Question

我正在使用SwiftUI构建iOS应用。当我单击“完成”按钮，并且entry属性不是nil，并且我没有使用DatePicker TextField或TextView时，我得到AppDelegate中的以下运行时错误：

线程1：EXC_BAD_ACCESS（代码= 2，地址= 0x7ffee2a83fe8）

这是我的代码：

import SwiftUI

struct EditView: View {
    @State var entry: Entry?
    @ObservedObject var entries: Entries
    
    @State var newDate: Date
    @State var newTitle: String
    @State var newBody: String
    
    @Environment(\.presentationMode) var presentationMode
    
    init(entries: Entries, entry: Entry?) {
        UIScrollView.appearance().keyboardDismissMode = .onDrag
        
        _entry = .init(initialValue: entry)
        _entries = .init(initialValue: entries)
    
        _newDate = .init(initialValue: entry?.date ?? Date())
        _newTitle = .init(initialValue: entry?.title ?? "")
        _newBody = .init(initialValue: entry?.body ?? "")
    }
    
    var body: some View {
        GeometryReader { geometry in
            Form {
                Section {
                DatePicker("Date", selection: self.$newDate, in: ...Date(), displayedComponents: .date)
                    .labelsHidden()
                }
                
                Section {
                TextField("Title (optional)", text: self.$newTitle)
                    
                TextView(placeholder: "Entry", text: self.$newBody)
                    .frame(width: geometry.size.width, height: 250, alignment: .topLeading)
                }
            }
        }
        .navigationBarItems(trailing:
            Button("Done") {
                
                if let entry = self.entry {
                    
                    if let index = self.entries.list.firstIndex(of: entry) {
                        
                        self.entries.list[index] = Entry(date: self.newDate, title: self.newTitle, body: self.newBody)
                    }
                } else {
                    self.entries.list.append(Entry(date: self.newDate, title: self.newTitle, body: self.newBody))
                }
                
                self.presentationMode.wrappedValue.dismiss()
            })
    }
}

import Foundation

class Entries: ObservableObject {
    @Published var list = [Entry]()
}

class Entry: ObservableObject, Identifiable, Equatable {
    static func == (lhs: Entry, rhs: Entry) -> Bool {
        return lhs.id == rhs.id
    }
    
    let id = UUID()
    
    @Published var date: Date
    var dateString: String {
        let formatter = DateFormatter()
        formatter.dateStyle = .medium
        formatter.timeStyle = .none
        
        return formatter.string(from: self.date)
    }
    
    @Published var title: String
    @Published var body: String
    
    init(date: Date, title: String, body: String) {
        self.date = date
        self.title = title
        self.body = body
    }
    
    static let example = Entry(date: Date(), title: "I wrote some swift today", body: "Today I wrote some swift for an app I'm developing. It was very fun.")

当我删除self.presentationMode.wrappedValue.dismiss()行时，问题就消失了。虽然，我需要那条线来消除观点。为什么会发生这种情况，我该如何解决？如果我的代码完全混乱，请原谅我。谢谢！

Answer 1

在关闭过程中它似乎尝试更新，尝试推迟一点关闭过程

DispatchQueue.main.async { // defer to next event
   self.presentationMode.wrappedValue.dismiss()
}

关闭未编辑的视图时崩溃-SwiftUI

1 个答案: