OKHTTP

public class OKHttpHelper {

    private static final String TAG = "OKHttp";

    private static final String BASE_URL = "http://api.douban.com";
    private static final String MOVIE_URL = "/v2/movie/top250";
    private static final String SUB_URL = "/v2/movie/subject/";
    private static final String API_KEY = "?apikey=0b2bdeda43b5688921839c8ecb20399b";

    private Context mContext;
    private int mCount = 0;
    private int mTotal = 0;
    private HashMap<String, Integer> mMovieMap = new HashMap<>();
    private ArrayList<ImgLoader> mImgList = new ArrayList<>();
    private CountDownLatch mCountLatch;

    private OkHttpClient client = new OkHttpClient();

    public OKHttpHelper(Context context) {
        mContext = context;
    }

    public void request() {
        final Request request = new Request.Builder().url(BASE_URL + MOVIE_URL + API_KEY).build();
        client.newCall(request).enqueue(new MainCallback());
    }

    public void request(int id) {
        final Request request = new Request.Builder().url(BASE_URL + SUB_URL + id + API_KEY).build();
        client.newCall(request).enqueue(new MainCallback());
    }

    private void loadImg(String title, String url) {
        final Request request = new Request.Builder().url(url).build();
        client.newCall(request).enqueue(new ImgCallback(title));
    }

    private void parseJson(String content) throws JSONException {
        JSONObject jsonObject = new JSONObject(content);
        String count = jsonObject.getString("count");
        String total = jsonObject.getString("total");
        JSONArray subArray = jsonObject.getJSONArray("subjects");
        for (int j = 0; j < subArray.length(); j++) {
            JSONObject subjects = subArray.getJSONObject(j);
            String title = subjects.getString("title");
            String idStr = subjects.getString("id");
            JSONObject images = subjects.getJSONObject("images");
            String imgUrl = images.getString("large");
            if (idStr != null) {
                int id = Integer.parseInt(idStr);
                mMovieMap.put(title, id);
            }
            if (imgUrl != null) {
                loadImg(title, imgUrl);
            }
        }
        if (count != null) {
            mCount = Integer.parseInt(count);
            mCountLatch = new CountDownLatch(mCount);
            new Thread(new WaitJob()).start();
        }
        if (total != null) {
            mTotal = Integer.parseInt(total);
        }
        Log.d(TAG, "parseJson " + mTotal + " " + mCount);
        mMovieMap.entrySet().forEach(e->Log.d(TAG, "title " + e.getKey() + " id " + e.getValue()));
    }

    private class MainCallback implements Callback {

        @Override
        public void onFailure(Request request, IOException e) {
            Log.d(TAG, "onFailure");
        }

        @Override
        public void onResponse(Response response) throws IOException {
            String content = response.body().string();
            Log.d(TAG, "onResponse " + content);
            try {
                parseJson(content);
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
    }

    private class WaitJob implements Runnable {

        @Override
        public void run() {
            Log.d(TAG, "waiting for count down");
            if (mCountLatch != null) {
                try {
                    mCountLatch.await();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            Intent intent = new Intent(mContext, MovieActivity.class);
            intent.putParcelableArrayListExtra("data", mImgList);
            mContext.startActivity(intent);
        }
    }

    private class ImgCallback implements Callback {

        private String title;

        public ImgCallback(String name) {
            title = name;
        }

        @Override
        public void onFailure(Request request, IOException e) {
            Log.d(TAG, "onFailure");
        }

        @Override
        public void onResponse(Response response) throws IOException {
            byte [] data = response.body().bytes();
            ImgLoader imgLoader = new ImgLoader(title, data);
            mImgList.add(imgLoader);
            mCountLatch.countDown();
        }
    }
}

AsyncTask

public class LoadTask extends AsyncTask {

    private static final String TAG = "LoadTask";
    private Context context;

    public LoadTask(Context context) {
        this.context = context;
    }
    @Override
    protected Object doInBackground(Object[] objects) {
        Log.d(TAG, "OKHttpHelper");
        new OKHttpHelper(context).request();
        return null;
    }
}

RecyclerView

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {

    private static final String TAG = "RecyclerAdapter";
    private List<ImgLoader> mImgList;

    public RecyclerAdapter(List<ImgLoader> list) {
        mImgList = list;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        Log.d(TAG, "onCreateViewHolder");
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_layout,
                parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        ImgLoader loader = mImgList.get(position);
        Glide.with(holder.itemView).load(loader.data).into(holder.imageView);
        holder.textView.setText(loader.name);
    }

    @Override
    public int getItemCount() {
        return mImgList.size();
    }

    public static class ViewHolder extends RecyclerView.ViewHolder {

        ImageView imageView;
        TextView textView;

        public ViewHolder(View itemView) {
            super(itemView);
            imageView = itemView.findViewById(R.id.img);
            textView = itemView.findViewById(R.id.text);
        }
    }
}

Parcel

public class ImgLoader implements Parcelable {

    public String name;
    public byte[] data;

    public ImgLoader(String name, byte[] data) {
        this.name = name;
        this.data = data;
    }

    protected ImgLoader(Parcel in) {
        name = in.readString();
        data = in.readBlob();
    }

    public static final Creator<ImgLoader> CREATOR = new Creator<ImgLoader>() {
        @Override
        public ImgLoader createFromParcel(Parcel in) {
            return new ImgLoader(in);
        }

        @Override
        public ImgLoader[] newArray(int size) {
            return new ImgLoader[size];
        }
    };

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(name);
        dest.writeBlob(data);
    }
}

参考:

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