Question

我写了一个包含recyclerview的片段，用于显示来自Internet的数据。但是，我发现getJSON方法中的public class FragmentHot extends Fragment { private Handler mHandler = new Handler(Looper.getMainLooper()) { @Override public void handleMessage(Message msg) { switch (msg.what) { case 0: refreshRecyclerView(); break; } } }; private View mView; private List<Book> mBookList = new ArrayList<>(); BookRecyclerViewAdapter mBookRecyclerViewAdapter; private void refreshRecyclerView() { mBookRecyclerViewAdapter.notifyItemRangeInserted(0, mBookList.size() - 1); } @Nullable @Override public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) { mView = inflater.inflate(R.layout.fragment_hot, container, false); initRecyclerView(); return mView; } @Override public void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); getJSON(); } private void getJSON() { new Thread(new Runnable() { @Override public void run() { URL url; InputStream inputStream = null; try { url = new URL("http://api.zhuishushenqi.com/cats/lv2/statistics"); inputStream = url.openStream(); BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream)); StringBuilder builder = new StringBuilder(); String line; while ((line = reader.readLine()) != null) { builder.append(line); } JSONObject jsonObject = new JSONObject(builder.toString()); JSONArray books = jsonObject.getJSONArray("books"); File externalFolder = Environment.getExternalStorageDirectory(); File imageTemp = new File(externalFolder.getPath() + "/Reader/temp/cover"); if (!imageTemp.exists()) { imageTemp.mkdirs(); } for (int i = 0; i < books.length(); i++) { JSONObject jsonObjectBook = books.getJSONObject(i); String id = jsonObjectBook.getString("_id"); String title = jsonObjectBook.getString("title"); String author = jsonObjectBook.getString("author"); String shortIntro = jsonObjectBook.getString("shortIntro"); String cover = jsonObjectBook.getString("cover"); cover = URLDecoder.decode(cover); String coverPath = imageTemp.getPath() + "/" + id + ".jpg"; String site = jsonObjectBook.getString("site"); int banned = jsonObjectBook.getInt("banned"); int latelyFollower = jsonObjectBook.getInt("latelyFollower"); String retentionRatio = Integer.toString(jsonObjectBook.getInt ("retentionRatio")); Book book = new Book(id, title, author, shortIntro, cover, site, banned, latelyFollower, retentionRatio); book.setCoverPath(coverPath); mBookList.add(book); } Message message = new Message(); message.what = 0; mHandler.sendMessage(message); } catch (Exception e) { e.printStackTrace(); } finally { try { inputStream.close(); } catch (IOException e) { e.printStackTrace(); } } } }).start(); } private void initRecyclerView() { RecyclerView recyclerView = mView.findViewById(R.id.fragment_hot_recycler_view); mBookRecyclerViewAdapter = new BookRecyclerViewAdapter(mBookList, getActivity()); LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity()); recyclerView.setLayoutManager(linearLayoutManager); recyclerView.setAdapter(mBookRecyclerViewAdapter); } }根本没有运行，我无法弄清楚如何处理它。

The screenshot of my debugger

<?php
return [
    'driver' => env('FCM_PROTOCOL', 'http'),
    'log_enabled' => true,

    'http' => [
        'server_key' => config('app.fcm_mode') == 'user' ? env('FCM_SERVER_KEY', 'Your FCM server key') : env('FCM_DELIVERY_SERVER_KEY', 'Your FCM server key'),
        'sender_id' => config('app.fcm_mode') == 'user' ? env('FCM_SENDER_ID', 'Your sender id') : env('FCM_DELIVERY_SENDER_ID', 'Your sender id'),
        'server_send_url' => 'https://fcm.googleapis.com/fcm/send',
        'server_group_url' => 'https://android.googleapis.com/gcm/notification',
        'timeout' => 30.0, // in second
    ],
];

Answer 1

您需要致电sendMessage

这样的事情：

Message message = new Message();
message.what = 0;
message.obj = something;
mHandler.sendMessage(message);

您应该使用AsyncTask进行此类操作。

Answer 2

用asynctask替换线程，如下所示

new AsyncTask<Void, Void, Void>(){

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            initRecyclerView();
        }

        @Override
        protected Void doInBackground(Void... voids) {

            URL url;
            InputStream inputStream = null;
            try {
                url = new URL("http://api.zhuishushenqi.com/cats/lv2/statistics");
                inputStream = url.openStream();
                BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
                StringBuilder builder = new StringBuilder();
                String line;
                while ((line = reader.readLine()) != null) {
                    builder.append(line);
                }
                JSONObject jsonObject = new JSONObject(builder.toString());
                JSONArray books = jsonObject.getJSONArray("books");
                File externalFolder = Environment.getExternalStorageDirectory();
                File imageTemp = new File(externalFolder.getPath() + "/Reader/temp/cover");
                if (!imageTemp.exists()) {
                    imageTemp.mkdirs();
                }
                for (int i = 0; i < books.length(); i++) {
                    JSONObject jsonObjectBook = books.getJSONObject(i);
                    String id = jsonObjectBook.getString("_id");
                    String title = jsonObjectBook.getString("title");
                    String author = jsonObjectBook.getString("author");
                    String shortIntro = jsonObjectBook.getString("shortIntro");
                    String cover = jsonObjectBook.getString("cover");
                    cover = URLDecoder.decode(cover);
                    String coverPath = imageTemp.getPath() + "/" +
                            id + ".jpg";
                    String site = jsonObjectBook.getString("site");
                    int banned = jsonObjectBook.getInt("banned");
                    int latelyFollower = jsonObjectBook.getInt("latelyFollower");
                    String retentionRatio = Integer.toString(jsonObjectBook.getInt
                            ("retentionRatio"));
                    Book book = new Book(id, title, author, shortIntro, cover, site, banned,
                            latelyFollower, retentionRatio);
                    book.setCoverPath(coverPath);
                    mBookList.add(book);
                }

            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return null;
        }
    }.execute();

片段中的线程无法运行

2 个答案: