Swift UI Simulator Crash on Xcode

Question

Created May ’21

Replies 4

Boosts 0

Views 1.2k

Participants 2

Hi everyone,

I'm building my first project on Xcode using SwiftUI. While working on a screen that lets people enter the names of players. Additionally, it should and open a popup sheet that lets them delete certain players. While doing this I encountered a strange error. The Preview seems to crash every time I try to delete an entry in the list.

Does anyone have an idea how I could get the following code to work?

Thanks very much, any help is highly appreciated.

Code Block SwiftUI
import SwiftUI
struct Test_17_05_1: View {
   
  @State var pName: [String] = [""]
  @State var playerEnterCount: Int = 0
  @State var showPlayerlist: Bool = false
   
  func delete(at offsets: IndexSet) {
          pName.remove(atOffsets: offsets)
  }
   
  var body: some View {
    
    NavigationView {
       
    VStack {
      Spacer()
      
      HStack {
       
        Image (systemName: "person.fill")
          .foregroundColor(.secondary)
        Text("What's the name of player " + 
        String(playerEnterCount+1) + "?") 
        Spacer ()
      }
       
      HStack {
         
        Image (systemName: "person.fill.badge.plus")
          .foregroundColor(.secondary)
          
      
      }
     
      Spacer()
       
      Button("next player") {
         
        playerEnterCount += 1
         
        pName.append("")
         
      }
      .foregroundColor(.secondary)
      
            
      Spacer()
    }
     
    .navigationBarItems(trailing:
                Button(action: {
                  showPlayerlist.toggle()
                    },
                    label: {
                    Image(systemName: "person.3.fill")
                    Text("Players")
                    }).foregroundColor(.secondary)
    )
    .sheet(isPresented: $showPlayerlist, content: {
       
        List {ForEach(pName, id: \.self) {pName in
          Text(pName)
        }.onDelete(perform: delete)
        }
         
    })
       
    }
     
  }
   
}

Boost

Answer 1

Claude31 OP

May ’21

I don't understand how your code is supposed to work. How do you enter players ?
And you just append empty names…
And why do you initialise with an empty string and not just empty array ?
@State var pName: [String] = [] // [""]

So I changed for:

Code Block                 Button("next player") {
                    playerEnterCount += 1
                    pName.append("\(playerEnterCount)")
                }

I deleted names in the sheet, without crash (I could do it with blank names as well, and no crash either).

I tested both in simulator and in Preview. Same result.

So please explain your use case scenario.

0

Answer 2

LG1 OP

May ’21

Thank you Claude for your help

There should have been the following code in line 35 which somehow I must have accidentally deleted in this post.

Code Block TextField("...", text: $pName[playerEnterCount])

This would've been the text field that allowed players to change the empty entries to their actual names. This is also what makes the simulator crash. So I know that this is the problem that I don't know an answer to yet...

All this is part of the first view of an app that lets people enter their names to play a "truth or dare" game in the next view.

0

Answer 3

Claude31 OP

May ’21

Accepted Answer

When you perform ondelete, you need to decrement playerEnterCount.

Code Block     func delete(at offsets: IndexSet) {
        pName.remove(atOffsets: offsets)
        playerEnterCount -= 1
    }

At the end of the List, you have an empty name.
So, you could filter the list :

Code Block                 List {
                    ForEach(pName.filter() {$0 != "" }, id: \.self)  { aName in
                         Text(aName)
                    }.onDelete(perform: delete)
                }

1

Answer 4

LG1 OP

May ’21

Thanks, this works brilliantly!

0