@StateObject var carLotData = CarLotData.shared

Answer 2

您要创建两次CarLotData。正确的方法是确保访问正确的引用。

另一种方法是使CarLotData成为单例。但是，如果您要在多个视图中使用这些数据，这才是正确的方法。

class CarLotData: ObservableObject {
  static public let shared = CarLotData()
  private init() { }
}

那你就会像这样使用它。确保永远不要调用CarLotData()

Text("Internet: \(CarLotData.shared.internet)")