如何在 swift ui 中显示两个警报，一个接着一个

Posted 2023-02-24

【中文标题】如何在 swift ui 中显示两个警报，一个接着一个

【英文标题】：How to show two alerts in swift ui one followed by the other

【发布时间】：2020-03-07 22:57:16

【问题描述】：

我想制作一个用户按下一个按钮的应用程序，然后，当他们选择一个选项时，会弹出另一个警报。当我尝试类似的事情时；

struct ContentView: View 
@State private var showingAlert = false
@State private var showingAlertII = false

var body: some View 
        Button(action: 
            self.showingAlert = true
        , label: 
            Text("button")
                .alert(isPresented: $showingAlert) 
                    Alert(title: Text("Option one or two"), message: Text("choose"), primaryButton: .default(Text("one"), action: 

        // do some specific actions
                        self.showingAlertII = true
                    ), secondaryButton: .default(Text("two"), action: 
                       //do some other stuff
                        self.showingAlertII = true
                    ))

            
            .alert(isPresented: $showingAlertII) 
                    Alert(title: Text("Option A or B"), message: Text("choose"), primaryButton: .default(Text("Split"), action: 
                        // do something
                    ), secondaryButton: .default(Text("B"), action: 
                        //do something 
                    ))

            
        )

没有显示警报。请注意，还有另一个教程：How can I have two alerts on one view in SwiftUI? 与此类似，但是，使用 .first 表示法并返回一个或另一个对我不起作用，因为我希望两个都显示，一个接一个。

【参考方案1】：

您不能在不覆盖其中一个的情况下直接在彼此后面进行两个 .alert 调用。关键是在单个 .alert 调用中获取所有逻辑。

import SwiftUI

enum ActiveAlert 
    case first, second, third


struct ContentView: View 
    @State private var showingAlert = false
    @State private var activeAlert: ActiveAlert = .first

    var body: some View 
        Button(action: 
            self.showAlert(.first)
        , label: 
            Text("button")
            .alert(isPresented: $showingAlert) 
                switch activeAlert 
                    case .first:
                        return Alert(title: Text("First Alert"), dismissButton: .default(Text("Next"), action: 
                            self.showAlert(.second)
                        ))
                    case .second:
                        return Alert(title: Text("Second Alert"), dismissButton: .default(Text("Next"), action: 
                            self.showAlert(.third)
                        ))
                    case .third:
                        return Alert(title: Text("Third Alert"), dismissButton: .default(Text("Ok"), action: 
                            //...
                        ))
                
            
        )
    

    func showAlert(_ active: ActiveAlert) -> Void 
        DispatchQueue.global().async 
            self.activeAlert = active
            self.showingAlert = true