java - 深入研究 Android JSON 数据数组

Question

我在尝试进一步深入了解 json 数据以提取特定的键/值对时遇到问题。我只是想拉出经度/纬度，我认为它是位置的子数组，它是几何的子数组。我的 JSON:

results": [
    {
      "address_components": [
        {
          "long_name": "56",
          "short_name": "56",
          "types": [
            "street_number"
          ]
        },
        {
          "long_name": "Rosario Drive",
          "short_name": "Rosario Dr",
          "types": [
            "route"
          ]
        },
        {
          "long_name": "Waterbury",
          "short_name": "Waterbury",
          "types": [
            "locality",
            "political"
          ]
        },
        {
          "long_name": "New Haven",
          "short_name": "New Haven",
          "types": [
            "administrative_area_level_2",
            "political"
          ]
        },
        {
          "long_name": "Connecticut",
          "short_name": "CT",
          "types": [
            "administrative_area_level_1",
            "political"
          ]
        },
        {
          "long_name": "United States",
          "short_name": "US",
          "types": [
            "country",
            "political"
          ]
        },
        {
          "long_name": "06708",
          "short_name": "06708",
          "types": [
            "postal_code"
          ]
        }
      ],
      "formatted_address": "56 Rosario Drive, Waterbury, CT 06708, USA",
      "geometry": {
        "bounds": {
          "northeast": {
            "lat": 41.5291983,
            "lng": -73.0523455
          },
          "southwest": {
            "lat": 41.5291845,
            "lng": -73.0523456
          }
        },
        "location": {
          "lat": 41.5291845,
          "lng": -73.0523456
        },
        "location_type": "RANGE_INTERPOLATED",
        "viewport": {
          "northeast": {
            "lat": 41.5305403802915,
            "lng": -73.05099656970849
          },
          "southwest": {
            "lat": 41.5278424197085,
            "lng": -73.05369453029151
          }
        }
      },
      "types": [
        "street_address"
      ]
    },
    {
      "address_components": [
        {
          "long_name": "56",
          "short_name": "56",
          "types": [
            "street_number"
          ]
        },
        {
          "long_name": "Rosario Drive",
          "short_name": "Rosario Dr",
          "types": [
            "route"
          ]
        },
        {
          "long_name": "Woodbridge",
          "short_name": "Woodbridge",
          "types": [
            "sublocality",
            "political"
          ]
        },
        {
          "long_name": "Vaughan",
          "short_name": "Vaughan",
          "types": [
            "locality",
            "political"
          ]
        },
        {
          "long_name": "York Regional Municipality",
          "short_name": "York Regional Municipality",
          "types": [
            "administrative_area_level_2",
            "political"
          ]
        },
        {
          "long_name": "Ontario",
          "short_name": "ON",
          "types": [
            "administrative_area_level_1",
            "political"
          ]
        },
        {
          "long_name": "Canada",
          "short_name": "CA",
          "types": [
            "country",
            "political"
          ]
        },
        {
          "long_name": "L4H",
          "short_name": "L4H",
          "types": [
            "postal_code_prefix",
            "postal_code"
          ]
        }
      ],
      "formatted_address": "56 Rosario Drive, Vaughan, ON L4H, Canada",
      "geometry": {
        "bounds": {
          "northeast": {
            "lat": 43.8324404,
            "lng": -79.5703888
          },
          "southwest": {
            "lat": 43.83244029999999,
            "lng": -79.5704073
          }
        },
        "location": {
          "lat": 43.8324404,
          "lng": -79.5704073
        },
        "location_type": "RANGE_INTERPOLATED",
        "viewport": {
          "northeast": {
            "lat": 43.83378933029149,
            "lng": -79.5690490697085
          },
          "southwest": {
            "lat": 43.8310913697085,
            "lng": -79.57174703029152
          }
        }
      },
      "types": [
        "street_address"
      ]
    },
    {
      "address_components": [
        {
          "long_name": "56",
          "short_name": "56",
          "types": [
            "street_number"
          ]
        },
        {
          "long_name": "Rosario Drive",
          "short_name": "Rosario Dr",
          "types": [
            "route"
          ]
        },
        {
          "long_name": "Summerville",
          "short_name": "Summerville",
          "types": [
            "locality",
            "political"
          ]
        },
        {
          "long_name": "Dorchester",
          "short_name": "Dorchester",
          "types": [
            "administrative_area_level_2",
            "political"
          ]
        },
        {
          "long_name": "South Carolina",
          "short_name": "SC",
          "types": [
            "administrative_area_level_1",
            "political"
          ]
        },
        {
          "long_name": "United States",
          "short_name": "US",
          "types": [
            "country",
            "political"
          ]
        },
        {
          "long_name": "29483",
          "short_name": "29483",
          "types": [
            "postal_code"
          ]
        }
      ],
      "formatted_address": "56 Rosario Drive, Summerville, SC 29483, USA",
      "geometry": {
        "bounds": {
          "northeast": {
            "lat": 33.0303119,
            "lng": -80.2500213
          },
          "southwest": {
            "lat": 33.0302964,
            "lng": -80.2500223
          }
        },
        "location": {
          "lat": 33.0302964,
          "lng": -80.2500213
        },
        "location_type": "RANGE_INTERPOLATED",
        "viewport": {
          "northeast": {
            "lat": 33.0316531302915,
            "lng": -80.24867281970849
          },
          "southwest": {
            "lat": 33.0289551697085,
            "lng": -80.25137078029151
          }
        }
      },
      "partial_match": true,
      "types": [
        "street_address"
      ]
    },
    {
      "address_components": [
        {
          "long_name": "56",
          "short_name": "56",
          "types": [
            "street_number"
          ]
        },
        {
          "long_name": "Rosario Drive",
          "short_name": "Rosario Dr",
          "types": [
            "route"
          ]
        },
        {
          "long_name": "Silver Lake",
          "short_name": "Silver Lake",
          "types": [
            "neighborhood",
            "political"
          ]
        },
        {
          "long_name": "Providence",
          "short_name": "Providence",
          "types": [
            "locality",
            "political"
          ]
        },
        {
          "long_name": "Providence",
          "short_name": "Providence",
          "types": [
            "administrative_area_level_2",
            "political"
          ]
        },
        {
          "long_name": "Rhode Island",
          "short_name": "RI",
          "types": [
            "administrative_area_level_1",
            "political"
          ]
        },
        {
          "long_name": "United States",
          "short_name": "US",
          "types": [
            "country",
            "political"
          ]
        },
        {
          "long_name": "02909",
          "short_name": "02909",
          "types": [
            "postal_code"
          ]
        }
      ],
      "formatted_address": "56 Rosario Drive, Providence, RI 02909, USA",
      "geometry": {
        "bounds": {
          "northeast": {
            "lat": 41.8053438,
            "lng": -71.4620833
          },
          "southwest": {
            "lat": 41.8053382,
            "lng": -71.4621001
          }
        },
        "location": {
          "lat": 41.8053382,
          "lng": -71.4620833
        },
        "location_type": "RANGE_INTERPOLATED",
        "viewport": {
          "northeast": {
            "lat": 41.8066899802915,
            "lng": -71.46074271970849
          },
          "southwest": {
            "lat": 41.8039920197085,
            "lng": -71.46344068029151
          }
        }
      },
      "partial_match": true,
      "types": [
        "street_address"
      ]
    }
  ],
  "status": "OK"
}

我的代码:

if (response != null)
            {
                JSONObject json;
                try {
                    json = new JSONObject(response);
                    JSONObject results = json.getJSONObject("results");
                    JSONArray geometry = results.getJSONArray("geometry");
                    JSONArray location = geometry.getJSONArray("location");




                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

            }

错误:

On this line:                   JSONArray location = geometry.getJSONArray("location");

The method getJsonArray(int) in the type JSONArray is not applicable for the arguments String.

Answer 1

JSON 响应对象的结构是:

“结果”是包含 4 个 JSONObject 的 JSONArray。

这些 JSONObject 包含其他 JSONObject，例如

"address_components", "formatted_address", "geometry" and "types"

您想要获取位于 JSOBObject“location”中的 JSONObjects“lat”和“lng”，而后者又位于 JSONObject“geometry”中。

整个结构是这样的:

• JSONArray“结果”

  • JSONObject [0]

    • JSONObject“地址组件”
    • JSONObject“formatted_address”
    • JSONObject“几何”
      • JSOBObject“位置”
        • JSOBObject“lat”<--------你想要这个
        • JSOBObject "lng"<-------- 和这个

  • JSONObject [1]

  等等

要获取纬度和经度，您可以这样做:

JSONObject json;
    try {
        //create main JSONObject
        json = new JSONObject(response);

        //get results array
        JSONArray results = json.getJSONArray("results");

        //get first JSONObjects in the array
        JSONObject firstObj = results.getJSONObject(0);

        //get JSONObject for key "geometry"
        JSONObject geometry = firstObj.getJSONObject("geometry");

        //get JSONObject for key "location"
        JSONObject location = geometry.getJSONObject("location");

        //get strings for keys "lat" and "lng"
        String lat = location.getString("lat");
        String lng = location.getString("lng");

    } catch (JSONException e) {
        e.printStackTrace();
    }

要获取剩余的纬度和经度，只需遍历数组中的所有对象即可，因此:

JSONObject firstObj = results.getJSONObject(1);
JSONObject firstObj = results.getJSONObject(2);
JSONObject firstObj = results.getJSONObject(3);

顺便说一句，您的 json 响应的开头缺少 { 和 "。我想这只是一个遗漏，但您可以检查是否有任何 JSON 字符串在 jsonlint.com 有效。