topic Re: Download MMPK (not PrePlannedMapArea) in ArcGIS Runtime SDK for iOS Questions

Download MMPK (not PrePlannedMapArea)

RTC — Thu, 02 Sep 2021 21:22:52 GMT

I have several MMPK maps on AGOL that I want to download into my app (not side load).

What are the proper steps to get the mmpk file downloaded into the app?

Re: Download MMPK (not PrePlannedMapArea)

Nicholas-Furness — Thu, 02 Sep 2021 23:48:55 GMT

You should be able to create an AGSPortalItem for the AGOL item for the MMPK, and then call fetchData() on that to get NSData. You can then call NSData.writeToFile() to write that MMPK to your iOS filesystem as a .mmpk file.

Re: Download MMPK (not PrePlannedMapArea)

RTC — Fri, 03 Sep 2021 01:21:19 GMT

Thank you Nicholas, I will give that a try.

Re: Download MMPK (not PrePlannedMapArea)

RTC — Wed, 08 Sep 2021 03:25:14 GMT

Hello Nicholas,

I tried to load the portalItem as per your instructions but can't seem to get the portal data to load. When I call the fetchData, noting happens. I can see in the AGS logs that the request get sent but there is never a response. No errors, no data, nothing. Here is how I am calling fetchData, do you see any issues? Thanks for your assistance!

// tried this way let portalItem = AGSPortalItem(url: portal, itemID: map.itemId) // also tried this way let portalItem = AGSPortalItem(url: myURL) // load portalItem portalItem.load {error in if let error = error { print("Error load mobile map package (mmpk) failed: \(error)") return } if portalItem.type == .mobileMapPackage { print("MMPK load completed") // fetch portal data (This never returns, no error, no data, no response) portalItem.fetchData { data, error in if let error = error { print("Error fetch data mobile map package failed: \(error)") return } if data == nil { print("Error MMPK fetch failed: no data") } else { print("MMPK fetch data mobile map package completed") do { try data?.write(to: downloadDirectory) print("MMPK write data mobile map package completed") } catch { print("Error MMPK write data failed: \(error.localizedDescription)") } } } } else { print("Error MMPK load mobile map package (mmpk) failed") } }

Re: Download MMPK (not PrePlannedMapArea)

Nicholas-Furness — Wed, 08 Sep 2021 14:26:08 GMT

Hi.

I expect that the AGSPortalItem is going out of scope and is being released before fetchData completes and calls into the completion block. Try keeping a strong reference to the AGSPortalItem (maybe make it a var on your class instance). You can nil it out from within the completion block if you need to.

Re: Download MMPK (not PrePlannedMapArea)

Nicholas-Furness — Wed, 08 Sep 2021 21:17:38 GMT

There is another way to download the MMPK. You can use AGSRequestOperation. The advantage here is that you have access to the download progress, and you can also avoid having to create a large Data object in memory. The AGSRequestOperation can stream the download directly to your file. You would do something like this:

func downloadMMPK(from portalItemForMMPK: AGSPortalItem) { portalItemForMMPK.load { [weak self] error in guard let self = self else { return } if let error = error { print("Unable to load the portal item: \(error.localizedDescription)") return } guard let portalUrl = portalItemForMMPK.portal.url, let itemDataUrl = URL(string: "\(portalUrl)/sharing/rest/content/items/\(portalItemForMMPK.itemID)/data"), let docsFolder = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else { return } let mmpkLocation = docsFolder.appendingPathComponent(portalItemForMMPK.name, isDirectory: false) let request = AGSRequestOperation(url: itemDataUrl) request.outputFileURL = mmpkLocation request.registerListener(self) { result, error in if let error = error { print("Unable to download the file: \(error.localizedDescription)") return } guard let result = result as? URL, result.isFileURL else { return } let mmpk = AGSMobileMapPackage(fileURL: result) mmpk.load { error in if let error = error { print("Unable to open the mmpk file: \(error.localizedDescription)") return } if let mapFromMMPK = mmpk.maps.first { self.mapView.map = mapFromMMPK } } } request.progressHandler = { (downloaded, total) in print("Downloaded \(100 * downloaded/total)%. \(total - downloaded) bytes remaining") } self.progressView.observedProgress = request.progress AGSOperationQueue.shared().addOperation(request) } }

Note, in that code, I've added a ProgressView to my ViewController. I'm actually showing progress twice - once printed to the console in the AGSRequestOperation's progressHandler, and at the same time by just having my UI's ProgressView lean on the AGSRequestOperation's progress object.

The key is defining the outputFileURL property on the AGSRequestOperation. If you do that, the registered listener will be passed a URL object, otherwise it'll get a Data object.

Re: Download MMPK (not PrePlannedMapArea)

RTC — Wed, 08 Sep 2021 21:21:31 GMT

Excellent, I will give that a try, thanks!

Re: Download MMPK (not PrePlannedMapArea)

RTC — Wed, 15 Sep 2021 00:19:31 GMT

Thanks Nicholas, I think this is the best solution for downloading mmpk files to an iOS app.

Re: Download MMPK (not PrePlannedMapArea)

GauravBansal0025 — Fri, 25 Mar 2022 07:33:10 GMT

How we can do the same in Android ??