在Android上使用GSON解析JSON数据

Question

I am trying to use the Gson to parse the following JSON data:

[
  {
    "idRed":1,
    "nombre":"XXXX",
    "imagen":"XXXXX.png",
    "imagenPublica":"XXXXX.png",
    "grupos":[
      {
        "idGrupo":-1,
        "nombre":"Todos"
      },
      {
        "idGrupo":1,
        "nombre":"Principal"
      }
    ]
  },
  ...
]

I have two entities to encapsulate the JSON data:

public class Red implements Parcelable {
    @SerializedName("idRed")
    private long idRed = 0; 
    @SerializedName("nombre")
    private String nombre = ""; 
    @SerializedName("imagen")
    private String url = "";    
    @SerializedName("grupos")
    private ArrayList<Grupo> grupos = new ArrayList<Grupo>();

    //getters and setters
}

And:

public class Grupo implements Parcelable {  
    @SerializedName("idGrupo")
    private long idGrupo = 0;        
    @SerializedName("idRed")
    private long idRed = 0;
    @SerializedName("nombre")
    private String nombre = null;

    //getters and setters
}

And finally I have this code to parse the JSON data:

Gson gson = new Gson();
List<Red> redes = (List<Red>) gson.fromJson(result, new TypeToken<List<Red>>() {}.getType()); 

I can see my JSON in variable result , but the program throws an exception.

Can you see any bugs in my code?

Answer 1

First: Add a root to your json. You can do it by string operation after you've fetched this json by post/get.

{
result: [
  {
      "idRed":1,
      "nombre":"XXXX",
      "imagen":"XXXXX.png",
      "imagenPublica":"XXXXX.png",
      "grupos":[
         {
            "idGrupo":-1,
            "nombre":"Todos"
         },
         {
            "idGrupo":1,
            "nombre":"Principal"
         }
       ]
  },
  ...
]
}

Add a new class for root, the rest classes could still be used.

public class Result implements Parcelable {
    @SerializedName("result")
    private ArrayList<Red> grupos = new ArrayList<Red>();
}