"SwiftUI：绑定从环境对象派生的结构的属性"

Question

I have two structs in my task manager app:

struct Task {
    var identifier: String
    var title: String
    var tags: [String] // Array of tag identifiers
}
struct Tag {
    var identifier: String
    var title: String
}

Answer 1

No, you're not necessarily doing something against best practices. I think in SwiftUI, the concepts of data model storage and manipulation quickly become more complex than, for example, what Apple tends to show in its demo code. With a real app, with a single source of truth, like you seem to be using, you're going to have to come up with some ways to bind the data to your views.

struct TaskView : View {
    var taskIdentifier: String // Passed from parent view
    
    @EnvironmentObject private var taskStore: TaskStore
    
    private var taskBinding : Binding<Task> {
        Binding {
            taskStore.tasks[taskIdentifier] ?? .init(identifier: "", title: "", tags: [])
        } set: {
            taskStore.tasks[taskIdentifier] = $0
        }
    }
    
    var body: some View {
        TextField("Task title", text: taskBinding.title)
    }
}

Answer 2

You are correct to model your data with value types and manage lifecycle and side-effects with a reference type. The bit you are missing is that Task doesn't implement the Identifiable<\/code> protocol which enables SwiftUI to keep track of the data in a List<\/code> or ForEach<\/code> . Implement that as follows:

struct Task: Identifiable {
    var id: String
    var title: String
    var tags: [String] // Array of tag identifiers
}