firebase
Come usare FirebaseRecyclerAdapter invece di RecyclerAdapter?

Ecco l'esempio per l'utilizzo del componente FirebaseUi FirebaseRecyclerAdapter

Ciao amici prima del codice di avvio, abbiamo bisogno di dichiarare la dipendenza per il componente ui firebase di accesso, quindi ecco la dipendenza che puoi mettere nel tuo gradel altrimenti puoi aggiungere dipendenza come jar.

compile 'com.firebaseui:firebase-ui-database:0.4.0'

Quindi, dopo aver interrogato il database di Firebase per i dati come segue

DatabaseReference databaseReference = database.getReference().child("users");
Query query = databaseReference.limitToFirst(50); 

Quindi, dopo aver passato la query all'interno di FirebaseRecyclerAdapter come seguendo la strada

private void setUpFirebaseAdapter(Query query) {

        mFirebaseAdapter = new FirebaseRecyclerAdapter<UserModel, FirebaseUserViewHolder>
                (UserModel.class, R.layout.row_user_list, FirebaseUserViewHolder.class, query) {
            @Override
            protected void populateViewHolder(FirebaseUserViewHolder viewHolder, UserModel model, int position) {
                customeLoaderDialog.hide();
                viewHolder.bindUser(model);
            }
        };

        my_recycler_view.setHasFixedSize(true);
        my_recycler_view.setLayoutManager(new LinearLayoutManager(this));
        my_recycler_view.setAdapter(mFirebaseAdapter);

    }

ChatUserModel.java (Model Class)

public class ChatUserModel {
private long badge;
private String chat_id;
private String isDelete;
private String latestactivity;
private double timestamp;
private String user_id;
private String profilePic;
private String displayName;
private boolean isGroup;
String groupId;
private String creatorId;

public String getGroupId() {
    return groupId;
}

public void setGroupId(String groupId) {
    this.groupId = groupId;
}

public String getCreatorId() {
    return creatorId;
}

public void setCreatorId(String creatorId) {
    this.creatorId = creatorId;
}

public boolean isGroup() {
    return isGroup;
}

public void setGroup(boolean group) {
    isGroup = group;
}


public ChatUserModel() {

}

public long getBadge() {
    return badge;
}

public void setBadge(long badge) {
    this.badge = badge;
}

public String getChat_id() {
    return chat_id;
}

public void setChat_id(String chat_id) {
    this.chat_id = chat_id;
}

public String getIsDelete() {
    return isDelete;
}

public void setIsDelete(String isDelete) {
    this.isDelete = isDelete;
}

public String getLatestactivity() {
    return latestactivity;
}

public void setLatestactivity(String latestactivity) {
    this.latestactivity = latestactivity;
}

public double getTimestamp() {
    return timestamp;
}

public void setTimestamp(double timestamp) {
    this.timestamp = timestamp;
}

public String getUser_id() {
    return user_id;
}

public void setUser_id(String user_id) {
    this.user_id = user_id;
}

public String getProfilePic() {
    return profilePic;
}

public void setProfilePic(String profilePic) {
    this.profilePic = profilePic;
}

public String getDisplayName() {
    return displayName;
}

public void setDisplayName(String displayName) {
    this.displayName = displayName;
}}

FirebaseChatUserViewHolder.java (Recycler ViewHolder)

public class FirebaseChatUserViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

    private static final int MAX_WIDTH = 200;
    private static final int MAX_HEIGHT = 200;
    View mView;
    Context mContext;
    ChatUserModel userModel;

    public FirebaseChatUserViewHolder(View itemView) {
        super(itemView);
        mView = itemView;
        mContext = itemView.getContext();
        itemView.setOnClickListener(this);
    }

    public void bindUser(ChatUserModel userModel) {
        this.userModel = userModel;
        ImageView imgUser = (ImageView) mView.findViewById(R.id.imgUser);
        TextView tvName = (TextView) mView.findViewById(R.id.tvName);
        TextView tvStatus = (TextView) mView.findViewById(R.id.tvStatus);
        BadgeView badgeChat = (BadgeView) mView.findViewById(R.id.badgeChat);
        if (userModel.isGroup()) {
           // imgUser.setImageDrawable(mContext.getResources().getDrawable(R.drawable.create_group));
        } else {
            Picasso.with(mContext)
                    .load(userModel.getProfilePic())
                    .resize(MAX_WIDTH, MAX_HEIGHT)
                    .centerCrop()
                    .into(imgUser);
        }

        tvName.setText(userModel.getDisplayName());
        tvStatus.setText(userModel.getLatestactivity());
        if (userModel.getBadge() > 0) {
            badgeChat.setVisibility(View.VISIBLE);
            badgeChat.setText("" + userModel.getBadge());
        } else {
            badgeChat.setVisibility(View.GONE);
        }

    }

    @Override
    public void onClick(View view) {
        if (!userModel.isGroup()) {
            Intent intent = new Intent(mContext, ChatConverstion.class);
            intent.putExtra("chat_id", "" + userModel.getChat_id());
            intent.putExtra("reciverUserName", "" + userModel.getDisplayName());
            intent.putExtra("reciverProfilePic", "" + userModel.getProfilePic());
            intent.putExtra("reciverUid", "" + userModel.getUser_id());
            mContext.startActivity(intent);
        }
    }
}

row_user_list.xml (layout per riga nella vista recycler)

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:color/white"
    android:orientation="horizontal"
   >

    <LinearLayout
        android:gravity="center_vertical"
        android:layout_width="match_parent"
        android:id="@+id/llMainChat"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:paddingTop="@dimen/margin_small"
        android:paddingLeft="@dimen/margin_small"
        android:paddingBottom="@dimen/margin_small"
        android:paddingRight="@dimen/margin_small"
        >

        <com.tristate.firebasechat.custome_view.CircleImageView
            android:id="@+id/imgUser"
            android:layout_width="@dimen/tab_top_height"
            android:layout_height="@dimen/tab_top_height"

            app:civ_border_color="@color/dark_white"
            app:civ_border_width="2dp" />

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:layout_marginLeft="@dimen/margin_medium"
         >

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical"
                android:layout_toLeftOf="@+id/badgeChat"
                android:layout_toStartOf="@+id/badgeChat"
                android:id="@+id/linearLayout">

                <TextView
                    android:id="@+id/tvName"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:ellipsize="marquee"
                    android:singleLine="true"
                    android:text="Dhaval Solanki"
                    android:textSize="@dimen/textsize_midle" />

                <TextView
                    android:id="@+id/tvStatus"
                    android:ems="3"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:gravity="center_vertical"
                    android:lines="1"
                    android:text="Online"
                    android:textColor="@color/greenStatusBar"
                    android:textSize="@dimen/textsize_small" />
            </LinearLayout>
            <com.tristate.firebasechat.custome_view.BadgeView
                android:id="@+id/badgeChat"
                android:layout_width="@dimen/margin_very_big"
                android:layout_height="@dimen/margin_very_big"
                android:layout_alignParentRight="true"
                android:layout_centerVertical="true"
                android:background="@drawable/badge_bg"
                android:gravity="center"
                android:padding="@dimen/corner_radius"
                android:text="999"
                android:textColor="@color/white"
                android:textSize="@dimen/textsize_verysmall"
                android:visibility="gone" />


        </RelativeLayout>


    </LinearLayout>
    <View
        android:layout_alignBottom="@id/llMainChat"
        android:layout_marginTop="@dimen/margin_small"
        android:layout_marginLeft="@dimen/margin_small"
        android:layout_marginRight="@dimen/margin_small"
        android:layout_width="match_parent"
        android:background="@color/avatar_back_color"
        android:layout_height="1dp"
        ></View>
</RelativeLayout>