Pull to refresh recyclerview android

Question

Hi I've a tabbed activity, and in the first tab I fetch data from server and show it in a recyclerview within card views. For fetching the data from server I use the volley library. I want to implement the Pull to refresh to load the data (so whenever I pull it has to do the request to the network). And I want also to disable the network request whenever I switch between tabs (because when I change tab focus in my app it starts to fetching data) I want to do the network request only 1 time (when user log in first time) and then others requests maneged only by pull to refresh.

Here's my fragment where I've recyclerview and show the data:

public class Tab1History extends Fragment {  private RecyclerView recyclerView; private CespiteAdapter adapter; UserSessionManager session;  private static final String URL_DATA = "http://mydata.php";  private List<CespiteOgg> cespiteOggList;  @Override public View onCreateView(LayoutInflater inflater, ViewGroup container,                          Bundle savedInstanceState) {      View rootView = inflater.inflate(R.layout.tab1history, container, false);      recyclerView = (RecyclerView) rootView.findViewById(R.id.my_recycler_view);     recyclerView.setHasFixedSize(true);//every item of the RecyclerView has a fix size     recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));      cespiteOggList = new ArrayList<>();      loadRecyclerViewData();              return rootView; }  private void loadRecyclerViewData() {     // Session class instance     session = new UserSessionManager(getActivity());     //get user data from session     HashMap<String, String> user = session.getUserDetails();     //get name     String name = user.get(UserSessionManager.KEY_NAME);     // get username     final String usernameUtente = user.get(UserSessionManager.KEY_USERNAME);      final ProgressDialog progressDialog = new ProgressDialog(getActivity());     progressDialog.setMessage("Carimento dati...");     progressDialog.show();      StringRequest stringRequest = new StringRequest(Request.Method.POST,             URL_DATA,             new Response.Listener<String>() {                 @Override                 public void onResponse(String s) {                     progressDialog.dismiss();                     try {                         JSONObject jsonObject = new JSONObject(s);                         JSONArray array = jsonObject.getJSONArray("dates");                          for(int i=0; i<array.length(); i++)                         {                             JSONObject o = array.getJSONObject(i);                             CespiteOgg item = new CespiteOgg(                                     o.getString("CodNumInventario"),                                     o.getString("Nome"),                                     o.getString("DtCatalogazione"),                                     o.getString("CodIdA"),                                     o.getString("username")                             );                             cespiteOggList.add(item);                         }                          adapter = new CespiteAdapter(cespiteOggList, getActivity());                         recyclerView.setAdapter(adapter);                      } catch (JSONException e) {                         e.printStackTrace();                     }                  }             },             new Response.ErrorListener() {                 @Override                 public void onErrorResponse(VolleyError error) {                     progressDialog.dismiss();                 }             })             {                 @Override                 protected Map<String, String> getParams() throws AuthFailureError {                     Map<String, String> params = new HashMap<String, String>();                     params.put("Username", usernameUtente);                     return params;                 }             };      RegisterRequest.getmInstance(getActivity()).addToRequestque(stringRequest);  } } 

And it's the adapter:

public class CespiteAdapter extends RecyclerView.Adapter<CespiteAdapter.ViewHolder> {   private List<CespiteOgg> cespiteOggList; private Context context;  public CespiteAdapter(List<CespiteOgg> cespiteOggList, Context context) {      this.cespiteOggList = cespiteOggList;     this.context = context; }  public class ViewHolder extends RecyclerView.ViewHolder {      public CardView cv;     public TextView txtNumInventario;     public TextView txtNomeCespite;     public TextView txtDtCatalogazione;     public TextView txtAula;     public TextView txtNomeUser;       ViewHolder(View itemView)     {          super (itemView);         //cv = (CardView) itemView.findViewById(R.id.cardView);         txtNumInventario = (TextView) itemView.findViewById(R.id.txtNumeroInventario);         txtNomeCespite = (TextView) itemView.findViewById(R.id.txtNomeCespite);         txtDtCatalogazione = (TextView) itemView.findViewById(R.id.txtDataCatalogazione);         txtAula = (TextView) itemView.findViewById(R.id.txtAula);         txtNomeUser= (TextView) itemView.findViewById(R.id.txtNomeUser);       } }    @Override public CespiteAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {      LayoutInflater inflater = LayoutInflater.from(parent.getContext());      View cespiteView = inflater.inflate(R.layout.cespite_card_view, parent, false);      return new ViewHolder(cespiteView); }  @Override public void onBindViewHolder(ViewHolder holder, int position) {      CespiteOgg cespiteOgg = cespiteOggList.get(position);      holder.txtNumInventario.setText(cespiteOgg.getNumInventario());     holder.txtNomeCespite.setText(cespiteOgg.getNomeCespite());     holder.txtDtCatalogazione.setText(cespiteOgg.getDtCatalogazione());     holder.txtAula.setText(cespiteOgg.getAula());     holder.txtNomeUser.setText(cespiteOgg.getNomeUser());  }  @Override public int getItemCount() {      return cespiteOggList.size(); }  } 

Answer 1

You can use android SwipeRefreshLayout widget instead of ProgressDialog.

Follow below steps to integrate SwipeRefreshLayout in your Tab1history fragment:

1. In your layout tab1history, add SwipeRefreshLayout as a root layout and place RecyclewrView inside it.

// tab1history.xml <?xml version="1.0" encoding="utf-8"?> <android.support.v4.widget.SwipeRefreshLayout     xmlns:android="http://schemas.android.com/apk/res/android"     android:id="@+id/swipe_container"     android:layout_width="match_parent"     android:layout_height="match_parent">          <android.support.v7.widget.RecyclerView             android:id="@+id/my_recycler_view"             android:layout_width="match_parent"             android:layout_height="match_parent" />  </android.support.v4.widget.SwipeRefreshLayout> 

2. In your Tab1History fragment, use SwipeRefreshLayout as below to load data from server:

// Tab1History.java import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.widget.SwipeRefreshLayout; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.RecyclerView; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup;  import com.android.volley.Request; import com.android.volley.Response; import com.android.volley.toolbox.StringRequest;  import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject;  import java.util.ArrayList;   public class Tab1History extends Fragment implements SwipeRefreshLayout.OnRefreshListener {      SwipeRefreshLayout mSwipeRefreshLayout;     private RecyclerView recyclerView;     private CespiteAdapter adapter;     UserSessionManager session;      private static final String URL_DATA = "http://mydata.php";      private List<CespiteOgg> cespiteOggList;      @Override     public View onCreateView(LayoutInflater inflater, ViewGroup container,                              Bundle savedInstanceState)     {          View rootView = inflater.inflate(R.layout.tab1history, container, false);           recyclerView = (RecyclerView) rootView.findViewById(R.id.my_recycler_view);         recyclerView.setHasFixedSize(true);//every item of the RecyclerView has a fix size         recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));          cespiteOggList = new ArrayList<>();           // SwipeRefreshLayout         mSwipeRefreshLayout = (SwipeRefreshLayout) rootView.findViewById(R.id.swipe_container);         mSwipeRefreshLayout.setOnRefreshListener(this);         mSwipeRefreshLayout.setColorSchemeResources(R.color.colorPrimary,                 android.R.color.holo_green_dark,                 android.R.color.holo_orange_dark,                 android.R.color.holo_blue_dark);          /**          * Showing Swipe Refresh animation on activity create          * As animation won't start on onCreate, post runnable is used          */         mSwipeRefreshLayout.post(new Runnable() {              @Override             public void run() {                  mSwipeRefreshLayout.setRefreshing(true);                  // Fetching data from server                 loadRecyclerViewData();             }         });          return rootView;     }      /**      * This method is called when swipe refresh is pulled down      */     @Override     public void onRefresh() {          // Fetching data from server         loadRecyclerViewData();     }      private void loadRecyclerViewData()     {         // Showing refresh animation before making http call         mSwipeRefreshLayout.setRefreshing(true);          // Session class instance         session = new UserSessionManager(getActivity());         //get user data from session         HashMap<String, String> user = session.getUserDetails();         //get name         String name = user.get(UserSessionManager.KEY_NAME);         // get username         final String usernameUtente = user.get(UserSessionManager.KEY_USERNAME);           StringRequest stringRequest = new StringRequest(Request.Method.POST,                 URL_DATA,                 new Response.Listener<String>() {                     @Override                     public void onResponse(String s) {                          try {                             JSONObject jsonObject = new JSONObject(s);                             JSONArray array = jsonObject.getJSONArray("dates");                              for(int i=0; i<array.length(); i++)                             {                                 JSONObject o = array.getJSONObject(i);                                 CespiteOgg item = new CespiteOgg(                                         o.getString("CodNumInventario"),                                         o.getString("Nome"),                                         o.getString("DtCatalogazione"),                                         o.getString("CodIdA"),                                         o.getString("username")                                 );                                 cespiteOggList.add(item);                             }                              adapter = new CespiteAdapter(cespiteOggList, getActivity());                             recyclerView.setAdapter(adapter);                          } catch (JSONException e) {                             e.printStackTrace();                         }                          // Stopping swipe refresh                         mSwipeRefreshLayout.setRefreshing(false);                      }                 },                 new Response.ErrorListener() {                     @Override                     public void onErrorResponse(VolleyError error) {                          // Stopping swipe refresh                         mSwipeRefreshLayout.setRefreshing(false);                     }                 })         {             @Override             protected Map<String, String> getParams() throws AuthFailureError {                 Map<String, String> params = new HashMap<String, String>();                 params.put("Username", usernameUtente);                 return params;             }         };          RegisterRequest.getmInstance(getActivity()).addToRequestque(stringRequest);      } } 

Hope this will work properly.

Answer 2

XML code

<androidx.swiperefreshlayout.widget.SwipeRefreshLayout         android:id="@+id/swipe_layout"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:layout_below="@id/layout_titlebar">      <androidx.recyclerview.widget.RecyclerView         android:id="@+id/recyclerview"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:layout_below="@id/layout_titlebar"         android:layout_margin="5dp"         />      </androidx.swiperefreshlayout.widget.SwipeRefreshLayout> 

Java code

public class BooksActivity extends AppCompatActivity implements SwipeRefreshLayout.OnRefreshListener {              SwipeRefreshLayout swipLayout;             RecyclerView recyclerview;          @Override             protected void onCreate(@Nullable Bundle savedInstanceState) {                 super.onCreate(savedInstanceState);                 setContentView(R.layout.activity);                 recyclerview = view.findViewById(R.id.recyclerview);                 swipLayout = view.findViewById(R.id.swipe_layout);                 swipLayout.setOnRefreshListener(this);             }//end of onCreate          @Override             public void onRefresh() {         //your refresh code here            loadRecyclerViewData()              }          private void loadRecyclerViewData(){         onSuccess(){         //don't forget to stop refreshing         swipLayout.setRefreshing(false);         }          onFaliure(){         //don't forget to stop refreshing         swipLayout.setRefreshing(false);         }     }     }