如何在 SwiftUI 列表中获取行索引? [英] How to get row index in SwiftUI List?
本文介绍了如何在 SwiftUI 列表中获取行索引?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我想要一个编号列表,其中每一行都有一个数字.
I would like to have a numbered list, where every row has a number.
像这样
但我在 List
初始化程序
but I don't see right API for that in List
initialisers
此时我看到了这个解决方法
At this moment I see this workaround
var persons = ["Boris", "Anna", "Tom"]
// MARK: - Body
func body(props: Props) -> some View {
List(persons.indices, id: \.self) { index in
Text("\(index) \(self.persons[index])")
}
}
推荐答案
使用 .indices() 不是一种解决方法,而是一种正确的方法.
Using .indices() is not a workaround, it is a proper way of doing it.
或者,您也可以将发行说明中的代码用于 indexed() 数组:
Alternatively, you can also use the code in the release notes for an indexed() array:
struct ContentView: View {
var persons = ["Boris", "Anna", "Tom"]
var body: some View {
VStack {
List(persons.indexed(), id: \.1.self) { idx, person in
Text("\(idx) - \(person)")
}
}
}
}
// This is taken from the Release Notes, with a typo correction, marked below
struct IndexedCollection<Base: RandomAccessCollection>: RandomAccessCollection {
typealias Index = Base.Index
typealias Element = (index: Index, element: Base.Element)
let base: Base
var startIndex: Index { base.startIndex }
// corrected typo: base.endIndex, instead of base.startIndex
var endIndex: Index { base.endIndex }
func index(after i: Index) -> Index {
base.index(after: i)
}
func index(before i: Index) -> Index {
base.index(before: i)
}
func index(_ i: Index, offsetBy distance: Int) -> Index {
base.index(i, offsetBy: distance)
}
subscript(position: Index) -> Element {
(index: position, element: base[position])
}
}
extension RandomAccessCollection {
func indexed() -> IndexedCollection<Self> {
IndexedCollection(base: self)
}
}
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