implement AsyncTask in Fragment android

Question

I've an activity which output json data from as a list. But now I want to implement it in a fragment. In this fragment I want to view it as gridview. And both files works fine. but when I tried to implement AsyncTask I gets several redflags as unreachable code. Can someone help me with this please?

Edited: New

    public class SalesFragment extends Fragment {
        GridView gridView;

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View gv = inflater.inflate(R.layout.hot_sales, null);
            gridView = (GridView) gv.findViewById(R.id.grid_view);
            bindGridview();
            return gv;
        }

        public void bindGridview() {

           new MyAsyncTask(getActivity(),gridView).execute("");
        }

        class MyAsyncTask extends AsyncTask<String, String, String> {
            GridView mGridView;
            Activity mContext;
            Response response;
           public  MyAsyncTask(Activity context,GridView gview) {
             this.mGridView=gview;
             this.mContext=context;
            }

           protected String doInBackground(String... params)  {

               File file = new File( Environment.getExternalStorageDirectory().getAbsolutePath() + "/Android/data/sample.txt");
                if(file.exists()) {
                    try{
                           Reader inputStreamReader = new InputStreamReader(new FileInputStream(file));

                           Gson gson = new Gson();
                           this.response = gson.fromJson(inputStreamReader, Response.class);
                        } catch (FileNotFoundException e) {
                           e.printStackTrace();
                        } catch (@SuppressWarnings("hiding") IOException e){
                           e.printStackTrace();
                        }
                }else{
                    System.out.println("Error");
                }
                return null;
                }

           @Override
           protected void onPostExecute(String result) {

                super.onPostExecute(result);

                //List<HashMap<String,String>> aList = new ArrayList<HashMap<String,String>>();

                for(Sales sales : this.response.sales){
                    HashMap<String, String> hm = new HashMap<String,String>();

                    if (sales.getCategories1().contains("12")){
                        //hm.put("sale_title", "" + sales.getShort_title());
                        for(Shop shop : this.response.shops){
                            String image_file = new String( Environment.getExternalStorageDirectory().getAbsolutePath()
                                    + "/images/" + shop.getImage());
                            if(shop.getId().equals(sales.getShop_id())){
                                hm.put("shop_image", image_file );
                                System.out.println(shop_image);
                            }
                        }

                  if(hm.size()>0){
                        gridView.setAdapter(new ImageAdapter(MainActivity.this,R.layout.grid_layout , imgArray, titleArray));
                             }
                    }
                }



           }
        }
    }

How to call images into gridview on above image? Please help.

Borrego

Perhaps post some code? Any number of problems can cause this. – Renal

post your implemented code here............ – Leong

@ Piyush Gupta & blaffie: the code added now. I want to do the same thing as activity in fragment. – Borrego

@Borrego so means Like in SalesActivity the functions which are performed,YOu want to it Fragment? – Leong

Answer 1

There is easy step to crate asyntask within fragment

in your fragment place code on activityCreateview

new MyAsyncTask(getActivity(), mListView).execute("");

getActivity() is method to communicate with fragment and activity

in asynstak on post

context.mListView.setArrayAdapter(...........)

here is

public class SalesFragment extends Fragment {
GridView gridView;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View gv = inflater.inflate(R.layout.hot_sales, null);
       gridView = (GridView) gv.findViewById(R.id.grid_view);
        bindGridView()
        return gv;
        //return super.onCreateView(inflater, container, savedInstanceState);
    }

public void bindGridview()
{

   new MyAsyncTask(getActivity(), gridView).execute("");
}

class MyAsyncTask extends AsyncTask<String, String, String>
{
    GridView mGridView;
    Activity mContex;
   public  MyAsyncTask(Activity contex,GridView gview)
    {
     this.mGridView=gview;
     this.mContex=contex;
    }

   protected String doInBackground(String... params)
    {

       //fetch data
    }

   @Override
    protected void onPostExecute(String result) {
      {   

        for(Sales sales : this.response.sales){
            HashMap<String, String> hm = new HashMap<String,String>();

            if (sales.getCategories1().contains("12")){
                //hm.put("sale_title", "" + sales.getShort_title());
                for(Shop shop : this.response.shops){
                    String image_file = new String(        Environment.getExternalStorageDirectory().getAbsolutePath()
                            + "/images/" + shop.getImage());
                    if(shop.getId().equals(sales.getShop_id())){
                        hm.put("shop_image", image_file );
                        System.out.println(shop_image);
                    }
                }
            }
        }
               if(hm.size()>0)
              mcontext.mGridView.setAdapter(new ImageAdapter(mContext),hm);
      }

before fetching data make it model like

public class ImageModel
    {
        String title;
        String img;
    }


ArrayList<ImageModel> arrayList=new ArrayList<ImageModel>();

fill array list with required data then

mcontext.mGridView.setAdapter(new ImageAdapter(mContext),hm,arrayList);

//in image adapter

public class ImageAdapter extends ArrayAdapter<String> {

public ImageAdapter(Context context, HashMap<String, String> hm,ArrayList<ImageModel> images ) 
        {
            super(context, R.layout.activity_t);

        }
//--code
   }

use hash map in adapter and assign images with position set data and fetch value from model

Slideaction

Thanks. Your code helped for my question, but now I've new issue. How could I call 'shop_image' to a gridview? I edited my post, Please see above code. – Borrego

you can pass image or multiple images in constructor of adapter i have edited the code see above – Slideaction

it's not worked. getting redflags on mcontext and ImageAdapter. – Borrego

@Sumeetkumar @Borrego I cant use mContext.mGridView.setAdapter() there is no mGridView in mContext obviously. How should I deel with it? – Untoward

This code is great! But I am not sure its going to work without having leak memory (OOM) error, because you are using a non static inner class (which is MyAsyncTask) inside a fragment. I recommend you try static inner class and pass context, gridView to contructor using weakReference – Froh