我想用一個片段實現我的recyclerview使用asynctask

Question

我的代碼實際上是從一個活動的recyclerview，現在我希望它在一個片段上實現..但是當它將啓動主要的片段應用程序崩潰..是它使用這些相同類型的代碼可以這樣做嗎？

主要碎片

public class MainFragment extends Fragment { 


public MainFragment() { 
    // Required empty public constructor 
} 




@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    // Inflate the layout for this fragment 

    BackgroundTask backgroundTask = new BackgroundTask(getActivity()); 
    backgroundTask.execute(); 
    return inflater.inflate(R.layout.main_fragment_layout, container, false); 
} 

BackgroundTask.java

public class BackgroundTask extends AsyncTask<Void, Products, Void> { 
Context ctx; 
Activity activity; 
RecyclerView recyclerView; 
RecyclerView.Adapter adapter; 
RecyclerView.LayoutManager layoutManager; 
ArrayList<Products> arrayList = new ArrayList<>(); 
public BackgroundTask(Context ctx){ 
    this.ctx = ctx; 
    activity = (Activity)ctx; 
} 
String json_string="http://192.168.0.18/project/json_get_data.php"; 
@Override 
protected void onPreExecute() { 
    recyclerView = (RecyclerView)activity.findViewById(R.id.recycleView); 
    layoutManager = new LinearLayoutManager(ctx); 
    recyclerView.setLayoutManager(layoutManager); 
    recyclerView.setHasFixedSize(true); 
    adapter = new RecyclerAdapter(arrayList); 
    recyclerView.setAdapter(adapter); 

} 

@Override 
protected Void doInBackground(Void... params) { 
    try { 
     URL url = new URL(json_string); 
     HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection(); 
     InputStream inputStream = httpURLConnection.getInputStream(); 
     BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream)); 
     StringBuilder stringBuilder = new StringBuilder(); 
     String line; 
     while ((line = bufferedReader.readLine())!= null){ 
      stringBuilder.append(line + "\n"); 
     } 
     httpURLConnection.disconnect(); 
     String json_string = stringBuilder.toString().trim(); 
     JSONObject jsonObject = new JSONObject(json_string); 
     JSONArray jsonArray = jsonObject.getJSONArray("server_response"); 
     int count = 0; 
     while (count<jsonArray.length()){ 
      JSONObject JO = jsonArray.getJSONObject(count); 
      count++; 
      Products products = new Products(JO.getString("name"), JO.getString("type"),JO.getString("price")); 
      publishProgress(products); 
     } 
     Log.d("JSON_STRING", json_string); 

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


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

    return null; 
} 

@Override 
protected void onProgressUpdate(Products... values) { 
    arrayList.add(values[0]); 
    adapter.notifyDataSetChanged(); 
} 

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

預先感謝您..

Answer 1

更清晰的答案是轉讓本線：

BackgroundTask backgroundTask = new BackgroundTask(getActivity()); 
backgroundTask.execute(); 

到onStart（）在y中我們期望的片段