Hi @cyber_denis,
No, that sample you are providing is not actually downloading a file. When you are trying to load an Entity, as you indicate in your line
Code Block | let entity = try? Entity.load(contentsOf: fileUrl) |
the loading of the file is expected to come from local storage on your device (either by way of an asset being bundled with the app when you compile it, or by downloading an asset).
For what you are trying to achieve, you will need to use some methodology of downloading the file from the web, saving to a location that you app has access to (such as the app's Documents directory), and then reference that path when trying to load your Entity or AR object. The first example in Apple's
Downloading Files from Websites will get you there.
For example, here is an updated version of your ViewController.swift. See notations below;
Code Block | import UIKit |
| import ARKit |
| import QuickLook |
|
| class ViewController: UIViewController, QLPreviewControllerDataSource { |
| |
| // 1 |
| var modelURL: URL? |
|
| override func viewDidLoad() { |
| super.viewDidLoad() |
| |
| // 2 |
| self.downloadSampleUSDZ() |
| } |
|
| @IBAction func startDecoratingButtonPressed(_ sender: Any) { |
| |
| // 3 |
| guard modelURL != nil else { return } |
| let previewController = QLPreviewController() |
| previewController.dataSource = self |
| present(previewController, animated: true, completion: nil) |
| |
| } |
| |
| // 4 |
| func downloadSampleUSDZ() { |
| let url = URL(string: "https://developer.apple.com/augmented-reality/quick-look/models/drummertoy/toy_drummer.usdz")! |
| let downloadTask = URLSession.shared.downloadTask(with: url) { urlOrNil, responseOrNil, errorOrNil in |
| |
| guard let fileURL = urlOrNil else { return } |
| do { |
| let documentsURL = try |
| FileManager.default.url(for: .documentDirectory, |
| in: .userDomainMask, |
| appropriateFor: nil, |
| create: false) |
| let savedURL = documentsURL.appendingPathComponent(url.lastPathComponent) |
| try FileManager.default.moveItem(at: fileURL, to: savedURL) |
| self.modelURL = savedURL |
| } catch { |
| print ("file error: \(error)") |
| } |
| } |
| downloadTask.resume() |
| } |
| |
| func numberOfPreviewItems(in controller: QLPreviewController) -> Int { return 1 } |
| |
| func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem { |
| // 5 |
| let previewItem = ARQuickLookPreviewItem(fileAt: self.modelURL!) |
| previewItem.canonicalWebPageURL = URL(string: "https://developer.apple.com/augmented-reality/quick-look/models/drummertoy/") |
| previewItem.allowsContentScaling = false |
| return previewItem |
| } |
| } |
1) Add a new variable to your ViewController.swift file, which will hold the
local URL of the file, once it's been downloaded and saved to storage.
2) Call a new function (discussed below), to download the file from a web URL.
3) Make sure that we've set the
modelURL, hereby confirming the file was downloaded successfully. Otherwise, do not do anything, as we have nothing to preview.
4) Again, this is adapted from the
Downloading Files from Websites documentation, but you are establishing the URL of the file you want to download, and configuring a task to download that file. Once the file is downloaded, we save it to the app's Documents directory, using the original file name, and set
modelURL to be the path to the local URL of the downloaded file.
5) We set the URL of the
ARQuickLookPreviewItem to the local URL of the file, then preview.
This is a very abstract example, which does not take into account things like error handling, keeping the user informed of what is happening (otherwise they are just tapping the button repeatedly until the file is ready), and a litany of other considerations to deliver an ideal user experience (including adding the ability to dynamically provide the web URL of the file(s) you wish to download, as this example is hard-coding the web URL to "toy_drummer.usdz"). However, this code does compile when I test on my device, and I can preview the AR model after it downloads from the web.
