将长坐标字符串解析为纬度和经度 Flutter

Question

我在 Json

的 API 电话中收到 String 的经纬度和经度

"lineStrings": [
        "[[[-0.301457,51.515017],[-0.288265,51.51014],[-0.280462,51.503057],[-0.267972,51.494627],[-0.254555,51.495148],[-0.245704,51.494917],[-0.235881,51.494122],[-0.22362,51.4923],[-0.213427,51.490311],[-0.206636,51.490459],[-0.193378,51.492063],[-0.182658,51.494316],[-0.174138,51.494094],[-0.156377,51.49227],[-0.143102,51.496359],[-0.133608,51.499544],[-0.124861,51.50132],[-0.122666,51.507058],[-0.11426,51.511006],[-0.103659,51.511581],[-0.094009,51.512117],[-0.090432,51.51151],[-0.085969,51.5107],[-0.076546,51.509971],[-0.072384,51.515037],[-0.059971,51.519518],[-0.046596,51.521858],[-0.03364,51.525122],[-0.025128,51.52694],[-0.011538,51.524839],[0.005055,51.528136],[0.017451,51.531341],[0.035263,51.53534],[0.051186,51.538948],[0.081053,51.539321],[0.10153,51.538372],[0.127016,51.540331],[0.147527,51.541639],[0.166017,51.544096],[0.19864,51.549775],[0.219116,51.554093],[0.235809,51.55856],[0.250882,51.559063]]]"]

与我习惯的调用不同，它们不是作为我可以迭代的单独的纬度和经度值，它 returns 作为一个长字符串块。

我可能不正确，但我不相信我可以解析它，因为没有 lat & long class 可以迭代，只有 lineStrings是一个长块。我要解析的 Quicktype.io class 在迭代

时将我带到 .linestrings

我想将它们分成坐标对，我可以从每个坐标对中获取纬度和经度。

我试过```拆分````但是由于双打和双打之间的逗号我无法让它工作。我也试过删除特殊字符，但无法保持格式。

欢迎提出任何建议。

最终目标是能够执行如下操作

for (var x in coordinates){
GeoCoordinates y = GeoCoordinates(x.latitude, x.longitude);
}

谢谢

Answer 1

您将不得不进行一些手动拆分：

void main() {
  '[[[-0.301457,51.515017],[-0.288265,51.51014],[-0.280462,51.503057]]]'
      .split('],[')
      .forEach((p) => print(p.replaceAll('[', '').replaceAll(']', '')));
}

打印：

-0.301457,51.515017
-0.288265,51.51014
-0.280462,51.503057

您可以在 , 上进一步拆分并解析为一对双打。

或者您可以添加一个 LatLong class 来保存货币对：

void main() {
  final latLongs =
      '[[[-0.301457,51.515017],[-0.288265,51.51014],[-0.280462,51.503057]]]'
          .split('],[')
          .map((p) => LatLong.fromString(
                p.replaceAll('[', '').replaceAll(']', ''),
              ));

  print(latLongs);
}

class LatLong {
  LatLong(this.lat, this.long);

  factory LatLong.fromString(String pair) {
    final parts = pair.split(',');
    return LatLong(double.parse(parts[0]), double.parse(parts[1]));
  }

  double lat;
  double long;
}

Answer 2

var json = {"lineStrings": [
                    "[[[-0.301457,51.515017],[-0.288265,51.51014],[-0.280462,51.503057],[-0.267972,51.494627],[-0.254555,51.495148],[-0.245704,51.494917],[-0.235881,51.494122],[-0.22362,51.4923],[-0.213427,51.490311],[-0.206636,51.490459],[-0.193378,51.492063],[-0.182658,51.494316],[-0.174138,51.494094],[-0.156377,51.49227],[-0.143102,51.496359],[-0.133608,51.499544],[-0.124861,51.50132],[-0.122666,51.507058],[-0.11426,51.511006],[-0.103659,51.511581],[-0.094009,51.512117],[-0.090432,51.51151],[-0.085969,51.5107],[-0.076546,51.509971],[-0.072384,51.515037],[-0.059971,51.519518],[-0.046596,51.521858],[-0.03364,51.525122],[-0.025128,51.52694],[-0.011538,51.524839],[0.005055,51.528136],[0.017451,51.531341],[0.035263,51.53534],[0.051186,51.538948],[0.081053,51.539321],[0.10153,51.538372],[0.127016,51.540331],[0.147527,51.541639],[0.166017,51.544096],[0.19864,51.549775],[0.219116,51.554093],[0.235809,51.55856],[0.250882,51.559063]]]"
                  ]
                };


                List<dynamic> jsonList = json["lineStrings"]!
                    .first
                    .replaceAll("[", "")
                    .replaceAll("]", "")
                    .split(",");


                List<Coordinates> result = [];
                for (var i = 0; i < jsonList.length / 2; i++) {
                  result.add(Coordinates(
                      lat: double.parse(jsonList[i]),
                      long: double.parse(jsonList[i + 1])));
                }


                result.forEach((element) {
                  print("Lat" + element.lat.toString());
                  print("Long" + element.long.toString());
                  print("*************************");
                });

class Coordinates {
      double lat;
      double long;

  Coordinates({
    required this.lat,
    required this.long,
 });
 }

颤振：Lat-0.301457

颤振：Long51.515017

颤振：************************

扑动：Lat51.515017

扑动：Long-0.288265

颤振：************************

颤振：Lat-0.288265

扑动：Long51.51014

颤振：************************

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