java - Android与Json解析

Question

我试图让我的应用程序连接到 REST API 并从中提取数据。到目前为止我已经提取了数据。但我不知道如何解析它。我相信这就是你接下来要做的。

这里是我的代码 fragment ，它连接到我的其余 API 并获取数据。我得到的错误是 JSONArray 无法转换为 JSONObject

 if (status == 200) {
                InputStream is = conn.getInputStream();
                BufferedReader reader = new BufferedReader(new InputStreamReader(is));
                String responseString;
                StringBuilder sb = new StringBuilder();

                while ((responseString = reader.readLine()) != null) {
                    sb = sb.append(responseString);
                }
                String speciesListData = sb.toString();
                species= SpeciesJson.fromJson(speciesListData);
                Log.d(Constants.TAG, "speciesJSON: " + species);
                return true;
            }

这是我尝试解析它的地方，直到这里它都工作正常。她是我尝试解析它的那一行

species= SpeciesJson.fromJson(speciesListData);

这就是它坏了的原因

public class SpeciesJson {
    private String scientific_name, name,description;


    public SpeciesJson (JSONObject species) throws JSONException {

        this.scientific_name=species.optString("scientific_name");
        this.name=species.optString("name");
        this.description=species.optString("description");

    }
    public static ArrayList<SpeciesJson> fromJson(String photoData) throws JSONException {
        ArrayList<SpeciesJson> speciesData = new ArrayList<>();
        JSONObject data = new JSONObject(photoData);
        JSONObject photos = data.optJSONObject("name");
        JSONArray photoArray = photos.optJSONArray("name");

        for (int i = 0; i < photoArray.length(); i++) {
            JSONObject photo = (JSONObject) photoArray.get(i);
            SpeciesJson currentPhoto = new SpeciesJson(photo);
            speciesData.add(currentPhoto);
        }
        return speciesData;
    }

所以当我使用我制作的解析方法运行它时，它不起作用。

hte json 数据的示例如下，我试图在 View 中显示科学名称和名称

  {
        "id": 1,
        "scientific_name": "Platanus racemosa",
        "name": "California Sycamore",
        "description": "typically in river areas, but planted all throughout L.A",
        "type": 1
    },
    {
        "id": 2,
        "scientific_name": "Pyrus kawakamii",
        "name": "Ornamental Pear",
        "description": "native to Asia, commonly planted in L.A",
        "type": 1
    },
    {
        "id": 3,
        "scientific_name": "Liquidambar styraciflua",
        "name": "American Sweetgum",
        "description": "native to SE U.S, planted all around L.A",
        "type": 1
    },
    {
        "id": 4,
        "scientific_name": "Setophaga coronata",
        "name": "Yellow-rumped Warbler",
        "description": "native bird, spends the winter in L.A before migrating north during the summer to breed",
        "type": 2
    },
    {
        "id": 5,
        "scientific_name": "Calypte anna",
        "name": "Anna's Hummingbird",
        "description": "native bird, does not migrate. Spends the year in L.A",
        "type": 2
    },
    {
        "id": 6,
        "scientific_name": "Regulus calendula",
        "name": "Ruby-crowned Kinglet",
        "description": "native bird, spends the winter in L.A before migrating north during the summer to breed",
        "type": 2
    }
]

Answer 1

我亲爱的 friend 使用谷歌GSON库就是这样。

为了您的帮助，我让这件事变得更容易了。

创建这个类SpeciesJson.java

public class SpeciesJson {

   private String scientific_name;
   private String name;
   private String description;

public SpeciesJson() {
}

public SpeciesJson(String scientific_name,String name,String description) {
     this.scientific_name = scientific_name;
     this.name = name;
     this.description = description;
}


//And getter,setters
}

如果 SpeciesJson 是一个简单的对象，则使用它

Gson gson = new Gson();
SpeciesJson species = gson.fromJson(responseString,SpeciesJson.class);

如果 SpeciesJson 是一个 ArrayList，则使用它(它看起来像您的情况，因此请检查它，因为您的 Json 响应包含多个 SpeciesJson 对象)

Gson gson = new Gson();
ArrayList<SpeciesJson> species = new ArrayList<>();
SpeciesJson[] speciesarray = (SpeciesJson[]) gson.fromJson(responseString,SpeciesJson[].class);
Collections.addAll(species, speciesarray);

如果您想了解有关 Gson 库的更多信息，请查看此链接 https://guides.codepath.com/android/Leveraging-the-Gson-Library