How to update UI from separate AsynkTask class

Question

I have a class CDealListing from where I execute AsynkTask class which is separate class,what I want is to update UI of class CDealListing on AsynkTask class onPost method .kindly help me .....

here is code of my class CDealListing

public class CDealAppListing extends Fragment {
public static String m_DealListingURL = "http://192.166.0.110:8080/ireward/rest/json/metallica/getDealListInJSON";
public static String s_szresult = " ";
public static RecyclerView m_RecyclerView;
public static CDealAppListingAdapter m_oAdapter;
public static CDealAppDatastorage item;
public ArrayList<CDealAppDatastorage> s_oDataset;
public int[] m_n_FormImage;
public View m_Main;
public CRegistrationSessionManagement m_oSessionManagement;
public String m_szMobileNumber, m_szEncryptedPassword;
public LinearLayoutManager mLayoutManager;
public AppCompatButton m_showMore;
public ProgressBar mProgressBar;
public int m_n_DefaultRecordCount = 5;// intiallly record count is 5.
public int m_n_DeafalutLastCount = 0;//initally lastcount is 0.

public String sz_RecordCount, sz_LastCount;
//declare boolean
private CJsonsResponse m_oJsonsResponse;


@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    m_Main = inflater.inflate(R.layout.deal_app_listing, container, false);//intialize mainLayout
    new CDealDataSent().execute(m_DealListingURL);
    init();//initialize method
    implementScroll();
    return m_Main;
}

public void init() {
    mProgressBar = (ProgressBar) m_Main.findViewById(R.id.progressBar1);
    mProgressBar.setVisibility(View.GONE);

    m_showMore = (AppCompatButton) m_Main.findViewById(R.id.show_more);
    m_showMore.setBackgroundColor(Color.TRANSPARENT);
    m_showMore.setVisibility(View.GONE);
    // Getting the string array from strings.xml
    m_n_FormImage = new int[]{
            R.drawable.amazon,
            R.drawable.whatsapp,
            R.drawable.zorpia,
            R.drawable.path,
            R.drawable.app_me,
            R.drawable.evernote,
            R.drawable.app_me};

    m_RecyclerView = (RecyclerView) m_Main.findViewById(R.id.my_recycler_view);//finding id of recyclerview
    m_RecyclerView.setItemAnimator(new DefaultItemAnimator());//setting default animation to recyclerview
    m_RecyclerView.setHasFixedSize(true);//fixing size of recyclerview
    mLayoutManager = new LinearLayoutManager(getActivity());
    m_RecyclerView.setLayoutManager(mLayoutManager);//showing odata vertically to user.
    m_oSessionManagement = new CRegistrationSessionManagement(getActivity());
    HashMap<String, String> user = m_oSessionManagement.getRegistrationDetails();
    m_szEncryptedPassword = user.get(m_oSessionManagement.s_szKEY_PASSWORD);
    m_szMobileNumber = user.get(m_oSessionManagement.s_szKEY_MOBILENUMBER);

    sz_RecordCount = String.valueOf(m_n_DefaultRecordCount);// increment of record count
    sz_LastCount = String.valueOf(m_n_DeafalutLastCount);
}

public void implementScroll() {
    m_RecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
            super.onScrollStateChanged(recyclerView, newState);
            if (newState ==  RecyclerView.SCROLL_STATE_IDLE){

            }
        }

        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);
            if (dy > 0) {

                m_showMore.setVisibility(View.VISIBLE);
                m_showMore.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        //change boolean value
                        m_showMore.setVisibility(View.GONE);
                        m_n_DefaultRecordCount = m_n_DefaultRecordCount + 5;
                        m_n_DeafalutLastCount = m_n_DeafalutLastCount + 5;

                        sz_RecordCount = String.valueOf(m_n_DefaultRecordCount);
                        sz_LastCount = String.valueOf(m_n_DeafalutLastCount);
                        new DealNext().execute(m_DealListingURL);
                    }
                });
            } else {
                m_showMore.setVisibility(View.GONE);
            }
        }
    });
}
//sending deal data to retreive response from server
public String DealListing(String url, CRegistrationDataStorage login) {
    InputStream inputStream = null;
    m_oJsonsResponse = new CJsonsResponse();
    try {
        // 1. create HttpClient
        HttpClient httpclient = new DefaultHttpClient();
        // 2. make POST request to the given URL
        HttpPost httpPost = new HttpPost(url);
        String json = "";
        // 3. build jsonObject
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("agentCode", m_szMobileNumber);
        jsonObject.put("pin", m_szEncryptedPassword);
        jsonObject.put("recordcount", sz_RecordCount);
        jsonObject.put("lastcountvalue", sz_LastCount);
        //jsonObject.put("emailId", "nirajk1190@gmail.com");
        // 4. convert JSONObject to JSON to String
        json = jsonObject.toString();
        // 5. set json to StringEntity
        StringEntity se = new StringEntity(json);
        // 6. set httpPost Entity
        httpPost.setEntity(se);
        // 7. Set some headers to inform server about the type of the content
        httpPost.setHeader("Content-type", "application/json");
        // 8. Execute POST request to the given URL
        HttpResponse httpResponse = httpclient.execute(httpPost);
        HttpEntity entity = httpResponse.getEntity();
        // 9. receive response as inputStream
        inputStream = entity.getContent();
        System.out.println("InputStream....:" + inputStream.toString());
        System.out.println("Response....:" + httpResponse.toString());

        StatusLine statusLine = httpResponse.getStatusLine();
        System.out.println("statusLine......:" + statusLine.toString());
        ////Log.d("resp_body", resp_body.toString());
        int statusCode = statusLine.getStatusCode();
        // 10. convert inputstream to string
        if (statusCode == 200) {
            // 10. convert inputstream to string
            if (inputStream != null)
                s_szresult = m_oJsonsResponse.convertInputStreamToString(inputStream);
            //String resp_body =
            EntityUtils.toString(httpResponse.getEntity());
        } else
            s_szresult = "Did not work!";
    } catch (Exception e) {
        Log.d("InputStream", e.getLocalizedMessage());
    }
    System.out.println("resul.....:" + s_szresult);
    // 11. return s_szResult
    return s_szresult;
}

and here is my AsynkTask class

/   sending deal data to server and retreive response......
class CDealDataSent extends AsyncTask<String, Void, String> {
    public JSONObject m_oResponseobject;
    public ProgressDialog m_PDialog;
    public CRegistrationDataStorage oRegisterStorage;
    public CDealAppDatastorage item;

    //      @Override
    protected void onPreExecute() {
        super.onPreExecute();
        m_PDialog = new ProgressDialog(getActivity());
        m_PDialog.setMessage("Please wait while Loading Deals...");
        m_PDialog.setCancelable(false);
        m_PDialog.show();
    }
    @Override
    protected String doInBackground(String... urls) {
        return DealListing(urls[0], oRegisterStorage);// sending data to server...

    }
    // onPostExecute displays the results of the AsyncTask.
    @Override
    protected void onPostExecute(String result) {

        m_PDialog.dismiss();
        try {
            m_oResponseobject = new JSONObject(result);// getting response from server
            final JSONArray posts = m_oResponseobject.optJSONArray("dealList");

            s_oDataset = new ArrayList<CDealAppDatastorage>();
            for (int i = 0; i < posts.length(); i++) {
                JSONObject post = posts.getJSONObject(i);
                item = new CDealAppDatastorage();
                item.setM_szHeaderText(post.getString("dealname"));
                item.setM_szsubHeaderText(post.getString("dealcode"));
                item.setM_n_Image(m_n_FormImage[i]);
                s_oDataset.add(item);

            }
            getResponse();

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

    public void getResponse() throws JSONException {
        if (m_oResponseobject.getString("resultdescription").equalsIgnoreCase("Transaction Successful")) {

            m_oAdapter = new CDealAppListingAdapter(s_oDataset);//creating object of adapter and addd setting odata to adapter for use.
            m_RecyclerView.setAdapter(m_oAdapter);//adding adapter to recyclerview
        } else if (m_oResponseobject.getString("resultdescription").equalsIgnoreCase("Connection Not Available")) {
            Toast.makeText(getActivity(), "Connection not avaliable", Toast.LENGTH_SHORT).show();
        }else if (m_oResponseobject.getString("resultdescription").equalsIgnoreCase("Deal List Not Found")){
            Toast.makeText(getActivity(),"No More Deals",Toast.LENGTH_SHORT).show();
        }
        System.out.println("agentCode...." + m_szMobileNumber);
        System.out.println("password...." + m_szEncryptedPassword);
        System.out.println("record////" + sz_RecordCount);
        System.out.println("last:........" + sz_LastCount);
    }

}

In asynkTask class get Response method update UI of class CDealListing

score 0 · Answer 1 · answered Mar 18 '16 at 04:11

0

There are 3 ways

Call some method of your Fragment in onPostExecute()
Use BroadcastReceiver in onPostExecute()
use EventBus library for passing event to your Fragment.

answered Mar 18 '16 at 04:11

Rocky

268
2
3
13

score 0 · Answer 2 · edited May 23 '17 at 11:50

One way would be to declare a listener interface and pass an instance of that interface (or perhaps a Runnable) into the AsyncTask's constructor.

In your fragment code:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    ...        
    new CDealDataSent(new Runnable() {
        @Override
        public void run() {
            // perform update UI code here
        }
    }).execute(m_DealListingURL);
    ...
}

In your AsyncTask code:

class CDealDataSent extends AsyncTask<String, Void, String> {
    private final Runnable mOnPostExecuteRunnable;
    CDealDataSent(Runnable onPostExecuteRunnable) {
        mOnPostExecuteRunnable = onPostExecuteRunnable;
    }

    ...

    @Override
    protected void onPostExecute(String result) {
        ...
        if (mPostExecuteRunnable != null) {
            mPostExecuteRunnable.run();
        }
        ...
    }
}

You could also use an anonymous subclass of AsyncTask from your fragment and override onPostExecute():

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    ...        
    new CDealDataSent() {
        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result); // be sure to call super first to do normal processing
            ... // update your UI here
        }
    }.execute(m_DealListingURL);
    ...
}

Note that both of these solutions are prone to Activity/Fragment leakage if you are not careful, as the parent class of the Runnable/anonymous subclass is retained as an implicit reference. Be sure to cancel any outstanding AsyncTasks if the user backs out of your activity in onDestroy().

You might be able to mitigate any potential leakage issues via a static nested class, or maybe pass a Handler instance to the AsyncTask for it to send a message on when onPostExecute() has done its job. See What's the correct way to implement AsyncTask? static or non static nested class? for a discussion on this.

but how can i make progressdialog visible – Niraj Kumar Mar 18 '16 at 04:55 — Niraj Kumar, Mar 18 '16 at 04:55

How to update UI from separate AsynkTask class

2 Answers2