实际上，您需要一个变量来决定是否显示文本字段。当用户按下按钮时，该变量切换（到“真”或“假”）。
像这样：

import SwiftUI

struct TextFields : View {
    
    @State private var showTextFields = false
    
    @State private var textField1Input: String = "input1"
    @State private var textField2Input: String = "input2"
    @State private var textField3Input: String = "input3"

    var body: some View {
        
        VStack {
            Button("Show/Hide Textfields") {
                showTextFields.toggle()
            }
            if showTextFields {
                VStack {
                    TextField("", text: $textField1Input)
                    TextField("", text: $textField2Input)
                    TextField("", text: $textField3Input)
                }.padding()
            }
        }
        
    }
    
}

struct TextFields_Previews: PreviewProvider {
    static var previews: some View {
        TextFields()
    }
}