从SCNScene网址获取下载进度

It is my understanding that whilst it appears that the following method would take a remote URL in actuality it doesn't (although I could be wrong):convenience init(url: URL, options: [SCNSceneSource.LoadingOption : Any]? = nil) throws无论如何在这里回答您的问题都是一个示例(可能有点OTT，但希望它也会对其他人有所帮助).Anyway to answer your question here is an example for you (which is probably a bit OTT, but hopefully it will help others as well).让我们说我们在以下URL处有一个SCNScene文件:Lets say we an SCNScene file at the following URL:http://stackOverflow.com/stackOverFlow.scn首先，我们需要像这样为ProgressInfo创建变量:Firstly we need to create variables for our ProgressInfo like so: var loading: UIAlertController! var loadingIndicator: UIActivityIndicatorView! var downloadString: String = "Downloading"然后，我们将创建一个URLSession来下载文件，如下所示:Then what we will do is create a URLSession to download the file like so: /// Downloads An SCNFile From A Remote URL func downloadSceneTask(){ //1. Get The URL Of The SCN File guard let url = URL(string: "http://stackOverflow.com/stackOverFlow.scn") else { return } //2. Create The Download Session let downloadSession = URLSession(configuration: URLSession.shared.configuration, delegate: self, delegateQueue: nil) //3. Create The Download Task & Run It let downloadTask = downloadSession.downloadTask(with: url) downloadTask.resume() //4. Show The Progress Alert DispatchQueue.main.async { self.loading = UIAlertController(title: nil, message: self.downloadString , preferredStyle: .alert) let loadingIndicator = UIActivityIndicatorView(frame: CGRect(x: 10, y: 5, width: 50, height: 50)) loadingIndicator.hidesWhenStopped = true loadingIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.gray loadingIndicator.startAnimating(); self.loading.view.addSubview(loadingIndicator) self.present(self.loading, animated: true, completion: nil) } }请注意，我已经创建了一个variable引起的downloadString，我们稍后将对其进行更改.Note that I have create a variable caused downloadString which we change later.然后，我们将参考以下URLSession委托:We will then make reference to following URLSession Delegates e.g:class ViewController: UIViewController, URLSessionDelegate, URLSessionDownloadDelegate {}我们的示例将调用以下函数:Which for our example will call the following functions:第一个跟踪我们下载进度的信息，您可以在其中处理诸如在HUD或使用progressIndicator中显示进度的事情:The 1st to track the progress of our download in which you can handle things like showing the progress in a HUD or using a progressIndicator:func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) { print("Downloaded \(totalBytesWritten) / Of \(totalBytesExpectedToWrite) Bytes") DispatchQueue.main.async { self.loading.message = "Downloaded \(totalBytesWritten) / Of \(totalBytesExpectedToWrite) Bytes" }}文件下载后处理的第二个:The 2nd to handle when the file has downloaded:func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {//1. Remove The Loading View loading.dismiss(animated: true, completion: nil)//2. Create The Filenamelet fileURL = getDocumentsDirectory().appendingPathComponent("stackOverFlow.scn")//3. Copy It To The Documents Directorydo { try FileManager.default.copyItem(at: location, to: fileURL) print("Successfuly Saved File \(fileURL)") //4. Load The Model loadModel()} catch { print("Error Saving: \(error)") }}请注意，在这种方法中，我正在使用以下功能来检索下载的文件并将其复制到documents directory:Note that in this method I am making use of the following function to retrieve and copy the downloaded file to the documents directory:/// Returns The Documents Directory////// - Returns: URLfunc getDocumentsDirectory() -> URL {let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)let documentsDirectory = paths[0]return documentsDirectory}一旦文件被下载并复制到整个文件中，我们(4)就会这样调用我们的loadModel function:Once the file has been downloaded and copied across we then (4) call our loadModel function like so:/// Loads The SCNFile From The Documents Directoryfunc loadModel(){ //1. Get The Path Of The Downloaded File let downloadedScenePath = getDocumentsDirectory().appendingPathComponent("stackOverFlow.scn") do { //2. Load The Scene Remembering The Init Takes ONLY A Local URL let modelScene = try SCNScene(url: downloadedScenePath, options: nil) //3. Create A Node To Hold All The Content let modelHolderNode = SCNNode() //4. Get All The Nodes From The SCNFile let nodeArray = modelScene.rootNode.childNodes //5. Add Them To The Holder Node for childNode in nodeArray { modelHolderNode.addChildNode(childNode as SCNNode) } //6. Set The Position modelHolderNode.position = SCNVector3(0, 0, -1.5) //7. Add It To The Scene self.augmentedRealityView?.scene.rootNode.addChildNode(modelHolderNode) } catch { print("Error Loading Scene") }}请注意，这是一个非常粗糙的示例，并没有涉及检查文件是否存在，缩放等内容，但是它足以帮助您实现所需的内容... Please note that this is a very crude example, and doesn't cover things like checking if the file exists, scaling etc, but it should be enough to help you achieve what you are looking for... 这篇关于从SCNScene网址获取下载进度的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！