Swift Google map - 加载区域设置图 block

Question

我正在使用 Swift 和 Google map ，并在我的文档目录中保存了一些用于叠加在 Zoom/lat/lng.png 结构中的图 block (例如 file:///....documents/3/2/3. .png)

 let urls: GMSTileURLConstructor = {(x, y, zoom) in
        let url = "\(documentsUrl)\(zoom)/\(x)/\(y).png"
        return URL(string: url)
 }
 layer = GMSURLTileLayer(urlConstructor: urls)
 ...

该代码片段适用于在线层，没有任何问题。但是当 filesUrl 是我的本地目录时，我收到

Task .<1> load failed with error Error Domain=NSURLErrorDomain Code=-1100 "The requested URL was not found on this server." UserInfo={NSLocalizedDescription=The requested URL was not found on this server., NSErrorFailingURLStringKey=file:///.........../Documents/7/65/42.png

是否有机会使用 Swift + Google map 获得离线图 block ？

非常感谢卡尔斯蒂

Answer 1

只需使用您自己的类并覆盖tileFor-function

class OfflineTileLayer: GMSSyncTileLayer {
    override func tileFor(x: UInt, y: UInt, zoom: UInt) -> UIImage? {

        let documentsUrl =  FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!

        let reqPath = URL(string: "\(documentsUrl)\(zoom)/\(x)/\(y).png")!.path
        print (reqPath)
        if FileManager.default.fileExists(atPath: reqPath) {
            print ("> IS ACTIVE!")
            let url = NSURL(string: reqPath)
            let data = NSData(contentsOf: url! as URL)
            return UIImage(data: data! as Data)
        }

        return kGMSTileLayerNoTile
    }
}

并从 map 初始化函数中调用它

 offlineLayer = OfflineTileLayer()
 offlineLayer.map = yourGoogleMap