如何让 SwiftUI 中的选择器输出选择的值？

Posted 2023-02-24

【中文标题】如何让 SwiftUI 中的选择器输出选择的值？

【英文标题】：How to get the picker in SwiftUI to output the chosen value?

【发布时间】：2020-02-11 08:47:20

【问题描述】：

我在 swiftUI 中有一个选择器，用于显示度量单位并在它们之间进行转换。选择器显示正确，但选择其中之一时未选择值。

import SwiftUI

struct ContentView: View 
    
    @State private var originalValue  = ""
    @State private var originalUnit = ""
    @State private var convertedUnit = ""
    
    let lenghtUnits = ["meters", "miles", "yards"]
    
    var convertedValue : Double 
      return 0 // for now..
    
    
    var body: some View 
        NavigationView 
            Form 
                Section(header: Text("From:")) 
                    
                    TextField("Value:", text: $originalValue)
                        .keyboardType(.decimalPad)
                    
                    Picker("fromUnit" , selection: $originalUnit) 
                        ForEach(0 ..< lenghtUnits.count) 
                            Text("\(self.lenghtUnits[$0])")
                        
                    
                    .pickerStyle(SegmentedPickerStyle())
                
                                
                Section(header: Text("Result")) 
                    Text("\(convertedValue)")
                
                
            
        .navigationBarTitle("Convert It")
        
    

【参考方案1】：

试试这个。 （在您的文本中添加标签并使您的选择值成为 int）

struct ContentView: View 

@State private var originalValue  = ""
@State private var originalUnit = 0
@State private var convertedUnit = ""

let lenghtUnits = ["meters", "miles", "yards"]

var convertedValue : Double 
  return 0 // for now..


var body: some View 
    NavigationView 
        Form 
            Section(header: Text("From:")) 

                TextField("Value:", text: $originalValue)
                    .keyboardType(.decimalPad)

                Picker("fromUnit" , selection: $originalUnit) 
                    ForEach(0 ..< lenghtUnits.count)  index in
                        Text("\(self.lenghtUnits[index])").tag(index)
                    
                
                .pickerStyle(SegmentedPickerStyle())
            

            Section(header: Text("Result")) 
                Text("\(convertedValue)")
            

        
    .navigationBarTitle("Convert It")