You have to specify the type of T at the time of deserialization. How would your List of posts get created if Gson didn’t know what Type to instantiate? It can’t stay T forever. So, you would provide the type T as a Class parameter. Now assuming, the type of posts was String you would … Read more
Only the TypeToken part is neccesary (when there are Generics involved). Map<String, String> myMap = new HashMap<String, String>(); myMap.put(“one”, “hello”); myMap.put(“two”, “world”); Gson gson = new GsonBuilder().create(); String json = gson.toJson(myMap); System.out.println(json); Type typeOfHashMap = new TypeToken<Map<String, String>>() { }.getType(); Map<String, String> newMap = gson.fromJson(json, typeOfHashMap); // This type must match TypeToken System.out.println(newMap.get(“one”)); System.out.println(newMap.get(“two”)); Output: … Read more
As you note, Gson has no facility to define a “required field” and you’ll just get null in your deserialized object if something is missing in the JSON. Here’s a re-usable deserializer and annotation that will do this. The limitation is that if the POJO required a custom deserializer as-is, you’d have to go a … Read more
You need to give Gson information on the specific generic type of List you’re using (or any generic type you use with it). Particularly when deserializing JSON, it needs that information to be able to determine what type of object it should deserialize each array element to. Type listOfTestObject = new TypeToken<List<TestObject>>(){}.getType(); String s = … Read more
double result = jobj.get(“test”).getAsDouble();
The example Java data structure in the original question does not match the description of the JSON structure in the comment. The JSON is described as “an array of {object with an array of {object}}”. In terms of the types described in the question, the JSON translated into a Java data structure that would match … Read more
You can try this. import com.google.gson.annotations.SerializedName; public enum Color { @SerializedName(“0”) RED (0), @SerializedName(“1”) BLUE (1), @SerializedName(“2”) YELLOW (2); private final int value; public int getValue() { return value; } private Color(int value) { this.value = value; } }
It seems like we must request that enumerations’ members are kept. Adding this to the proguard config file worked for me: -keepclassmembers enum * { *; } Or, if you want to be more specific, -keepclassmembers enum com.your.package.** { *; }
I suspect that result1 has some characters at the end of it that you can’t see in the debugger that follow the closing } character. What’s the length of result1 versus result2? I’ll note that result2 as you’ve quoted it has 169 characters. GSON throws that particular error when there’s extra characters after the end … Read more
Alfonso’s comment: Finally I got the solution: // Creates the json object which will manage the information received GsonBuilder builder = new GsonBuilder(); // Register an adapter to manage the date types as long values builder.registerTypeAdapter(Date.class, new JsonDeserializer<Date>() { public Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException { return new Date(json.getAsJsonPrimitive().getAsLong()); } }); … Read more