如何遍历 JSON 坐标并将注释构建为一个函数？

Posted 2023-02-24

【中文标题】如何遍历 JSON 坐标并将注释构建为一个函数？

【英文标题】：How do I iterate through JSON co-ordinates and build annotations as one function?

【发布时间】：2016-01-27 12:45:20

【问题描述】：

我正在努力获取使用 JSON 数据放置的注释。我尝试将 JSON 中的坐标迭代到一个新数组中，但是当我尝试将一个数组传递到我需要坐标的位置时它失败了，因为它不能接受数组。我该如何解决这个问题？

谁能帮忙？

    Alamofire.request(.GET, "https://demo1991046.mockable.io/score/locations").responseJSON  (responseData) -> Void in
        let swiftyJsonVar = JSON(responseData.result.value!)

        if let resData = swiftyJsonVar["users"].arrayObject as? [NSArray] 
            self.newArray = (resData as? [NSArray])


        
       print("\([self.newArray])")






        for var i = 0; i < self.newArray!.count; ++i 



            self.longitude.append(self.newArray[i]["lon"] as! String!)
            print("longitude: \(self.longitude)")

            self.latitude.append(self.newArray[i]["lat"] as! String!)
            print("latitude: \(self.latitude)")
        

        let doubleLat = self.latitude.map 
            Double(($0 as NSString).doubleValue)
        

        let doubleLon = self.longitude.map 
            Double(($0 as NSString).doubleValue)
        

        print("doublelat: \(doubleLat)")
        print("doubleLon: \(doubleLon)")

        // 1
   self.locationManager.delegate = self
        // 2
   self.locationManager.requestAlwaysAuthorization()
        // 3
        let theSpan:MKCoordinateSpan = MKCoordinateSpanMake(0.01 , 0.01)
        let location:CLLocationCoordinate2D = CLLocationCoordinate2D(latitude: doubleLat, longitude: doubleLon) // <- here is where I get an error: "Cannot convert value of type '[Double]' to expect argument type 'CLLocationDegrees' (aka 'Double")"
        //        print("lat: \((locationManager.location?.coordinate.latitude)!)")
        //        print("lon: \((locationManager.location?.coordinate.longitude)!)")
        let theRegion:MKCoordinateRegion = MKCoordinateRegionMake(location, theSpan)

        self.mapView.setRegion(theRegion, animated: true)

        let anotation = MKPointAnnotation()
        anotation.coordinate = location
        anotation.title = "The Location"
        anotation.subtitle = "This is the location !!!"
        self.mapView.addAnnotation(anotation)

    

【问题讨论】：

从我在你的代码中看到的 doubleLat 和 doubleLon 是 [Double] 不是双倍，这就是 let location:... 行中的错误的原因

【参考方案1】：

我已经对您的代码进行了以下一些修改

未将 json 转换为 NSArray（使用 .array 而不是 .arrayObject） 已将注释添加到 for 循环内的地图以添加所有注释。 将区域设置移至 for 循环之外的地图，并留给您设置您喜欢的位置。

---

 Alamofire.request(.GET, "https://demo1991046.mockable.io/score/locations").responseJSON  (responseData) -> Void in
        let swiftyJsonVar = JSON(responseData.result.value!)
        // get the users from the json var, no need to convert it to Array
        guard let usersJsonArray = swiftyJsonVar["users"].array else 
           // users not found in the json
           return
       
        // the usersJsonArray is array of json which will be much easier for work with.
         // No need for 1,2 and 3 to be in the for loop.
         // 1
        self.locationManager.delegate = self
        // 2
        self.locationManager.requestAlwaysAuthorization()
        // 3
        let theSpan:MKCoordinateSpan = MKCoordinateSpanMake(0.01 , 0.01)

        for userJson in usersJsonArray 

            let longitudeString = userJson["lon"].stringValue
            print("longitude: \(longitudeString)")

            let latitudeString = userJson["lat"].stringValue
            print("latitude: \(latitudeString)")

           let doubleLat = Double(latitudeString)
           let doubleLon = Double(longitudeString)

           print("doublelat: \(doubleLat)")
           print("doubleLon: \(doubleLon)")

           // by having the next code block inside the for loop you will be able to add all the user locations to the map as anotations.
           let location:CLLocationCoordinate2D = CLLocationCoordinate2D(latitude: doubleLat, longitude: doubleLon) // Now should work fine

           let anotation = MKPointAnnotation()
           anotation.coordinate = location
           anotation.title = "The Location"
           anotation.subtitle = "This is the location !!!"
           self.mapView.addAnnotation(anotation)
     // for usersJson

    // you need to figure out the loaction you will set for the mapView region.
    let location = .... // set the location you like. 
    let theRegion:MKCoordinateRegion = MKCoordinateRegionMake(location, theSpan)
    self.mapView.setRegion(theRegion, animated: true)

【讨论】：

@AndrewWormald 欢迎您。你应该对这个问题进行任何编辑吗？我想投票，但在您进行任何编辑之前不能投票