MainActivity.java

        String url = "http://feetback-api.yourivanmill.nl/api/videos";
        Request request = new Request.Builder()
                .url(url)
                .header("Authorization", String.format("Bearer %s", token))
                .build();

        OkHttpClient client = new OkHttpClient();
        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {

            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                try {
                    JSONObject body = new JSONObject(response.body().string());
                    JSONArray videos = body.getJSONObject("success").getJSONArray("videos");

                    // Videos
                    for (int i = 0; i < videos.length(); i++) {
                        JSONObject video = videos.getJSONObject(i);
                        JSONArray drawings = video.getJSONArray("drawings");

                        List<Drawing> drawingList = new ArrayList<>();

                        // Drawings
                        for (int j = 0; j < drawings.length(); j++) {
                            JSONObject drawing = drawings.getJSONObject(j);
                            JSONArray feedback = drawing.getJSONArray("feedback");

                            List<Feedback> feedbackList = new ArrayList<>();

                            // Feedback
                            for (int k = 0; k < feedback.length(); k++) {
                                String description = feedback.getJSONObject(k).getString("description");

                                feedbackList.add(new Feedback(description));
                            }

                            drawingList.add(new Drawing(drawing.getString("time_start"), drawing.getString("time_end"), feedbackList));
                        }

                        mVideos.add(new Video(video.getInt("id"), video.getString("name"), video.getString("url"), drawingList));
                    }
                } catch (JSONException e) {
                    Log.d(TAG, "Something when wrong parsing json");
                    Log.d(TAG, e.getMessage());
                }

                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Log.d(TAG, "Received videos");

                        adapter.notifyDataSetChanged();
                    }
                });
            }
        });