无法使用切换行为来触发SWIFTUI中的.buttonStyle

Posted 2023-01-09

我有两个buttonStyle，mainButtonOn和mainButtonOff。我希望我的按钮根据其切换状态使用一个按钮。以下代码引发错误“无法推断复杂的闭包返回类型；明确添加类型以消除歧义。”

我是SwiftUI的新手，因此，如果您愚蠢地回答问题，那么如果您能看到问题，我会很乐意。谢谢大家。

import SwiftUI
struct ContentView: View 
    var displayTime = "Ahoy"

    func getTime(oldTime: Int, addedTime: Int) -> Int 
        return oldTime + addedTime
    

       @State var hoursOn:Bool = true

    struct mainButtonOff: ButtonStyle 

        func makeBody(configuration: Self.Configuration) -> some View 
            configuration.label
                .frame(width: 110, height: 35, alignment: .center)
                .background(Color.white)
                .foregroundColor(Color.gray)
                .cornerRadius(30)
                .overlay(RoundedRectangle(cornerRadius: 30) .stroke(Color.gray, lineWidth: 1))
        
    

    struct mainButtonOn: ButtonStyle 

        func makeBody(configuration: Self.Configuration) -> some View 
            configuration.label
                .frame(width: 110, height: 35, alignment: .center)
                .background(Color.blue)
                .foregroundColor(Color.white)
                .cornerRadius(30)
                .overlay(RoundedRectangle(cornerRadius: 30) .stroke(Color.blue, lineWidth: 1))
        
    


    var body: some View 

        let displayTime = String(getTime(oldTime: 15, addedTime: 10)) // get time and turn it into a string

        return VStack  // ***** ERROR: Unable to infer complex closure return type; add explicitly type to disambiguate.
            //Spacer()
            Text(displayTime)
            //Spacer()
            Button(action: self.hoursOn.toggle()) 
                Text("Hours")
                    .font(.headline)
            
                .buttonStyle(self.hoursOn ? mainButtonOn() : mainButtonOff())
                //.buttonStyle(mainButtonOff()) // <= USING THIS LINE INSTEAD THROWS NO ERROR
        
    

答案

一种方法是绕过问题：

            if self.hoursOn 
            Button(action: self.hoursOn.toggle()) 
                Text("Hours").font(.headline)
            .buttonStyle(mainButtonOn())
         else 
            Button(action: self.hoursOn.toggle()) 
                Text("Hours").font(.headline)
            .buttonStyle(mainButtonOff())
        

另一个更简洁的方法是这样：

struct mainButtonOnOff: ButtonStyle 
    let onoff: Bool

    init(_ switsh: Bool) 
        self.onoff = switsh
    

    func makeBody(configuration: Self.Configuration) -> some View 
        configuration.label
            .frame(width: 110, height: 35, alignment: .center)
            .background(self.onoff ? Color.blue : Color.white)
            .foregroundColor(self.onoff ? Color.white : Color.gray)
            .cornerRadius(30)
            .overlay(RoundedRectangle(cornerRadius: 30) .stroke(self.onoff ? Color.blue : Color.gray, lineWidth: 1))
    


and:

    Button(action: self.hoursOn.toggle()) 
            Text("Hours") .font(.headline)
        .buttonStyle(mainButtonOnOff(self.hoursOn))