delete/add item

➖

📗 參考：Swift Playgrounds (Keep Going with Apps) - Sharing Data Between Views.

struct ContentView: View {
    
    // inject data from environment
    @EnvironmentObject var data : CreatureZoo

    var body: some View {
        SPCAssessableGroup(view: self) {
            List {
                // ...
                
                // injected data
                ForEach(data.creatures) { creature in 
                    CreatureRow(creature: creature)
                }
                // ⭐️ action to delete data item ---------------
                .onDelete { indexSet in 
                    data.creatures.remove(atOffsets: indexSet)
                }
                // ---------------------------------------------
            }
        }
    }
}

➕

📁 ContentView

struct ContentView: View {
    
    // inject data from environment
    @EnvironmentObject var data : CreatureZoo

    var body: some View {
        SPCAssessableGroup(view: self) {
            List {
                // ...
                
                // injected data
                ForEach(data.creatures) { creature in 
                    CreatureRow(creature: creature)
                }
            }
            // ⭐️ 1. UI to add new data item
            .toolbar { 
                ToolbarItem { 
                    NavigationLink("+") { 
                        // ⭐️ 2. new data item editor view
                        CreatureEditor()
                            .navigationTitle("+ Creature")
                    }
                }
            }
            
        }
    }
}

📁 CreatureEditor

// ⭐️ new data item editor view
struct CreatureEditor: View {
    
    // ⭐️ 1. data to be updated
    @EnvironmentObject var data: CreatureZoo
    
    // ⭐️ 2. new data item to be added
    @State private var creature = Creature(name: "untitled", emoji: "❓")
    
    // ⭐️ 3. 用於關閉此 view 的環境值
    @Environment(\.dismiss) private var dismiss
    
    var body: some View {
        SPCAssessableGroup(view: self) {
            
            VStack(alignment: .leading) {
                // ⭐️ 4. UI to update data item
                Form {
                    Section("Name") {
                        TextField("name", text: $creature.name)
                    }   
                    Section("Emoji") {
                        TextField("emoji", text: $creature.emoji)
                    }
                    Section("Creature Preview") {
                        CreatureRow(creature: creature)
                    }
                }
            }
            // ⭐️ 5. UI to add new data item
            .toolbar { 
                ToolbarItem { 
                    Button("Add") { 
                        // ⭐️ 6. action to add data item
                        data.creatures.append(creature)
                        // ⭐️ 7. dismiss this view
                        dismiss()
                    }
                }
            }
            
        }
    }
}

✏️

//

📘 手冊

• SwiftUI ⟩

  • Collection Containers ⟩

    • DynamicViewContent (protocol)

    • ForEach ⟩ DynamicViewContent Implementations

      • onDelete(perform:)

  • State and Data Flow ⟩

    • EnvironmentValues ⟩ dismiss -> DismissAction

  • App Structure and Behavior ⟩

    • DismissAction (struct) - defines a callAsFunction() method

• SwiftOnTap ⟩

  • DynamicViewContent ⟩ onDelete(perform:) -> some DynamicViewContent

  • View ⟩ toolbar(content:)

📗 參考

• Swift Playgrounds 4.1 (Keep Going with Apps) - Sharing Data Between Views.