Recyclerview + JSON + Fragment + Android

Question

我试图传递一个带有从JSON获得的对象的Arraylist，然后传递给Android Studio中的另一个片段。

这是我要接收数组的类

   @Override
    public View onCreateView(LayoutInflater inflater,
                             ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_car, container, false);

        new AsyncTaskParseJson().execute();



        mRecyclerView = (RecyclerView) view.findViewById(R.id.rv_list);
        mRecyclerView.setHasFixedSize(true);
        mRecyclerView.addOnItemTouchListener(new RecyclerViewTouchListener( getActivity(), mRecyclerView, this ));

        LinearLayoutManager llm = new LinearLayoutManager(getActivity());
        llm.setOrientation(LinearLayoutManager.VERTICAL);
        mRecyclerView.setLayoutManager(llm);

        CarAdapter adapter = new CarAdapter(getActivity(), mList);
        mRecyclerView.setAdapter( adapter );

        return view;
    }

那是我创建数组的类：

   public class AsyncTaskParseJson extends AsyncTask<String, String, String> {

        final String TAG = "AsyncTaskParseJson.java";
        String yourJsonStringUrl = "http://marciowelben.servidorturbo.net/getjson.php";
        JSONArray dataJsonArr = null;

        @Override
        protected void onPreExecute() {}

        @Override
        protected String doInBackground(String... arg0) {

            try {
                JsonParser jParser = new JsonParser();
                JSONObject json = jParser.getJSONFromUrl(yourJsonStringUrl);
                dataJsonArr = json.getJSONArray("emp_info");
                for (int i = 0; i < dataJsonArr.length(); i++) {

                    JSONObject c = dataJsonArr.getJSONObject(i);

                    // Storing each json item in variable
                    String firstname = c.getString("employee name");
                    String lastname = c.getString("employee no");

                    Car d = new Car(firstname, lastname, R.mipmap.ic_launcher );
                    listAux.add(d);
                }

            } catch (JSONException e) {
                e.printStackTrace();
            }
            mList = listAux;
            return null;
        }
    }

所以我只想用这个数组填充我的Recyclerview。

Answer 1

由于您是在等待数据返回之前首先添加适配器，因此必须在解析完成后调用notifyDataSetChanged()以便适配器重新绘制列表。 完成此操作的另一种方法是等待结果返回，然后设置适配器。 见下文

public class MainActivity extends AppCompatActivity {
 private static final String TAG = "RecyclerViewExample";

    private List<FeedItem> feedItemList = new ArrayList<FeedItem>();

    private RecyclerView mRecyclerView;

    private MyRecyclerAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        /* Initialize recyclerview */
        mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));

        /*Downloading data from below url*/
        final String url = "http://javatechig.com/api/get_category_posts/?dev=1&slug=android";
        new AsyncHttpTask().execute(url);
    }

    public class AsyncHttpTask extends AsyncTask<String, Void, Integer> {

        @Override
        protected void onPreExecute() {
            setProgressBarIndeterminateVisibility(true);
        }

        @Override
        protected Integer doInBackground(String... params) {
            InputStream inputStream = null;
            Integer result = 0;
            HttpURLConnection urlConnection = null;

            try {
                /* forming th java.net.URL object */
                URL url = new URL(params[0]);

                urlConnection = (HttpURLConnection) url.openConnection();

                /* for Get request */
                urlConnection.setRequestMethod("GET");

                int statusCode = urlConnection.getResponseCode();

                /* 200 represents HTTP OK */
                if (statusCode ==  200) {

                    BufferedReader r = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
                    StringBuilder response = new StringBuilder();
                    String line;
                    while ((line = r.readLine()) != null) {
                        response.append(line);
                    }

                    parseResult(response.toString());
                    result = 1; // Successful
                }else{
                    result = 0; //"Failed to fetch data!";
                }

            } catch (Exception e) {
                Log.d(TAG, e.getLocalizedMessage());
            }

            return result; //"Failed to fetch data!";
        }

        @Override
        protected void onPostExecute(Integer result) {

            setProgressBarIndeterminateVisibility(false);

            /* Download complete. Lets update UI */
            if (result == 1) {
                adapter = new MyRecyclerAdapter(MainActivity.this, feedItemList);
                mRecyclerView.setAdapter(adapter);
            } else {
                Log.e(TAG, "Failed to fetch data!");
            }
        }
    }

    private void parseResult(String result) {
        try {
            JSONObject response = new JSONObject(result);
            JSONArray posts = response.optJSONArray("posts");

            /*Initialize array if null*/
            if (null == feedItemList) {
                feedItemList = new ArrayList<FeedItem>();
            }

            for (int i = 0; i < posts.length(); i++) {
                JSONObject post = posts.optJSONObject(i);

                FeedItem item = new FeedItem();
                item.setTitle(post.optString("title"));
                item.setThumbnail(post.optString("thumbnail"));
                feedItemList.add(item);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

}

Answer 2

1.Design Recycleview in layout
  <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingTop="10dp"
        android:layout_weight="1"
        />
2.add dependency in gradle.build
 compile 'com.android.support:recyclerview-v7:23.1.1'

3.Write the code in Activity

public class DoctorInformationActivity extends AppCompatActivity {

    String URL="YOUR URL";

    JSONArray Cities=null;

    ArrayList<DocotorInformation> doctorList =new ArrayList<DocotorInformation>();
    Sqlitedatabase sql;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.doctor_information_listview);
        sql=new Sqlitedatabase(getApplicationContext());
        ConnectivityManager connectivityManager
                = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
        if(activeNetworkInfo != null && activeNetworkInfo.isConnected())
        {
            Toast.makeText(getApplicationContext()," connect",Toast.LENGTH_LONG).show();
            new JSONAsyncTask().execute();
        }
        else
        {
            ArrayList<DocotorInformation> listdata=sql.getAllContacts();
            doctorList=listdata;
            RecyclerView  recyclerView = (RecyclerView) findViewById(R.id.recycler_view);


            DoctorAdapter mAdapter = new DoctorAdapter(getApplicationContext(), doctorList);
            recyclerView.setAdapter(mAdapter);
            recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));

            Toast.makeText(getApplicationContext(),"Not connect",Toast.LENGTH_LONG).show();
        }


    }

    private class JSONAsyncTask extends AsyncTask<String, Void, JSONArray> {

        private ProgressDialog dialog = new ProgressDialog(DoctorInformationActivity.this);

        @Override
        protected void onPreExecute() {
            this.dialog.setMessage("Please wait");
            this.dialog.show();
        }

        @Override
        protected JSONArray doInBackground(String... urls) {
            try {

                //------------------>>
                HttpGet httppost = new HttpGet(URL);
                HttpClient httpclient = new DefaultHttpClient();
                HttpResponse response = httpclient.execute(httppost);

                // StatusLine stat = response.getStatusLine();
                int status = response.getStatusLine().getStatusCode();

                if (status == 200) {
                    HttpEntity entity = response.getEntity();
                    String data = EntityUtils.toString(entity);


                    JSONObject jsono = new JSONObject(data);
                    Cities = jsono.getJSONArray("SearchDoctorsData");
                    return Cities;
                }


            } catch (IOException e) {
                e.printStackTrace();
            } catch (JSONException e) {

                e.printStackTrace();
            }
            return Cities;
        }

        protected void onPostExecute(JSONArray result) {
            dialog.dismiss();
            System.out.println(result);

            for (int i = 0; i < result.length(); i++) {
                JSONObject c = null;
                try {
                    DocotorInformation doc=new DocotorInformation();
                    c = result.getJSONObject(i);
                    doc.setName(c.getString("DoctorName"));
                    doc.setNumber(c.getString("Mobile"));
                    doctorList.add(doc);

                    sql.insertData(doc);
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }

            RecyclerView  recyclerView = (RecyclerView) findViewById(R.id.recycler_view);


        DoctorAdapter mAdapter = new DoctorAdapter(getApplicationContext(), doctorList);
        recyclerView.setAdapter(mAdapter);
        recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));


    }
}
}


public class DoctorAdapter extends RecyclerView.Adapter<DoctorAdapter.ViewHolder> {
private ArrayList<DocotorInformation> countries;
Context con;
public DoctorAdapter(Context c ,ArrayList<DocotorInformation> countries) {
    this.con=c;
        this.countries = countries;
        }

@Override
public DoctorAdapter.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.doctor_textviews, viewGroup, false);
        return new ViewHolder(view);
        }

@Override
public void onBindViewHolder(DoctorAdapter.ViewHolder viewHolder, int i) {
    viewHolder.name.setText(countries.get(i).getName());
        viewHolder.number.setText(countries.get(i).getNumber());
        }

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

public class ViewHolder extends RecyclerView.ViewHolder{
    private TextView name,number;
    public ViewHolder(View view) {
        super(view);

        name = (TextView)view.findViewById(R.id.name);
        number = (TextView)view.findViewById(R.id.numebr);
    }
}

}