我正在创建一个需要离线地图的应用程序。我正在测试MapBox，它从今天开始就支持离线地图(是的!)。我现在拥有的代码似乎可以用于下载地图，但是报告进度的委托永远不会触发，而且我不知道为什么会这样。
我的mapView拥有此类:
import UIKit
import Mapbox
class MapController: UIViewController, MGLMapViewDelegate, UIPopoverPresentationControllerDelegate {
@IBOutlet var mapView: MGLMapView!
override func viewDidLoad() {
super.viewDidLoad()
downloadIfNeeded()
mapView.maximumZoomLevel = 18
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
func downloadIfNeeded() {
MGLOfflineStorage.sharedOfflineStorage().getPacksWithCompletionHandler { (packs, error) in guard error == nil else {
return
}
for pack in packs {
let userInfo = NSKeyedUnarchiver.unarchiveObjectWithData(pack.context) as! [String: String]
if userInfo["name"] == "London" {
// allready downloaded
return
}
}
// define the download region
let sw = CLLocationCoordinate2DMake(51.212120, 4.415906)
let ne = CLLocationCoordinate2DMake(51.223781, 4.442401)
let bounds = MGLCoordinateBounds(sw: sw, ne: ne)
let region = MGLTilePyramidOfflineRegion(styleURL: MGLStyle.streetsStyleURL(), bounds: bounds, fromZoomLevel: 10, toZoomLevel: 12)
let userInfo = ["name": "London"]
let context = NSKeyedArchiver.archivedDataWithRootObject(userInfo)
MGLOfflineStorage.sharedOfflineStorage().addPackForRegion(region, withContext: context) { (pack, error) in
guard error == nil else {
return
}
// create popup window with delegate
let storyboard : UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let downloadProgress: MapDownloadController = storyboard.instantiateViewControllerWithIdentifier("MapDownloadController") as! MapDownloadController
downloadProgress.modalPresentationStyle = .Popover
downloadProgress.preferredContentSize = CGSizeMake(300, 150)
let popoverMapDownloadController = downloadProgress.popoverPresentationController
popoverMapDownloadController?.permittedArrowDirections = .Any
popoverMapDownloadController?.delegate = self
popoverMapDownloadController?.sourceView = self.mapView
popoverMapDownloadController?.sourceRect = CGRect(x: self.mapView.frame.midX, y: self.mapView.frame.midY, width: 1, height: 1)
self.presentViewController(downloadProgress, animated: true, completion: nil)
// set popup as delegate <----
pack!.delegate = downloadProgress
// start downloading
pack!.resume()
}
}
}
}
并且MapDownloadController是一个View，它显示为弹出窗口(请参见上面的代码)，并具有MGLOfflinePackDelegate:
import UIKit
import Mapbox
class MapDownloadController: UIViewController, MGLOfflinePackDelegate {
@IBOutlet var progress: UIProgressView!
@IBOutlet var progressText: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
func offlinePack(pack: MGLOfflinePack, progressDidChange progress: MGLOfflinePackProgress) {
// this function is never called, but why? <----
let completed = progress.countOfResourcesCompleted
let expected = progress.countOfResourcesExpected
let bytes = progress.countOfBytesCompleted
let MB = bytes / 1024
let str: String = "\(completed)/\(expected) voltooid (\(MB)MB)"
progressText.text = str
self.progress.setProgress(Float(completed) / Float(expected), animated: true)
}
func offlinePack(pack: MGLOfflinePack, didReceiveError error: NSError) {
// neither is this one... <----
let userInfo = NSKeyedUnarchiver.unarchiveObjectWithData(pack.context) as! [String: String]
let strError = error.localizedFailureReason
}
func offlinePack(pack: MGLOfflinePack, didReceiveMaximumAllowedMapboxTiles maximumCount: UInt64) {
// .. or this one <----
let userInfo = NSKeyedUnarchiver.unarchiveObjectWithData(pack.context) as! [String: String]
}
}
这几乎全部取自文档，因此为什么从未调用委托函数(func offlinePack)？我确实测试了断点，所以我确定不是。仍然会显示弹出窗口，并下载该区域。 (已通过观察网络流量和列出脱机包的其他代码进行检查。)
最佳答案
这是使用Minh’s answer的极其简单的current v3.2.0b1 example code实现。由于我们仍在开发v3.2.0版本，因此希望这个答案会很快过时。
import UIKit
import Mapbox
class ViewController: UIViewController, UIPopoverPresentationControllerDelegate, MGLOfflinePackDelegate {
@IBOutlet var mapView: MGLMapView!
// Array of offline packs for the delegate work around (and your UI, potentially)
var offlinePacks = [MGLOfflinePack]()
override func viewDidLoad() {
super.viewDidLoad()
mapView.maximumZoomLevel = 2
downloadOffline()
}
func downloadOffline() {
// Create a region that includes the current viewport and any tiles needed to view it when zoomed further in.
let region = MGLTilePyramidOfflineRegion(styleURL: mapView.styleURL, bounds: mapView.visibleCoordinateBounds, fromZoomLevel: mapView.zoomLevel, toZoomLevel: mapView.maximumZoomLevel)
// Store some data for identification purposes alongside the downloaded resources.
let userInfo = ["name": "My Offline Pack"]
let context = NSKeyedArchiver.archivedDataWithRootObject(userInfo)
// Create and register an offline pack with the shared offline storage object.
MGLOfflineStorage.sharedOfflineStorage().addPackForRegion(region, withContext: context) { (pack, error) in
guard error == nil else {
print("The pack couldn’t be created for some reason.")
return
}
// Set the pack’s delegate (assuming self conforms to the MGLOfflinePackDelegate protocol).
pack!.delegate = self
// Start downloading.
pack!.resume()
// Retain reference to pack to work around it being lost and not sending delegate messages
self.offlinePacks.append(pack!)
}
}
func offlinePack(pack: MGLOfflinePack, progressDidChange progress: MGLOfflinePackProgress) {
let userInfo = NSKeyedUnarchiver.unarchiveObjectWithData(pack.context) as! [String: String]
let completed = progress.countOfResourcesCompleted
let expected = progress.countOfResourcesExpected
print("Offline pack “\(userInfo["name"])” has downloaded \(completed) of \(expected) resources.")
}
func offlinePack(pack: MGLOfflinePack, didReceiveError error: NSError) {
let userInfo = NSKeyedUnarchiver.unarchiveObjectWithData(pack.context) as! [String: String]
print("Offline pack “\(userInfo["name"])” received error: \(error.localizedFailureReason)")
}
func offlinePack(pack: MGLOfflinePack, didReceiveMaximumAllowedMapboxTiles maximumCount: UInt64) {
let userInfo = NSKeyedUnarchiver.unarchiveObjectWithData(pack.context) as! [String: String]
print("Offline pack “\(userInfo["name"])” reached limit of \(maximumCount) tiles.")
}
}
关于ios - 如何正确使用mapbox的新MGLOfflinePackDelegate？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/36043359/