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Module 2: Challenge 4

So I just started on Challenge 4 of Module 2 and I am getting the following errors. Cannot find ‘action’ in scope, consecutive statements on a line must be separated by ‘;’
Insert ‘;’
Expected expression

Any Advice?

//
//  ContentView.swift
//  Shared
//
//  Created by Eric Beecroft on 10/6/21.
//

import SwiftUI

struct ContentView: View {
    var body: some View {
        VStack{
            Button("1"){ action: numberList = Integer.random(1...10)
                List(numberList in array)
            }
            
            Button("2"){ action: //Increase all numbers when tapped
                List(numberList in array ++)
                
            }
            Button("3"){action: numberList.removeAll()
                
            }
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

Your button can look like this instead of how you have it written

Button {
// action code here
} label: {
Text(“1”)
}

Change:

to:

Button("1") {
    numberList = Int.random(in: 1...10)
}
  1. Integer is not a type in Swift; Int is.
  2. What are you doing with this line: List(numberList in array)? You can’t have a List inside tha action closure of a Button and where does array come from?

Charles,

You have a number of active threads in the Code Crew community. One each for Module 2 challenges 2, 3 and 4 and a couple of others for the 14 day Challenge. I would recommend that you deal with one at a time because the understanding that you gain in one challenge has a bearing on the next.

With reference to the above code, you can’t place a List() inside a button.

The challenge says to create a UI with a List and 3 Buttons below it, so in very basic terms it should look like this:

VStack {

    List 

    Button

    Button

    Button

}

I decided to reduce the code down to a few buttons. Right now I am getting the error message that the numberList is out of scope.

//
//  ContentView.swift
//  Shared
//
//  Created by Eric Beecroft on 10/6/21.
//

import SwiftUI

struct ContentView: View {
    var body: some View {
        VStack{
            Button("1"){ numberList = Int.random(1...10)
            }
            
            Button("2"){
                
            }
            Button("3"){
                
            }
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

That is something I didn’t know, I thought that was something you can do in Swift.

Consider changing it to a let

struct ContentView: View {
    var body: some View {
        VStack{
            Button("1") { 
                let numberList = Int.random(1...10)
            }
            
            Button("2"){
                
            }
            Button("3"){
                
            }
        }
    }
}

I added the let statement and I am now getting an error message that reads “Missing argument label ‘in:’ in call”
Any advice?

//
//  ContentView.swift
//  Shared
//
//  Created by Eric Beecroft on 10/6/21.
//

import SwiftUI

struct ContentView: View {
    var body: some View {
        VStack{
            Button("1"){
                let numberList = Int.random(1...10)
            }
            
            Button("2"){
                
            }
            Button("3"){
                
            }
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

Did you try clicking on the fix it offered by Xcode? That will often correct the error for you.

In this case, Int.random(1...10) should be Int.random(in: 1...10)

1 Like

It fixed it. I looked at the answer but I don’t know how they came up with it. I am kind of struggling to understand the answer.

import SwiftUI

struct ContentView: View {
    
    // Stores our generated numbers
    @State var numbers = [Int]()
    
    var body: some View {
        
        VStack {
            
            // For each number, create a text element
            List(numbers, id: \.self) { num in
                
                Text(String(num))
            }
            HStack(spacing: 10.0) {
                Button("Generate") {
                    
                    // Declare a variable outside the scope of the loop
                    var randNumber = 0
                    
                    // Loop
                    repeat {
                        
                        // Randomize a number
                        randNumber = Int.random(in: 1...10)
                        
                        // Add it to our array
                        numbers.append(randNumber)
                        
                        // If it's not a 7, then loop
                    } while randNumber != 7
                    
                }
                .padding()
                .background(Color.blue)
                .cornerRadius(10)
                
                Button("Add +1") {
                    
                    // Check if there are items in the array
                    if numbers.count == 0 {
                        
                        // The return keyword will cause execution to stop and return (skipping all the code below the return keyword)
                        return
                    }
                    
                    // Loop through the array
                    for index in 0...numbers.count-1 {
                        
                        // Increment it by 1
                        numbers[index] += 1
                    }
                }
                .padding()
                .background(Color.blue)
                .cornerRadius(10)
                
                Button("Clear") {
                    numbers.removeAll()
                }
                .padding()
                .background(Color.blue)
                .cornerRadius(10)
            }
            .foregroundColor(.white)
            
        }
        
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

What don’t you understand?

I don’t get how they were able to add the list to the view. As from my understanding of the lesson that was something that wouldn’t have been able to be put in a VStack or HStack. How do I go from the code I have to the solution?

From this

//
//  ContentView.swift
//  Shared
//
//  Created by Eric Beecroft on 10/6/21.
//

import SwiftUI

struct ContentView: View {
    var body: some View {
        VStack{
            Button("1"){
                let numberList = Int.random(in: 1...10)
            }
            
            Button("2"){
                
            }
            Button("3"){
                
            }
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

To this

//
//  ContentView.swift
//  Module2Challenge4Solution
//
//  Created by Eric Beecroft on 10/22/21.
//

import SwiftUI

struct ContentView: View {
    @State var numbers = [Int]()
    
    var body: some View {
        VStack{
            List(numbers, id: \.self){ num in
                Text(String(num))
            }
            HStack(spacing: 10.0){
                Button("Generate"){
                    var randNumber = 0
                    repeat{
                        randNumber = Int.random(in: 1...10)
                        numbers.append(randNumber)
                    }
                    while randNumber != 7
                }.padding().background(Color.blue).cornerRadius(10)
                Button("Add +1"){
                    if numbers.count == 0{
                        return
                    }
                    for index in 0...numbers.count-1{
                        numbers[index] += 1
                    }
                }.padding().background(Color.blue).cornerRadius(10)
                Button("Clear"){
                    numbers.removeAll()
                }.padding().background(Color.blue).cornerRadius(10)
            }.foregroundColor(.white)
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}
1 Like