[英]Howto Update a gui (progressview) from a download delegate in swift
我有一個DownloadSessionDelegate類來處理大文件的下載過程。 我想在進度視圖中展示進展。 有關下載狀態的信息位於我的DownloadSessionDelegate類中。 現在我不知道如何在該課程之外更新我的進度視圖。
怎么做呢?
class DownloadSessionDelegate : NSObject, NSURLSessionDelegate, NSURLSessionDownloadDelegate {
var handlerQueue: [String : CompleteHandlerBlock]!
...
...
...
func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {
println("session \(session) download task \(downloadTask) wrote an additional \(bytesWritten) bytes (total \(totalBytesWritten) bytes) out of an expected \(totalBytesExpectedToWrite) bytes.")
progressView.setProgress(0.5, animated: true); // <<<Howto reference the progressView
}
}
從我的ViewController.swift觸發下載:
func download_zip(sURL: String, sToLocation: String) {
let progressView = UIProgressView(progressViewStyle: .Bar);
progressView.center = view.center;
progressView.progress = 1/2;
progressView.trackTintColor = UIColor.lightGrayColor();
progressView.tintColor=UIColor.blueColor();
view.addSubview(progressView);
var delegate = DownloadSessionDelegate.sharedInstance;
delegate.storePath=sToLocation;
struct SessionProperties {
static let identifier : String! = "url_session_background_download"
}
var configuration = NSURLSessionConfiguration.backgroundSessionConfigurationWithIdentifier(SessionProperties.identifier)
var backgroundSession = NSURLSession(configuration: configuration, delegate: delegate, delegateQueue: nil)
var url = NSURLRequest(URL: NSURL(string: sURL)!)
var downloadTask = backgroundSession.downloadTaskWithRequest(url)
downloadTask.resume()
}
要從另一個類引用進度視圖,您需要將進度視圖的實例傳遞給需要其引用的類,在您的情況下:
class DownloadSessionDelegate : NSObject, NSURLSessionDelegate, NSURLSessionDownloadDelegate {
var handlerQueue: [String : CompleteHandlerBlock]!
var progressView: UIProgressView!
...
...
...
func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {
println("session \(session) download task \(downloadTask) wrote an additional \(bytesWritten) bytes (total \(totalBytesWritten) bytes) out of an expected \(totalBytesExpectedToWrite) bytes.")
progressView.setProgress(0.5, animated: true); // <<<Howto reference the progressView
}
}
ViewContoller
func download_zip(sURL: String, sToLocation: String) {
let progressView = UIProgressView(progressViewStyle: .Bar);
progressView.center = view.center;
progressView.progress = 1/2;
progressView.trackTintColor = UIColor.lightGrayColor();
progressView.tintColor=UIColor.blueColor();
view.addSubview(progressView);
var delegate = DownloadSessionDelegate.sharedInstance;
delegate.storePath=sToLocation;
//here you pass progressView from ViewController to DownloadSessionDelegate
delegate.progressView = progressView
struct SessionProperties {
static let identifier : String! = "url_session_background_download"
}
var configuration = NSURLSessionConfiguration.backgroundSessionConfigurationWithIdentifier(SessionProperties.identifier)
var backgroundSession = NSURLSession(configuration: configuration, delegate: delegate, delegateQueue: nil)
var url = NSURLRequest(URL: NSURL(string: sURL)!)
var downloadTask = backgroundSession.downloadTaskWithRequest(url)
downloadTask.resume()
}
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