Ios SwiftUI-在视图模型数组中更新模型时刷新模型视图_Ios_Swift_Mvvm_Swiftui_Observable

Ios SwiftUI-在视图模型数组中更新模型时刷新模型视图

ios swift mvvm swiftui

Ios SwiftUI-在视图模型数组中更新模型时刷新模型视图,ios,swift,mvvm,swiftui,observable,Ios,Swift,Mvvm,Swiftui,Observable,问一个简单的问题，但我可能忘记了代码中的某些内容。让我们使用图像更好地解释：我基本上需要在选择/取消选择项目时更新“计数”和“价格” 我的代码结构如下：型号： class ServiceSelectorModel: Identifiable, ObservableObject { var id = UUID() var serviceName: String var price: Double init(serviceName: String

问一个简单的问题，但我可能忘记了代码中的某些内容。
让我们使用图像更好地解释：

我基本上需要在选择/取消选择项目时更新“计数”和“价格”

我的代码结构如下：

型号：

class ServiceSelectorModel: Identifiable, ObservableObject {
    var id = UUID()

    var serviceName: String
    var price: Double
    
    init(serviceName: String, price: Double) {
        self.serviceName = serviceName
        self.price = price
    }

    @Published var selected: Bool = false
}

class ServiceSelectorViewModel: ObservableObject {
    @Published var services = [ServiceSelectorModel]()

    init() {
        self.services = [
            ServiceSelectorModel(serviceName: "SERVICE 1", price: 1.80),
            ServiceSelectorModel(serviceName: "SERVICE 2", price: 10.22),
            ServiceSelectorModel(serviceName: "SERVICE 3", price: 2.55)
        ]
    }
}

视图模型：

class ServiceSelectorModel: Identifiable, ObservableObject {
    var id = UUID()

    var serviceName: String
    var price: Double
    
    init(serviceName: String, price: Double) {
        self.serviceName = serviceName
        self.price = price
    }

    @Published var selected: Bool = false
}

class ServiceSelectorViewModel: ObservableObject {
    @Published var services = [ServiceSelectorModel]()

    init() {
        self.services = [
            ServiceSelectorModel(serviceName: "SERVICE 1", price: 1.80),
            ServiceSelectorModel(serviceName: "SERVICE 2", price: 10.22),
            ServiceSelectorModel(serviceName: "SERVICE 3", price: 2.55)
        ]
    }
}

切换视图

struct ServiceToggleView: View {
    @ObservedObject var model: ServiceSelectorModel
    
    var body: some View {
        VStack(alignment: .center) {
            HStack {
                Text(model.serviceName)
                
                Toggle(isOn: $model.selected) {
                    Text(String(format: "€ +%.2f", model.price))
                        .frame(maxWidth: .infinity, alignment: .trailing)
                }
            }
            .background(model.selected ? Color.yellow : Color.clear)
        }
    }
}

struct ServiceSelectorView: View {

    @ObservedObject var serviceSelectorVM = ServiceSelectorViewModel()

    var body: some View {
        VStack {
            VStack(alignment: .leading) {
                ForEach (serviceSelectorVM.services, id: \.id) { service in
                    ServiceToggleView(model: service)
                }
            }

            let price = serviceSelectorVM.services.filter{ $0.selected }.map{ $0.price }.reduce(0, +)

            Text("SELECTED: \(serviceSelectorVM.services.filter{ $0.selected }.count)")
            Text(String(format: "TOTAL PRICE: €%.2f", price))    
        }
    }
}

服务选择或查看

struct ServiceToggleView: View {
    @ObservedObject var model: ServiceSelectorModel
    
    var body: some View {
        VStack(alignment: .center) {
            HStack {
                Text(model.serviceName)
                
                Toggle(isOn: $model.selected) {
                    Text(String(format: "€ +%.2f", model.price))
                        .frame(maxWidth: .infinity, alignment: .trailing)
                }
            }
            .background(model.selected ? Color.yellow : Color.clear)
        }
    }
}

struct ServiceSelectorView: View {

    @ObservedObject var serviceSelectorVM = ServiceSelectorViewModel()

    var body: some View {
        VStack {
            VStack(alignment: .leading) {
                ForEach (serviceSelectorVM.services, id: \.id) { service in
                    ServiceToggleView(model: service)
                }
            }

            let price = serviceSelectorVM.services.filter{ $0.selected }.map{ $0.price }.reduce(0, +)

            Text("SELECTED: \(serviceSelectorVM.services.filter{ $0.selected }.count)")
            Text(String(format: "TOTAL PRICE: €%.2f", price))    
        }
    }
}

在这段代码中，我能够更新模型的

选中状态

，但视图模型包含所有模型，并且应该刷新

价格

而不是更新
阵列中的模型似乎没有改变

我忘记了什么？

最简单的方法可能是将模型设置为值类型，然后更改其属性。持有它的视图模型将被更新。并更新视图以使用绑定到这些值

struct ServiceSelectorModel: Identifiable {
    var id = UUID()

    var serviceName: String
    var price: Double
    
    init(serviceName: String, price: Double) {
        self.serviceName = serviceName
        self.price = price
    }

    var selected: Bool = false
}

struct ServiceToggleView: View {
    @Binding var model: ServiceSelectorModel
...
}

...

ForEach (serviceSelectorVM.services.indices, id: \.self) { i in
    ServiceToggleView(model: $serviceSelectorVM.services[i])
}

注意：内联编写，未经测试，可能需要修复某些打字错误。如果您仔细注意，您已经创建了两个不同的单一真相来源。这就是父级未更新的原因，因为它未链接到子级

一种方法是将

ServiceSelectorModel

创建为结构，并在子视图中将

services

数组作为

@Binding

传递。下面是工作示例

视图模型-：

struct ServiceSelectorModel {
    
    var id = UUID().uuidString
    var serviceName: String
    var price: Double
    var isSelected:Bool = false
    
    init(serviceName: String, price: Double) {
        self.serviceName = serviceName
        self.price = price
    }
    
}

class ServiceSelectorViewModel: ObservableObject,Identifiable {
    
    @Published var services = [ServiceSelectorModel]()
    
    var id = UUID().uuidString
    init() {
        self.services = [
            ServiceSelectorModel(serviceName: "SERVICE 1", price: 1.80),
            ServiceSelectorModel(serviceName: "SERVICE 2", price: 10.22),
            ServiceSelectorModel(serviceName: "SERVICE 3", price: 2.55)
        ]
    }
}

struct ServiceToggleView: View {
    @Binding var model: [ServiceSelectorModel]
    
    var body: some View {
        VStack(alignment: .center) {
            ForEach(0..<model.count) { index in
                HStack{
                    Text(model[index].serviceName)
                    Toggle(isOn: $model[index].isSelected) {
                        Text(String(format: "€ +%.2f", model[index].price))
                            .frame(maxWidth: .infinity, alignment: .trailing)
                    }
                }.background(model[index].isSelected ? Color.yellow : Color.clear)
            }
            
        }
    }
}

struct ServiceSelectorView: View {
    
    @ObservedObject var serviceSelectorVM = ServiceSelectorViewModel()
    
    var body: some View {
        VStack {
            VStack(alignment: .leading) {
                ServiceToggleView(model: $serviceSelectorVM.services)
            }
            
            let price = serviceSelectorVM.services.filter{ $0.isSelected }.map{ $0.price }.reduce(0, +)
            
            Text("SELECTED: \(serviceSelectorVM.services.filter{ $0.isSelected }.count)")
            Text(String(format: "TOTAL PRICE: €%.2f", price))
        }
    }
}

视图-：

struct ServiceSelectorModel {
    
    var id = UUID().uuidString
    var serviceName: String
    var price: Double
    var isSelected:Bool = false
    
    init(serviceName: String, price: Double) {
        self.serviceName = serviceName
        self.price = price
    }
    
}

class ServiceSelectorViewModel: ObservableObject,Identifiable {
    
    @Published var services = [ServiceSelectorModel]()
    
    var id = UUID().uuidString
    init() {
        self.services = [
            ServiceSelectorModel(serviceName: "SERVICE 1", price: 1.80),
            ServiceSelectorModel(serviceName: "SERVICE 2", price: 10.22),
            ServiceSelectorModel(serviceName: "SERVICE 3", price: 2.55)
        ]
    }
}

struct ServiceToggleView: View {
    @Binding var model: [ServiceSelectorModel]
    
    var body: some View {
        VStack(alignment: .center) {
            ForEach(0..<model.count) { index in
                HStack{
                    Text(model[index].serviceName)
                    Toggle(isOn: $model[index].isSelected) {
                        Text(String(format: "€ +%.2f", model[index].price))
                            .frame(maxWidth: .infinity, alignment: .trailing)
                    }
                }.background(model[index].isSelected ? Color.yellow : Color.clear)
            }
            
        }
    }
}

struct ServiceSelectorView: View {
    
    @ObservedObject var serviceSelectorVM = ServiceSelectorViewModel()
    
    var body: some View {
        VStack {
            VStack(alignment: .leading) {
                ServiceToggleView(model: $serviceSelectorVM.services)
            }
            
            let price = serviceSelectorVM.services.filter{ $0.isSelected }.map{ $0.price }.reduce(0, +)
            
            Text("SELECTED: \(serviceSelectorVM.services.filter{ $0.isSelected }.count)")
            Text(String(format: "TOTAL PRICE: €%.2f", price))
        }
    }
}

struct ServiceToggleView:视图{
@绑定变量模型：[ServiceSelectorModel]
var body：一些观点{
VStack（对齐：。中心）{
ForEach（0..不要担心打字错误，我只需要一个关于如何修复的建议，而不是复制/粘贴：）