Question

我想将闭包存储在数组中。但是我不知道该怎么做，否则我的想法是完全错误的。安装如下所示时，出现错误：

Cannot convert value of type '(Reader) -> (URL) -> ()' to expected element type '(URL) -> ()'

我不明白。我的课：

class Reader {
    let fileNamesActions:[( filename:String, action:(URL) -> () )]  = [
        (filename:"goodStories.txt", action: readGoodStories),
        (filename:"badStories.txt", action: readBadStories),
        (filename:"stupidStories", action: readStupidStories)]

我已经声明了这样的函数：

    func readGoodStories(from url:URL) {
        //read, do whatever i want with url
    }
    ...

我用以下方式称呼他们：

    init (with url:URL) {    
         for (filename, action) in fileNamesActions {
             action(url.appendingPathComponent(filename))
         }
     }

Answer 1

将fileNamesActions的声明更改为lazy var，因为您正在访问其分配中的class成员，

class Reader {

    lazy var fileNamesActions:[( filename:String, action:(URL) -> () )]  = [
        (filename:"goodStories.txt", action: readGoodStories),
        (filename:"badStories.txt", action: readBadStories),
        (filename:"stupidStories", action: readStupidStories)]

    init (with url:URL) {
        for (filename, action) in fileNamesActions {
            action(url.appendingPathComponent(filename))
        }
    }

    func readBadStories(from url:URL) {
        print(url.path)
    }

    func readStupidStories(from url:URL) {
        print(url.path)
    }

    func readGoodStories(from url:URL) {
        print(url.path)
    }
}

用法

let reader = Reader(with: URL(string: "www.xxxxxxxxxx.com")!)

输出

www.xxxxxxxxxx.com/goodStories.txt
www.xxxxxxxxxx.com/badStories.txt
www.xxxxxxxxxx.com/stupidStories

如何在Swift数组中存储闭包

1 个答案: