android - How do I put generic type for Gson's TypeToken? -

edit after experimenting while, know problem is. can't put generic type inside typetoken (type type = new typetoken<customresponse<t>>(){}.gettype();). when change t pojoa, can run app fine deserialize json pojoa, not pojob , pojoc.

how put generic type typetoken? or, possible this:

if (t == pojoa) {   type type = new typetoken<customresponse<pojoa>>(){}.gettype(); } else if (t == pojob) {   type type = new typetoken<customresponse<pojob>>(){}.gettype(); } else if (t == pojoc) {   type type = new typetoken<customresponse<pojoc>>(){}.gettype(); }; 

previous question: why parsenetworkresponse return nothing when using parametrized type?

i suspect error in return (response<t>) response.success(gson.fromjson(json, typeoft), httpheaderparser.parsecacheheaders(response)); part, because print log.d("customrequest", json); on previous line. (please @ my gsonrequest)

my pojo

public class customresponse<t> {   t response;    public customresponse(t response) {     this.response = response;   }    public t getresponse() {     return response;   } } 

my custom deserializer

public class pojoadeserializer implements jsondeserializer<customresponse<pojoa>> {      @override     public customresponse<pojoa> deserialize(jsonelement json, type typeoft, jsondeserializationcontext context) throws jsonparseexception {         //some deserializing thing          return new customresponse<pojoa>();     } }  public class pojobdeserializer implements jsondeserializer<customresponse<pojob>> {      @override     public customresponse<pojob> deserialize(jsonelement json, type typeoft, jsondeserializationcontext context) throws jsonparseexception {         //some deserializing thing          return new customresponse<pojob>();     } }  public class pojocdeserializer implements jsondeserializer<customresponse<pojoc>> {      @override     public customresponse<pojoc> deserialize(jsonelement json, type typeoft, jsondeserializationcontext context) throws jsonparseexception {         //some deserializing thing          return new customresponse<pojoc>();     } } 

my gsonrequest

public class customrequest<t> extends jsonrequest<t> {      private final gson gson;     private final type typeoft     private final response.listener<t> listener;      public customrequest(int method,                          string url,                          type typeoft,                          jsonobject params,                          response.listener<t> listener,                          response.errorlistener errorlistener) {          super(method, url, params.tostring(), listener, errorlistener);         this.typeoft = typeoft;         this.listener = listener;          gsonbuilder gsonbuilder = new gsonbuilder();         gsonbuilder.registertypeadapter(new typetoken<customresponse<pojoa>>(){}.gettype(), new pojoadeserializer());         gsonbuilder.registertypeadapter(new typetoken<customresponse<pojob>>(){}.gettype(), new pojobdeserializer());         gsonbuilder.registertypeadapter(new typetoken<customresponse<pojoc>>(){}.gettype(), new pojocdeserializer());         this.gson = gsonbuilder.create();     }          @override     protected void deliverresponse(t response) {         listener.onresponse(response);     }      @override     protected response<t> parsenetworkresponse(networkresponse response) {         try {             string json = new string(response.data, httpheaderparser.parsecharset(response.headers));             log.d("customrequest", json);              return (response<t>) response.success(gson.fromjson(json, typeoft), httpheaderparser.parsecacheheaders(response));         } catch (unsupportedencodingexception e) {             return response.error(new parseerror(e));         } catch (jsonsyntaxexception e) {             return response.error(new parseerror(e));         }     } } 

the actual calling

public <t> void get(string url,                     response.listener<customresponse<t>> listener,                     response.errorlistener errorlistener) {    type type = new typetoken<customresponse<t>>(){}.gettype();   customrequest<customresponse<t>> request = new customrequest<>(request.method.get, url, type, null, listener, errorlistener);   volley.newrequestqueue(context.getapplicationcontext()).add(request); }   public void getresponse() {   string url = //some url;    get(url, new response.listener<customresponse<pojoa>>() {     @override     public void onresponse(customresponse<pojoa> response) {       //do     }   }, new response.errorlistener() {     @override     public void onerrorresponse(volleyerror error) {       //do     }   }); } 

i can print log.d("customrequest", json);

so means json response fine.

the problem return (response<t>) response.success(gson.fromjson(json, typeoft), httpheaderparser.parsecacheheaders(response));.

is error when casting (response<t>).

or error on gson.fromjson(json, typeoft)

you have specify type explicitly. there's type erasure in java, means @ runtime instances of t replaced object.

you should either write 3 different deserializers different response types(pojoa, pojob, pojoc) or write generic one. should work:

public class genericconverter implements jsondeserializer<customresponse<?>> {     private type typeofresponse;      public genericconverter(type typeofresponse) {         this.typeofresponse = typeofresponse;     }      public customresponse deserialize(jsonelement json, type typeoft, jsondeserializationcontext ctx) {         customresponse response = new customresponse();         response.setresponse(ctx.deserialize(json.getasjsonobject().get("response"), typeofresponse));         return response;     } } 

and register appropriately:

gsonbuilder.registertypeadapter(new typetoken<customresponse<pojoa>>(){}.gettype(),         new genericconverter(pojoa.class)); gsonbuilder.registertypeadapter(new typetoken<customresponse<pojob>>(){}.gettype(),         new genericconverter(pojob.class)); gsonbuilder.registertypeadapter(new typetoken<customresponse<pojoc>>(){}.gettype(),         new genericconverter(pojoc.class));