我如何使用位于列表内部的按钮删除列表中的项目？

huangapple
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英文:

How would I delete items from a list with a button inside that list?

问题

SwiftUI
[这是列表和按钮的代码]

  1. ForEach(items, id: \.self) { current in 
  2.     VStack(alignment: .leading) {
  3.         Text("\(current.task)")
  4.             .padding(2)
  5.         Text("\(dateFormatter.string(from: current.date))")
  6.         Button(action: {}, 
  7.                label: {
  8.                     Image(systemName: 
  9.                       "checkmark.rectangle.fill")
  10.                         .resizable()
  11.                         .frame(width: 50, height: 35)
  12.                }) 
  13.     }
  14. }

Items 是包含字符串和日期的数组。以下是其代码：

  1. @State var items: [Tasks] = [Tasks(task: "测试", date: Date())]

这是 Tasks 结构体：

  1. struct Tasks: Hashable {
  2.     let task: String
  3.     let date: Date 
  4. }

这是我的列表视图

我希望用户能够点击每个列表项下面的按钮，以删除该列表项。我目前使用 onDelete 方法，但我更希望在每个列表项下面有一个确认按钮，允许用户删除该列表项。

  1. @State var counter = -1

我尝试使用一个计数器，使其在 ForEach 循环运行时递增，并在该 ForEach 循环内创建一个等于计数器值的新变量。然而，我无法在按钮内访问该变量以用作索引。

英文:

SwiftUI
[This is the code for the list and my button]

  1. ForEach(items, id: \.self) { current in 
  2.                 VStack(alignment: .leading) {
  3.                     Text("\(current.task)")
  4.                         .padding(2)
  5.                     Text("\(dateFormatter.string(from: current.date))")
  6.                     Button(action: {}, 
  7.                            label: {
  8.                                     Image(systemName: 
  9.                                       "checkmark.rectangle.fill")
  10.                             .resizable()
  11.                             .frame(width: 50, height: 35)
  12.                            }) 
  13. }

Items is my array containing a string and a date. Here is the code for it:

  1. @State var items:[Tasks] = [Tasks(task: "Test", date: Date())]

And here is Tasks:

  1. struct Tasks: Hashable {
  2.   let task: String
  3.   let date: Date 
  4. }

This is my list view

I want to have a user be able to click a button under each list item and it will remove that list item. I am currently using the onDelete method but I would prefer to have a confirm button in each list item that would allow the user to remove that list item.

  1.     @State var counter = -1

I tried using a counter that would increase by 1 each time the ForEach loop ran and create a new variable inside of that ForEach loop equal to it. However I could not access the variable inside of the button to use as an index.

答案1

得分: 1

根据您当前的代码结构，假设每个 task: String 都是唯一的，您可以将以下代码添加到您的 Button 操作中：

  1. Button(action: {
  2.     if let index = items.firstIndex(where: {$0.task == current.task}) {
  3.         items.remove(at: index)
  4.     }
  5. },
  6. label: {
  7.     Image(systemName: "checkmark.rectangle.fill")
  8.         .resizable()
  9.         .frame(width: 50, height: 35)
  10. })

然而，为了使代码更加健壮，建议为您的 Task 添加一个 id 属性，并同时重命名它，因为Swift已经将 Task 定义为其异步/等待框架的一部分。

以下是我用于测试我的答案的完整代码：

  1. struct MyTask: Identifiable, Hashable {
  2.     let id = UUID()
  3.     let task: String
  4.     let date: Date
  5. }
  7. struct ContentView: View {
  8.     @State var items:[MyTask] = [
  9.         MyTask(task: "Test1", date: Date()),
  10.         MyTask(task: "Test2", date: Date().addingTimeInterval(60*60*24*44)),
  11.         MyTask(task: "Test3", date: Date().addingTimeInterval(60*60*24*88))
  12.     ]
  14.     var body: some View {
  15.         ForEach(items) { current in
  16.             VStack(alignment: .leading) {
  17.                 Text(current.task).padding(2)
  18.                 Text(dateFormatter.string(from: current.date))
  19.                 Button(action: {
  20.                     if let index = items.firstIndex(where: {$0.id == current.id}) {
  21.                         items.remove(at: index)
  22.                     }
  23.                 },
  24.                 label: {
  25.                     Image(systemName: "checkmark.rectangle.fill").resizable()
  26.                         .frame(width: 50, height: 35)
  27.                 })
  28.             }
  29.         }
  30.     }
  32.     var dateFormatter: DateFormatter = {
  33.         let frmt = DateFormatter()
  34.         frmt.dateFormat = "yyyy-MMM-dd"
  35.         return frmt
  36.     }()
  37. }

请注意，我已经将 HTML 实体（例如 < 和 "）转换为正常的Swift代码。

英文:

Using your current code structure, assuming each task: String is unique, you could just add this to your Button action:

  1.  Button(action: {
  2.      if let index = items.firstIndex(where: {$0.task == current.task}) {
  3.          items.remove(at: index)
  4.      }
  5.  },
  6.         label: {
  7.      Image(systemName: "checkmark.rectangle.fill")
  8.          .resizable()
  9.          .frame(width: 50, height: 35)
  10.  })

However, it would be more robust to add an id property to your Task, and
at the same time rename it, because Swift already defines Task as part of its async/await framework.

Here is the complete code I use to test my answer:

  1. struct MyTask: Identifiable, Hashable { // <--- here
  2.   let id = UUID() // <--- here
  3.   let task: String
  4.   let date: Date
  5. }
  7. struct ContentView: View {
  8.     @State var items:[MyTask] = [
  9.         MyTask(task: "Test1", date: Date()),
  10.         MyTask(task: "Test2", date: Date().addingTimeInterval(60*60*24*44)),
  11.         MyTask(task: "Test3", date: Date().addingTimeInterval(60*60*24*88))
  12.     ]
  13.     
  14.     var body: some View {
  15.         ForEach(items) { current in     // <--- here
  16.             VStack(alignment: .leading) {
  17.                 Text(current.task).padding(2)  // <--- here
  18.                 Text(dateFormatter.string(from: current.date))  // <--- here
  19.                 Button(action: {
  20.                     // --- here
  21.                     if let index = items.firstIndex(where: {$0.id == current.id}) {
  22.                         items.remove(at: index)
  23.                     }
  24.                 },
  25.                        label: {
  26.                     Image(systemName: "checkmark.rectangle.fill").resizable()
  27.                         .frame(width: 50, height: 35)
  28.                 })
  29.             }
  30.         }
  31.     }
  32.     
  33.     var dateFormatter: DateFormatter = {
  34.         let frmt = DateFormatter()
  35.         frmt.dateFormat = "yyyy-MMM-dd"
  36.         return frmt
  37.     }()
  38. }

huangapple
  • 本文由 发表于 2023年2月19日 06:31:44
  • 转载请务必保留本文链接：https://go.coder-hub.com/75496794.html
  • arrays
  • list
  • swiftui
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