Ion-koush - 当我想获得JsonArray时出错

Question

I'm going to use Ion library in my project. An api that I'm using is like this: API link

I wrote this based on ion-sample twitter:

Future<JsonArray> VideoLoad;
    private void load(){

        String MostWatched_Url      = "http://www.aparat.com/etc/api/mostviewedvideos/perpage/20";

        // don't attempt to load more if a load is already in progress
        if (VideoLoad != null && !VideoLoad.isDone() && !VideoLoad.isCancelled()) return;

        VideoLoad = Ion.with(this, MostWatched_Url)
                .setLogging("Parsvid", Log.DEBUG)
                .asJsonArray()
                .setCallback(new FutureCallback<JsonArray>() {

                    @Override
                    public void onCompleted(Exception e, JsonArray result) {
                        for (int i = 0; i < result.size(); i++) {
                            videoAdapter.add(result.get(i).getAsJsonObject());
                        }
            }
        });
    }

But when i run this I get this error:

05-03 13:58:27.258: D/Parsvid(19020): (629 ms) http://www.aparat.com/etc/api/mostviewedvideos/perpage/20: Caching response
05-03 13:58:27.258: D/Parsvid(19020): (630 ms) http://www.aparat.com/etc/api/mostviewedvideos/perpage/20: Connection successful
05-03 13:58:27.318: D/AndroidRuntime(19020): Shutting down VM
05-03 13:58:27.318: W/dalvikvm(19020): threadid=1: thread exiting with uncaught exception (group=0x417e1c08)
05-03 13:58:27.323: D/Parsvid(19020): (691 ms) http://www.aparat.com/etc/api/mostviewedvideos/perpage/20: Recycling keep-alive socket
05-03 13:58:27.323: E/AndroidRuntime(19020): FATAL EXCEPTION: main
05-03 13:58:27.323: E/AndroidRuntime(19020): Process: com.may3am.parsvid, PID: 19020
05-03 13:58:27.323: E/AndroidRuntime(19020): java.lang.ClassCastException: com.google.gson.JsonObject cannot be cast to com.google.gson.JsonArray
05-03 13:58:27.323: E/AndroidRuntime(19020):    at com.may3am.parsvid.MainActivity$2.onCompleted(MainActivity.java:1)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at com.koushikdutta.async.future.SimpleFuture.handleCallbackUnlocked(SimpleFuture.java:96)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at com.koushikdutta.async.future.SimpleFuture.setComplete(SimpleFuture.java:130)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at com.koushikdutta.async.future.SimpleFuture.setComplete(SimpleFuture.java:117)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at com.koushikdutta.ion.IonRequestBuilder$1.run(IonRequestBuilder.java:239)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at com.koushikdutta.async.AsyncServer$RunnableWrapper.run(AsyncServer.java:53)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at android.os.Handler.handleCallback(Handler.java:733)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at android.os.Handler.dispatchMessage(Handler.java:95)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at android.os.Looper.loop(Looper.java:136)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at android.app.ActivityThread.main(ActivityThread.java:5476)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at java.lang.reflect.Method.invokeNative(Native Method)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at java.lang.reflect.Method.invoke(Method.java:515)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)
05-03 13:58:27.323: E/AndroidRuntime(19020):    at dalvik.system.NativeStart.main(Native Method)

Where is my bad?! I did it as like as ion-sample, of course my api don't need to authenticating... and i dont set header for my request.

Answer 1

What you receive is not an array, but a single object, that contains an array as a value of the attribute mostviewedvideos :

{"mostviewedvideos":[....],
 "ui":{...}}

That is what your error is saying (object can not be cast to an array). If it were an array it would have started with square brackets []

Answer 2

I agree with Boris. in JSON everything you are getting under JSONObject.

Here is a sample project to help you with. This project has the particular code for getting JSONArrays from the server and convert it to java object using GSON.

You can fork it from github and reuse the already tested code for Ion Library.

Check this out.

Hope it helps.