Android Recycler-Ansicht auf Bildlauf

Question

Ich möchte mehr Inhalte von meinem Adapter beim Scrollen der Recycler-Ansicht laden.Ich habe es implementiert, aber es funktioniert nicht. Meine Recycler-Ansicht funktioniert einwandfrei, aber ich kann beim Scrollen keinen Rest des Inhalts aus meiner Liste laden. Derzeit gibt es keinen Fehler in meinem Code. aber ich konnte beim Scrollen keine weiteren Objekte laden. bitte hilfe. Dies ist meine Haupttätigkeit.

public class Contact_school extends AppCompatActivity implements SearchView.OnQueryTextListener { 
private List<Contact> Listcontact = new ArrayList<>(); 
Contacts_Adapter cadapter; 
private RecyclerView rv; 
public String GET_CONTACTS = "http://xyzx.com/Publicpages_mob/brief_school_details"; 
    public Contact contact; 
public String school_id; 
String tag_json_obj = "json_obj_req"; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_contact_school); 
    rv = (RecyclerView) findViewById(R.id.recycler_view); 
    preparelist(); 
    cadapter = new Contacts_Adapter(Listcontact, rv); 
    final LinearLayoutManager layoutManager = new  LinearLayoutManager(Contact_school.this); 
    rv.setLayoutManager(layoutManager); 
    rv.setItemAnimator(new DefaultItemAnimator()); 
    rv.setAdapter(cadapter); 
    rv.setHasFixedSize(true); 

    cadapter.setOnLoadMoreListener(new OnLoadMoreListener() { 
     @Override 
     public void onLoadMore() { 

       Log.v(" KILILII ", "KITTTI"); 
     //add null , so the adapter will check view_type and show progress bar at bottom 
////    Listcontact.add(null); 
////    cadapter.notifyItemInserted(Listcontact.size() - 1); 

    // remove progress item 
////    Listcontact.remove(Listcontact.size() - 1); 
////    cadapter.notifyItemRemoved(Listcontact.size()); 
//    //add items one by one 
      int start = Listcontact.size(); 
      int end = start + 20; 
      for (int i = start + 1; i <= end; i++) { 
       Listcontact.add(contact); 
       cadapter.notifyItemInserted(Listcontact.size()); 
      } 
      cadapter.setLoaded(); 
       //or you can add all at once but do not forget to call mAdapter.notifyDataSetChanged(); 
      } 
    }); 
} 

private void preparelist() { 
    final StringRequest strReq = new StringRequest(Request.Method.POST, GET_CONTACTS,    new Response.Listener<String>() { 
     @Override 
     public void onResponse(String response) { 
      try { 
       JSONObject jObj = new JSONObject(response); 
       Log.e("RESPONSE TEST", "" + jObj); 
       JSONArray jsonArray = jObj.getJSONArray("school_details"); 
       Log.e("RESPONSE ARRAY", "" + jsonArray); 
        Log.d("SUCESS ", response); 
       for (int i = 0; i < jsonArray.length(); i++) { 
        JSONObject jsonobject = jsonArray.getJSONObject(i); 
         contact = new Contact(); 
         contact.setAddress(jsonobject.getString("school_address")); 
         contact.setRating(jsonobject.getString("school_rating")); 
     Listcontact.add(contact); 
       } 
       cadapter.notifyDataSetChanged(); 
      } catch (JSONException e) { 
       e.printStackTrace(); 
      } 

     } 
    }, new Response.ErrorListener() { 
     @Override 
     public void onErrorResponse(VolleyError error) { 
      Log.e("Error", "Registration Error: " + error.getMessage()); 
      Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_LONG).show(); 
     } 
    }) 
    { 
     @Override 
     protected Map<String, String> getParams() { 
      // Posting params to register url 
      Map<String, String> params = new HashMap<String, String>(); 
      return params; 
     } 
    }; 
    AppController.getInstance().addToRequestQueue(strReq, tag_json_obj); 
} 

das ist meine Adapterklasse

public class Contacts_Adapter extends RecyclerView.Adapter<Contacts_Adapter.MyViewHolder> { 
private List<Contact> List1; 

private final int VIEW_ITEM = 1; 
private final int VIEW_PROG = 0; 
private int visibleThreshold = 5; 
private int lastVisibleItem, totalItemCount; 
private boolean loading; 
private OnLoadMoreListener onLoadMoreListener; 
public class MyViewHolder extends RecyclerView.ViewHolder { 
     public TextView text_address,text_rating; 

    public MyViewHolder(View view) { 
     super(view); 
     text_address = (TextView)view.findViewById(R.id.textaddress); 

     text_rating = (TextView)view.findViewById(R.id.textrating); 

    } 
} 
public Contacts_Adapter(List<Contact> List1,RecyclerView recyclerView) 
{ 
    this.List1 = List1; 
    if (recyclerView.getLayoutManager() instanceof LinearLayoutManager) { 
     final LinearLayoutManager linearLayoutManager = (LinearLayoutManager) recyclerView 
       .getLayoutManager(); 
     recyclerView 
       .addOnScrollListener(new RecyclerView.OnScrollListener() { 
        @Override 
        public void onScrolled(RecyclerView recyclerView, 
              int dx, int dy) { 
         super.onScrolled(recyclerView, dx, dy); 
         totalItemCount = linearLayoutManager.getItemCount(); 
         lastVisibleItem = linearLayoutManager 
           .findLastVisibleItemPosition(); 
         if (!loading 
           && totalItemCount <= (lastVisibleItem + visibleThreshold)) { 
          // End has been reached 
          // Do something 
          if (onLoadMoreListener != null) { 
           onLoadMoreListener.onLoadMore(); 
          } 
          loading = true; 
         } 
        } 
       }); 
    } 
} 
@Override 
public int getItemViewType(int position) { 
    return List1.get(position) != null ? VIEW_ITEM : VIEW_PROG; 
} 
@Override 
public Contacts_Adapter.MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
    View itemView = LayoutInflater.from(parent.getContext()) 
      .inflate(R.layout.recycler, parent, false); 
    return new MyViewHolder(itemView); 
} 
@Override 
public void onBindViewHolder(MyViewHolder holder, final int position) { 
    Contact c = List1.get(position); 

    holder.text_rating.setText("Rating "+c.getRating()); 

    holder.text_address.setText(c.getAddress()); 

} 
public void setLoaded() { 
    loading = false; 
} 
public void setOnLoadMoreListener(OnLoadMoreListener onLoadMoreListener) { 
    this.onLoadMoreListener = onLoadMoreListener; 
} 

dies meine Modellklasse ist

public class Contact implements Serializable { 
private static final long serialVersionUID = 1L; 
    private String address,rating; 
public Contact(){ 
} 
public Contact (String address, String rating){ 
    this.address = address; 
    this.rating= rating; 

} 

public String getAddress(){ return address;} 
public String getRating(){return rating;} 
public void setAddress(String ad){ this.address= ad;} 
public void setRating(String ad){ this.rating= ad;} 
} 

und ich habe diese Schnittstelle

public interface OnLoadMoreListener { 
void onLoadMore(); 
} 

bitte helfen

Answer 1

Sie müssen die Scroll nicht verfolgen, um zu wissen, wann Sie mehr suchen müssen.

können Sie rufen die Volley Anfrage vom onBindViewHolder, zum Beispiel:

int itemsBeforeUpdate = 10; 
public void onBindViewHolder(MyViewHolder holder, final int position) { 
    Contact c = List1.get(position); 
    holder.text_rating.setText("Rating "+c.getRating()); 
    holder.text_address.setText(c.getAddress()); 
    if(List1.size() - position <10){ 
    // Do your Volley Request, add response to the list and notify the adapter that the data changed 

} 


} 

Answer 2

Statt

if (!loading && totalItemCount <= (lastVisibleItem + visibleThreshold)) { 
     // End has been reached 
     // Do something 
     if (onLoadMoreListener != null) { 
      onLoadMoreListener.onLoadMore(); 
     } 
     loading = true; 
} 

einfach führen Sie Ihre Last mehr Anfrage in diesem Block nur OnLoadMoreListener in dem folgenden Block des Aufrufs. Wie:

if (!loading&& totalItemCount <= (lastVisibleItem + visibleThreshold)) { 
    // Load your volley request or load more request her 
    loading = true; 
} 

und danach den Adapter benachrichtigen, dass die Daten geändert wurden.

Answer 3

Anstatt die Werte zur Liste in der Aktivitätsklasse hinzuzufügen, versuchen Sie es, indem Sie sie der Adapterklasse hinzufügen. Sagen Sie zum Beispiel fügen Sie eine Methode in Adapter wie unten hinzu.

public void addContact(Contact contact) { 
list.add(contact); 
notifyItemInserted(list.size()); 
} 

Und in der Aktivität statt dessen,

IHR CODE:

cadapter.setOnLoadMoreListener(new OnLoadMoreListener() { 
     @Override 
     public void onLoadMore() { 

       Log.v(" KILILII ", "KITTTI"); 
     //add null , so the adapter will check view_type and show progress bar at bottom 
////    Listcontact.add(null); 
////    cadapter.notifyItemInserted(Listcontact.size() - 1); 

    // remove progress item 
////    Listcontact.remove(Listcontact.size() - 1); 
////    cadapter.notifyItemRemoved(Listcontact.size()); 
//    //add items one by one 
      int start = Listcontact.size(); 
      int end = start + 20; 
      for (int i = start + 1; i <= end; i++) { 
       Listcontact.add(contact); 
       cadapter.notifyItemInserted(Listcontact.size()); 
      } 
      cadapter.setLoaded(); 
       //or you can add all at once but do not forget to call mAdapter.notifyDataSetChanged(); 
      } 
    }); 

VERSUCHEN SIE DIESE:

cadapter.setOnLoadMoreListener(new OnLoadMoreListener() { 
      @Override 
      public void onLoadMore() { 

        Log.v(" KILILII ", "KITTTI"); 

       int start = Listcontact.size(); 
       int end = start + 20; 
       for (int i = start + 1; i <= end; i++) { 
        cadapter.addContact(contact); 
       } 
       cadapter.setLoaded(); 
       } 
     }); 

Hope this hilfreich :)