Swift：将Alamofire和SwiftyJSON与分页JSON API一起使用

I can’t tell from your post if you get valid JSON back for each page call or whether you need to put them altogether to complete the JSON. So let’s walk through both cases.

选项1 – 每个页面的有效JSON

你已经非常接近了,你只需稍微调整你的JSON解析并存储结果.这就是它的样子.

class PagedDownloader {
    var pagedResults = [AnyObject]()

    func loadSomeJSONDataFromPagedEndPoint(page: Int) {
        let request = Alamofire.request(.GET,"http://example.com/json/(page)")
        request.responseJSON { [weak self] _,jsonData,_ in
            if let strongSelf = self {
                let json = JSON(jsonData!)

                let totalPages = json["totalPages"].stringValue.toInt()!
                let currentPage = json["currentPage"].stringValue.toInt()!

                let results = json["results"].arrayObject!
                strongSelf.pagedResults += results

                if currentPage < totalPages {
                    strongSelf.loadSomeJSONDataFromPagedEndPoint(currentPage + 1)
                } else {
                    strongSelf.parsePagedResults()
                }
            }
        }
    }

    func parsePagedResults() {
        let json = JSON(pagedResults)
        println(json)
    }
}

您似乎了解SwiftyJSON的方式,因此我将让您处理parsePagedResults实现.

选项2 – 必须组装页面才能创建有效的JSON

分页JSON

首先,你不能解析部分JSON,它只是不起作用. NSJSONSerialization将失败.这意味着您不能将responseJSON序列化程序与分页JSON一起使用,因为数据始终为nil,错误始终是json序列化错误.长话短说,你需要缓存所有数据,直到它是有效的JSON,然后你可以解析.

存储分页JSON

如果你要存储它,这就是它可能看起来像一个没有Alamofire混合的简单例子.

class Pager {

    let page1 = "{"currentPage":"1","totalPages":"3","results":[{"id":"123","name":"Bob"},"
    let page2 = "{"id":"456","name":"Sally"},{"id":"234","name":"Christian"},"
    let page3 = "{"id":"567","name":"Jerry"},{"id":"345","name":"John"}]}"

    let pages: [String]
    let jsonData: NSMutableData

    init() {
        self.pages = [page1,page2,page3]
        self.jsonData = NSMutableData()
    }

    func downloadPages() {
        for (index,page) in enumerate(pages) {
            jsonData.appendData(page.dataUsingEncoding(NSUTF8StringEncoding,allowLossyConversion: false)!)
        }

        let json = JSON(data: jsonData)
        println(json)

        if let totalPages = json["totalPages"].string?.toInt() {
            println("Total Pages Value: (totalPages)")
        }
    }
}

Your bonus question is answered at the end of that code chunk. You don’t want to use description from SwiftyJSON,but instead the string optional cast and then optional chain into the toInt method.

使用Alamofire进行分页和存储

既然您已经有了一个如何将JSON页面写入数据块的简单示例,那么让我们看看如何在Alamofire中使用相同的方法与响应序列化器一起使用.

class Downloader {
    var jsonData = NSMutableData()
    var totalPagesDownloaded = 0
    let totalPagesToDownload = 6

    func loadSomeJSONDataFromPagedEndPoint() {
        for page in 1...self.totalPagesToDownload {
            let request = Alamofire.request(.GET,"http://example.com/json/(page)")
            request.response { [weak self] _,_ in
                if let strongSelf = self {
                    strongSelf.jsonData.appendData(data as NSData)
                    ++strongSelf.totalPagesDownloaded

                    if strongSelf.totalPagesDownloaded == strongSelf.totalPagesToDownload {
                        strongSelf.parseJSONData()
                    }
                }
            }
        }
    }

    func parseJSONData() {
        let json = JSON(data: jsonData)
        println(json)
    }
}

使用SwiftyJSON解析生成的JSON

在parseJSONData函数中,只需使用SwiftyJSON的所有强大功能来解析您需要的值.

I’m pretty sure that covers all your possible use cases and questions. Hope that helps!