ios – 如何将文件下载链接到进度视图
发布时间:2020-12-15 01:44:49 所属栏目:百科 来源:网络整理
导读:我的下面的按钮代码从URL下载文件,我需要将其与进度视图链接以显示下载进度. @IBAction func btnStream(sender: UIButton) { // First you need to create your audio url if let audioUrl = NSURL(string: "http://website.com/file.mp3") { // then lets c
我的下面的按钮代码从URL下载文件,我需要将其与进度视图链接以显示下载进度.
@IBAction func btnStream(sender: UIButton) { // First you need to create your audio url if let audioUrl = NSURL(string: "http://website.com/file.mp3") { // then lets create your document folder url let documentsUrl = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory,inDomains: .UserDomainMask).first as! NSURL // lets create your destination file url let destinationUrl = documentsUrl.URLByAppendingPathComponent(audioUrl.lastPathComponent!) println(destinationUrl) // to check if it exists before downloading it if NSFileManager().fileExistsAtPath(destinationUrl.path!) { println("The file already exists at path") // if the file doesn't exist } else { // just download the data from your url if let myAudioDataFromUrl = NSData(contentsOfURL: audioUrl){ // after downloading your data you need to save it to your destination url if myAudioDataFromUrl.writeToURL(destinationUrl,atomically: true) { println("file saved") } else { println("error saving file") } } } } } 如何将我的下载进度与Swift中的Progress View链接? 解决方法
以下是完整的工作示例:
import UIKit class ViewController: UIViewController,NSURLSessionDownloadDelegate { @IBOutlet weak var progressBar: UIProgressView! @IBOutlet weak var progressCount: UILabel! var task : NSURLSessionTask! var percentageWritten:Float = 0.0 var taskTotalBytesWritten = 0 var taskTotalBytesExpectedToWrite = 0 lazy var session : NSURLSession = { let config = NSURLSessionConfiguration.ephemeralSessionConfiguration() config.allowsCellularAccess = false let session = NSURLSession(configuration: config,delegate: self,delegateQueue: NSOperationQueue.mainQueue()) return session }() override func viewDidLoad() { progressBar.setProgress(0.0,animated: true) //set progressBar to 0 at start } @IBAction func doElaborateHTTP (sender:AnyObject!) { progressCount.text = "0%" if self.task != nil { return } let s = "http://www.qdtricks.com/wp-content/uploads/2015/02/hd-wallpapers-1080p-for-mobile.png" let url = NSURL(string:s)! let req = NSMutableURLRequest(URL:url) let task = self.session.downloadTaskWithRequest(req) self.task = task task.resume() } func URLSession(session: NSURLSession,downloadTask: NSURLSessionDownloadTask,didWriteData bytesWritten: Int64,totalBytesWritten writ: Int64,totalBytesExpectedToWrite exp: Int64) { println("downloaded (100*writ/exp)") taskTotalBytesWritten = Int(writ) taskTotalBytesExpectedToWrite = Int(exp) percentageWritten = Float(taskTotalBytesWritten) / Float(taskTotalBytesExpectedToWrite) progressBar.progress = percentageWritten progressCount.text = String(format: "%.01f",percentageWritten*100) + "%" } func URLSession(session: NSURLSession,didResumeAtOffset fileOffset: Int64,expectedTotalBytes: Int64) { // unused in this example } func URLSession(session: NSURLSession,task: NSURLSessionTask,didCompleteWithError error: NSError?) { println("completed: error: (error)") } // this is the only required NSURLSessionDownloadDelegate method func URLSession(session: NSURLSession,didFinishDownloadingToURL location: NSURL) { let documentsDirectoryURL = NSFileManager().URLsForDirectory(.DocumentDirectory,inDomains: .UserDomainMask).first as! NSURL println("Finished downloading!") println(documentsDirectoryURL) var err:NSError? // Here you can move your downloaded file if NSFileManager().moveItemAtURL(location,toURL: documentsDirectoryURL.URLByAppendingPathComponent(downloadTask.response!.suggestedFilename!),error: &err) { println("File saved") } else { if let err = err { println("File not saved.n(err.description)") } } } } 您可以使用NSURLSessionDownloadDelegate来实现此方法,在用户下载数据时将调用其方法. 这将显示进入progressCount标签的进程,progressBar将显示进程,因为count将递增.你可以根据需要修改它. 您可以从HERE下载此示例. (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |