ios - Swift:为什么闭包函数调用迟了

Question

我有两个功能:

class ProductController: NSObject {

    var products = [Product]()

    func getData(){

        let json = JSONParser()
        let path = "http://localhost:8888/myApi/product/read.php"

        json.getRequest(url: path) { (products) in
            self.products = products
            print("closure")
            print(self.products)
        }
    }

    func getPr() -> [Product]{
        return self.products
    }
}

我正在打电话:

 let pc = ProductController()
 pc.getData()
 print(pc.getPr())

但是 pc.getData() 的调用总是最后一次，所以我从 pc.getPr() 得到了 []。如何在调用 getPr() 之前从 getData() 获取产品？

Answer 1

你可以试试补全

func getData(completion: @escaping (_ anyData: [Product]) -> Void) {
  let json = JSONParser()
  let path = "http://localhost:8888/myApi/product/read.php"

  json.getRequest(url: path) { (products) in
  self.products = products
  print("closure")
  print(self.products)
  completion(products)

}

然后这样调用它

pc.getData() { products in

    print(products)
    print(pc.getPr())
}