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swiftui - 在继续之前等待 actionSheet 结果？

问题描述

我在 a 中有一个按钮.contextMenu（即：标记为已付款）

它做的第一件事是在 actionSheet 上切换以选择付款方式。紧接着是一些代码，通过 EventKit 向用户日历添加条目。

我的问题是我希望 actionSheet在 EventKit 代码执行之前返回一个结果。

你如何让它等待？

特性：

@State private var showPaymentSheet = false
@State private var paymentType = ""

var actionSheet: ActionSheet {
    ActionSheet(title: Text("Payment Method"), buttons: [
        .default(Text(" Cash")) { paymentType = " Cash" },
        .default(Text(" Bank Transfer")) { paymentType = " Bank" },
        .default(Text("️ PayPal")) { paymentType = "️ PayPal" },
        .default(Text(" Cheque")) { paymentType = " Cheque" },
        .cancel()
    ])
}

身体：

.contextMenu {

Button(action: {
    
**// Run This ActionSheet FIRST and get result of \(paymentType) **

    self.showPaymentSheet.toggle()

**// ONLY then continue with below **
   
    let thisDay = self.selectDate.selectedDate
    let eventStore = EventsRepository.shared.eventStore
    let payment = EKEvent(eventStore: eventStore)
    payment.calendar = event.calendar
    payment.startDate = event.startDate
    payment.endDate = event.endDate
    payment.title = "\(event.title!)"
    payment.notes = "\(event.notes!)\nPaid: \(Date().dateType(dateFormat: "EEE MMM dd yyyy @ HH:mm b " )) by \(paymentType)"
    payment.location = "\(event.location!)"

    do {
        try eventStore.save(payment, span: .thisEvent)//i - Save Updated (event)
        try EventsRepository.shared.eventStore.remove(event, span: .thisEvent)
        EventsRepository.shared.loadAndUpdateEvents(selectedDate: thisDay)

    }   catch {
        print("Failled to cancel event")
    }
    NotificationCenter.default.post(name: .eventsDidChange, object: nil)
}){
    HStack {
        Text("Mark as Paid")
            .font(Font.custom("ChalkboardSE-Bold", size: 32))
        Image("payment")
            .renderingMode(.original)
    }
}.actionSheet(isPresented: $showPaymentSheet, content: {
                self.actionSheet})
}

标签： swiftui

解决方案

您可以使用onReceive.

这是一个简单的演示：

struct ContentView: View {
    @State private var showPaymentSheet = false
    @State private var paymentType = ""

    var body: some View {
        Button("Choose payment") {
            self.showPaymentSheet.toggle()
        }
        .actionSheet(isPresented: $showPaymentSheet) {
            self.actionSheet
        }
        .onReceive(Just(paymentType)) { // <- add here
            guard !$0.isEmpty else { return }
            self.someOtherFunc()
        }
    }

    var actionSheet: ActionSheet {
        ...
    }

    func someOtherFunc() {
        print(paymentType)
    }
}

但是，我建议将逻辑移至单独的类并保持 View clean。还有为什么paymentType = ""？如果无法设置，您可能应该使用它nil。为什么你首先需要它是可观察的？您还可以为付款类型创建单独的枚举。

通过以上修改，我们可以编写一个更新的示例：

enum PaymentType: String {
    case cash = " Cash"
    case bank = " Bank Transfer"
    ...
}

class PaymentHandler: ObservableObject {
    func pay(_ paymentType: PaymentType) {
        // print(paymentType.rawValue) // do something with `paymentType`
    }
}

struct ContentView: View {
    @ObservedObject private var vm = ViewModel()
    @State private var showPaymentSheet = false

    var body: some View {
        Button("Choose payment") {
            self.showPaymentSheet.toggle()
        }
        .actionSheet(isPresented: $showPaymentSheet) {
            self.actionSheet
        }
    }

    var actionSheet: ActionSheet {
        ActionSheet(title: Text("Payment Method"), buttons: [
            .default(Text(PaymentType.cash.rawValue)) { self.vm.pay(.cash) },
            .default(Text(PaymentType.bank.rawValue)) { self.vm.pay(.bank) },
            .cancel(),
        ])
    }
}

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