Alamofire被用于在一次请求下载多个较大的文件。 我可以使用
单独查看每个文件的进度Alamofire.request(.GET, imageURL).progress
但我想立刻跟踪所有公开会议的进度,不知道该怎么做。 (假设我有15个文件同时下载) 我阅读了很多教程来解决单个文件的进度,但整个会话没有。
是否有可能通过Alamofire跟踪进展情况,如果是,如何进行?
答案 0 :(得分:4)
在iOS9中,您可以创建自己的NSProgress
对象,并观察,例如fractionCompleted
。然后你可以addChild
:
private var observerContext = 0
class ViewController: UIViewController {
private var progress: NSProgress!
override func viewDidLoad() {
super.viewDidLoad()
progress = NSProgress()
progress.addObserver(self, forKeyPath: "fractionCompleted", options: .New, context: &observerContext)
downloadFiles()
}
deinit {
progress?.removeObserver(self, forKeyPath: "fractionCompleted")
}
private func downloadFiles() {
let filenames = ["as17-134-20380.jpg", "as17-140-21497.jpg", "as17-148-22727.jpg"]
let baseURL = NSURL(string: "http://example.com/path")!
progress.totalUnitCount = Int64(filenames.count)
progress.completedUnitCount = 0
for filename in filenames {
let url = baseURL.URLByAppendingPathComponent(filename)
let childProgress = Alamofire.request(.GET, url.absoluteString)
.response() { request, response, data, error in
// process response
}
.progress
progress.addChild(childProgress, withPendingUnitCount: 1)
}
}
override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) {
if context == &observerContext {
if keyPath == "fractionCompleted" {
let percent = change![NSKeyValueChangeNewKey] as! Double
print("\(percent)")
}
} else {
super.observeValueForKeyPath(keyPath, ofObject: object, change: change, context: context)
}
}
}
如果您还需要iOS 7/8支持,可以拨打becomeCurrentWithPendingUnitCount
和resignCurrent
:
for filename in filenames {
let url = baseURL.URLByAppendingPathComponent(filename)
progress.becomeCurrentWithPendingUnitCount(1)
Alamofire.request(.GET, url.absoluteString)
.response() { request, response, data, error in
// process response
}
progress.resignCurrent()
}
如果您使用的是AFNetworking,则它是相同的过程(即上述相同的viewDidLoad
,observeValueForKeyPath
和deinit
方法),而不是检索Alamofire progress
属性,您改为使用AFHTTPSessionManager
方法downloadProgressForTask
来获取与NSProgress
相关联的NSURLSessionTask
。例如:
private func getFiles() {
let filenames = ["as17-134-20380.jpg", "as17-140-21497.jpg", "as17-148-22727.jpg"]
let manager = AFHTTPSessionManager()
manager.responseSerializer = AFHTTPResponseSerializer()
let baseURL = NSURL(string: "http://example.com/path")!
progress.totalUnitCount = Int64(filenames.count)
progress.completedUnitCount = 0
for filename in filenames {
let url = baseURL.URLByAppendingPathComponent(filename)
let task = manager.GET(url.absoluteString, parameters: nil, progress: nil, success: { task, responseObject in
// do something with responseObject
print(url.lastPathComponent! + " succeeded")
}, failure: { task, error in
// do something with error
print(error)
})
if let downloadTask = task, let childProgress = manager.downloadProgressForTask(downloadTask) {
progress.addChild(childProgress, withPendingUnitCount: 1)
}
}
}
或者,如果使用下载任务:
private func downloadFiles() {
let filenames = ["as17-134-20380.jpg", "as17-140-21497.jpg", "as17-148-22727.jpg"]
let manager = AFHTTPSessionManager()
let baseURL = NSURL(string: "http://example.com/path")!
progress.totalUnitCount = Int64(filenames.count)
progress.completedUnitCount = 0
let documents = try! NSFileManager.defaultManager().URLForDirectory(.DocumentDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: false)
for filename in filenames {
let url = baseURL.URLByAppendingPathComponent(filename)
let task = manager.downloadTaskWithRequest(NSURLRequest(URL: url), progress: nil, destination: { (temporaryURL, response) -> NSURL in
return documents.URLByAppendingPathComponent(url.lastPathComponent!)
}, completionHandler: { response, url, error in
guard error == nil else {
print(error)
return
}
if let name = url?.lastPathComponent {
print("\(name) succeeded")
}
})
if let childProgress = manager.downloadProgressForTask(task) {
progress.addChild(childProgress, withPendingUnitCount: 1)
}
task.resume()
}
}