FirebasePaginator

Simple library to paginate data with Firebase database.

Sample app

---

Usage

1- Add Firebase to your project.

2- Add to your build.gradle level project.

 allprojects {
   repositories {
       .....
       maven{
           url 'https://dl.bintray.com/isds/FirebasePaginator'
       }
       ....
   }
}

3- And build.gradle app level.

  dependencies{
  ....
      compile 'com.santana.isaias:firebasepaginatorrecycleradapter:1.0'
  ....
  }

4- Create your model class, i.e:

public final class Contact
{
    private  String contactName;
    private  String phoneNumber;

    public Contact(String contactName, String phoneNumber)
    {
        this.contactName = contactName;
        this.phoneNumber = phoneNumber;
    }

    public Contact(){}

    public String getContactName() { return contactName; }

    public String getPhoneNumber() { return phoneNumber; }
    
    @Exclude
    public HashMap<String, Object> toMap()
    {
        final HashMap<String, Object> map = new HashMap<>();
        map.put("contactName",contactName);
        map.put("phoneNumber",phoneNumber);

        return map;
    }
}

5- Create your ViewHolder.

  
public final class ContactListViewHolder extends RecyclerView.ViewHolder
{
    private TextView label;
    private TextView contactName;
    private TextView contactPhone;

    public ContactListViewHolder(View view)
    {
        super(view);
        label        = (TextView) view.findViewById(R.id.labelFirstLetterRow);
        contactName  = (TextView) view.findViewById(R.id.tvContactNameRow);
        contactPhone = (TextView) view.findViewById(R.id.tvContactPhoneRow);
    }

    public TextView getLabel() { return label; }

    public TextView getContactName() { return contactName; }

    public TextView getContactPhone() { return contactPhone; }
}

6- Create your Adpater:

• make your extends FirebasePaginatorRecyclerAdapter<YourModel,YourViewHolder>
• And override populateViewHolder(ViewHolderClass yourViewHolder, ModelClass yourModelClass, int positionItemAdapter)

   
public final class ContactsListAdapter extends FirebasePaginatorRecyclerAdapter<Contact,ContactListViewHolder>
{
  private final Context context;

  
  
 /**
   * @param modelClass       Your model class.
   * @param layout           The layout resource id to inflate the viewHolder.
   * @param viewHolderClass  The ViewHolder class.
   * @param query            The reference to your data on database. i.e                       
                             FirebaseDatabase.getInstance().getReference(YOUR_NODE). Just add the reference.
  * @param totalDataPerPage the number of data recovered from database. Default limit is 21.
   */
  public ContactsListAdapter(Class<Contact> modelClass,
                             @LayoutRes int layout,
                             Class<ContactListViewHolder> viewHolderClass,
                             Query query,
                             int totalDataPerPage,
                             Context context /* maybe you need*/)
  {
      super(modelClass, layout, viewHolderClass, query, totalDataPerPage);
      this.context = context;
  }    

  @Override
  protected void populateViewHolder(ContactListViewHolder viewHolder,
                                    Contact model,
                                    int position)
  {
      final int color = getRandomMaterialColor("400");

      viewHolder.getLabel().setText(Character.toString(model.getContactName().toUpperCase().charAt(0)));
      DrawableCompat.setTint(DrawableCompat.wrap(viewHolder.getLabel().getBackground()),color);
      viewHolder.getContactName().setText(model.getContactName());
      viewHolder.getContactPhone().setText(model.getPhoneNumber());
  }
  
  ...
}      

7 - Attach in the recyclerview.

  @Override
   protected void onCreate(Bundle savedInstanceState)
   {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_contact_list);

       findViewById(R.id.my_progress_bar).setVisibility(View.VISIBLE);
       
       final DatabaseReference reference = FirebaseDatabase.getInstance()
                                                           .getReference()
                                                           .child(YOUR_NODE_CONTACTS); //i.e contactList.

       final ContactsListAdapter contactsListAdapter = new ContactsListAdapter(Contact.class,
               R.layout.row_contact,
               ContactListViewHolder.class,
               reference,
               10/*totalDataPerPage*/,
               context);

       final RecyclerView recyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
       final LinearLayoutManager llm =
                                 new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);



       recyclerView.setLayoutManager(llm);
       recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL));
       recyclerView.setHasFixedSize(false);
       recyclerView.setAdapter(contactsListAdapter);
       recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
           @Override
           public void onScrolled(RecyclerView recyclerView, int dx, int dy)
           {
               super.onScrolled(recyclerView, dx, dy);

               final int totalItemCount =  llm.getItemCount();
               final int lastVisibleItem = llm.findLastCompletelyVisibleItemPosition();


               if(!contactsListAdapter.isLoading() && totalItemCount <= (lastVisibleItem + 2))
               {
                   contactsListAdapter.loadMore();
               }
           }
       });
   }