Firestore paging adapter

app/src/main/AndroidManifest.xml

@@ -43,6 +43,11 @@
             android:name=".database.firestore.FirestoreChatActivity"
             android:label="@string/title_firestore_activity" />
 
+        <!-- Firestore paging demo -->
+        <activity
+            android:name=".database.firestore.FirestorePagingActivity"
+            android:label="@string/title_firestore_paging_activity" />
+
         <!-- Realtime database demo -->
         <activity
             android:name=".database.realtime.RealtimeDbChatActivity"

app/src/main/java/com/firebase/uidemo/ChooserActivity.java

@@ -28,6 +28,7 @@
 
 import com.firebase.uidemo.auth.AuthUiActivity;
 import com.firebase.uidemo.database.firestore.FirestoreChatActivity;
+import com.firebase.uidemo.database.firestore.FirestorePagingActivity;
 import com.firebase.uidemo.database.realtime.RealtimeDbChatActivity;
 import com.firebase.uidemo.storage.ImageActivity;
 
@@ -53,20 +54,23 @@ private static class ActivityChooserAdapter extends RecyclerView.Adapter<Activit
         private static final Class[] CLASSES = new Class[]{
                 AuthUiActivity.class,
                 FirestoreChatActivity.class,
+                FirestorePagingActivity.class,
                 RealtimeDbChatActivity.class,
                 ImageActivity.class,
         };
 
         private static final int[] DESCRIPTION_NAMES = new int[]{
                 R.string.title_auth_activity,
                 R.string.title_firestore_activity,
+                R.string.title_firestore_paging_activity,
                 R.string.title_realtime_database_activity,
                 R.string.title_storage_activity
         };
 
         private static final int[] DESCRIPTION_IDS = new int[]{
                 R.string.desc_auth,
                 R.string.desc_firestore,
+                R.string.desc_firestore_paging,
                 R.string.desc_realtime_database,
                 R.string.desc_storage
         };

app/src/main/java/com/firebase/uidemo/database/firestore/FirestorePagingActivity.java

@@ -0,0 +1,194 @@
+package com.firebase.uidemo.database.firestore;
+
+import android.arch.paging.PagedList;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.v7.app.AppCompatActivity;
+import android.support.v7.widget.LinearLayoutManager;
+import android.support.v7.widget.RecyclerView;
+import android.util.Log;
+import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ProgressBar;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import com.firebase.ui.firestore.paging.FirestorePagingAdapter;
+import com.firebase.ui.firestore.paging.FirestorePagingOptions;
+import com.firebase.ui.firestore.paging.LoadingState;
+import com.firebase.uidemo.R;
+import com.google.android.gms.tasks.OnCompleteListener;
+import com.google.android.gms.tasks.Task;
+import com.google.firebase.firestore.CollectionReference;
+import com.google.firebase.firestore.FirebaseFirestore;
+import com.google.firebase.firestore.Query;
+import com.google.firebase.firestore.WriteBatch;
+
+import java.util.Locale;
+
+import butterknife.BindView;
+import butterknife.ButterKnife;
+
+public class FirestorePagingActivity extends AppCompatActivity {
+
+    private static final String TAG = "FirestorePagingActivity";
+
+    @BindView(R.id.paging_recycler)
+    RecyclerView mRecycler;
+
+    @BindView(R.id.paging_loading)
+    ProgressBar mProgressBar;
+
+    private FirebaseFirestore mFirestore;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_firestore_paging);
+        ButterKnife.bind(this);
+
+        mFirestore = FirebaseFirestore.getInstance();
+        mProgressBar.setIndeterminate(true);
+
+        setUpAdapter();
+    }
+
+    private void setUpAdapter() {
+        Query baseQuery = mFirestore.collection("items")
+                .orderBy("value", Query.Direction.ASCENDING);
+
+        PagedList.Config config = new PagedList.Config.Builder()
+                .setEnablePlaceholders(false)
+                .setPrefetchDistance(10)
+                .setPageSize(20)
+                .build();
+
+        FirestorePagingOptions<Item> options = new FirestorePagingOptions.Builder<Item>()
+                .setLifecycleOwner(this)
+                .setQuery(baseQuery, config, Item.class)
+                .build();
+
+        FirestorePagingAdapter<Item, ItemViewHolder> adapter =
+                new FirestorePagingAdapter<Item, ItemViewHolder>(options) {
+                    @NonNull
+                    @Override
+                    public ItemViewHolder onCreateViewHolder(@NonNull ViewGroup parent,
+                                                             int viewType) {
+                        View view = LayoutInflater.from(parent.getContext())
+                                .inflate(R.layout.item_item, parent, false);
+                        return new ItemViewHolder(view);
+                    }
+
+                    @Override
+                    protected void onBindViewHolder(@NonNull ItemViewHolder holder,
+                                                    int position,
+                                                    Item model) {
+                        holder.bind(model);
+                    }
+
+                    @Override
+                    protected void onLoadingStateChanged(@NonNull LoadingState state) {
+                        switch (state) {
+                            case LOADING_INITIAL:
+                            case LOADING_MORE:
+                                mProgressBar.setVisibility(View.VISIBLE);
+                                break;
+                            case LOADED:
+                                mProgressBar.setVisibility(View.GONE);
+                                break;
+                            case ERROR:
+                                showToast("An error occurred.");
+                                break;
+                        }
+                    }
+                };
+
+        mRecycler.setLayoutManager(new LinearLayoutManager(this));
+        mRecycler.setAdapter(adapter);
+    }
+
+    @Override
+    public boolean onCreateOptionsMenu(Menu menu) {
+        getMenuInflater().inflate(R.menu.menu_firestore_paging, menu);
+        return super.onCreateOptionsMenu(menu);
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        if (item.getItemId() == R.id.item_add_data) {
+            showToast("Adding data...");
+            createItems().addOnCompleteListener(this, new OnCompleteListener<Void>() {
+                @Override
+                public void onComplete(@NonNull Task<Void> task) {
+                    if (task.isSuccessful()) {
+                        showToast("Data added.");
+                    } else {
+                        Log.w(TAG, "addData", task.getException());
+                        showToast("Error adding data.");
+                    }
+                }
+            });
+
+            return true;
+        }
+        return super.onOptionsItemSelected(item);
+    }
+
+    private Task<Void> createItems() {
+
+        WriteBatch writeBatch = mFirestore.batch();
+        CollectionReference collRef = mFirestore.collection("items");
+
+        for (int i = 0; i < 500; i++) {
+            String title = "Item " + i;
+
+            String id = String.format(Locale.getDefault(), "item_%03d", i);
+            Item item = new Item(title, i);
+
+            writeBatch.set(collRef.document(id), item);
+        }
+
+        return writeBatch.commit();
+    }
+
+    private void showToast(String message) {
+        Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
+    }
+
+    public static class Item {
+
+        public String text;
+        public int value;
+
+        public Item() {}
+
+        public Item(String text, int value) {
+            this.text = text;
+            this.value = value;
+        }
+
+    }
+
+    public static class ItemViewHolder extends RecyclerView.ViewHolder {
+
+        @BindView(R.id.item_text)
+        TextView mTextView;
+
+        @BindView(R.id.item_value)
+        TextView mValueView;
+
+        ItemViewHolder(View itemView) {
+            super(itemView);
+            ButterKnife.bind(this, itemView);
+        }
+
+        void bind(Item item) {
+            mTextView.setText(item.text);
+            mValueView.setText(String.valueOf(item.value));
+        }
+    }
+
+}

app/src/main/res/layout/activity_firestore_paging.xml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<RelativeLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context="com.firebase.uidemo.database.firestore.FirestorePagingActivity">
+
+    <ProgressBar
+        android:id="@+id/paging_loading"
+        style="?android:attr/progressBarStyleHorizontal"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="-6dp"
+        android:background="@android:color/transparent"
+        tools:ignore="NegativeMargin" />
+
+    <android.support.v7.widget.RecyclerView
+        android:id="@+id/paging_recycler"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_below="@+id/paging_loading"
+        android:paddingLeft="16dp"
+        android:paddingRight="16dp"
+        android:paddingTop="8dp"
+        android:clipToPadding="false"
+        tools:listitem="@layout/item_item" />
+
+</RelativeLayout>

app/src/main/res/layout/item_item.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:layout_marginBottom="8dp"
+    android:paddingLeft="16dp"
+    android:paddingRight="16dp"
+    android:paddingTop="8dp"
+    android:paddingBottom="8dp"
+    android:background="@drawable/ic_chat_message_background"
+    android:orientation="vertical">
+
+    <TextView
+        android:id="@+id/item_text"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:textIsSelectable="false"
+        android:textSize="16sp"
+        android:textStyle="bold"
+        tools:text="My Text" />
+
+    <TextView
+        android:id="@+id/item_value"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:textIsSelectable="false"
+        android:textSize="12sp"
+        tools:text="1234" />
+
+</LinearLayout>

app/src/main/res/menu/menu_firestore_paging.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <item
+        android:id="@+id/item_add_data"
+        android:title="@string/menu_add_data"
+        app:showAsAction="never" />
+
+</menu>

app/src/main/res/values/strings.xml

@@ -4,11 +4,13 @@
     <!-- Chooser -->
     <string name="title_auth_activity">Auth UI demo</string>
     <string name="title_firestore_activity">Cloud Firestore Demo</string>
+    <string name="title_firestore_paging_activity">Cloud Firestore Paging Demo</string>
     <string name="title_realtime_database_activity">Real-time database demo</string>
     <string name="title_storage_activity">Storage Image Demo</string>
 
     <string name="desc_auth">Demonstrates the Firebase Auth UI flow, with customization options.</string>
     <string name="desc_firestore">Demonstrates using a FirestoreRecyclerAdapter to load data from Cloud Firestore into a RecyclerView for a basic chat app.</string>
+    <string name="desc_firestore_paging">Demonstrates using a FirestorePagingAdapter to load/infinite scroll paging data from Cloud Firestore.</string>
     <string name="desc_realtime_database">Demonstrates using a FirebaseRecyclerAdapter to load data from Firebase Database into a RecyclerView for a basic chat app.</string>
     <string name="desc_storage">Demonstrates displaying an image from Cloud Storage using Glide.</string>
 
@@ -97,5 +99,7 @@
         Make sure your device is online and that Anonymous Auth is configured in your Firebase project
         (https://console.firebase.google.com/project/_/authentication/providers)
     </string>
+
+    <string name="menu_add_data">Add Data</string>
     <string name="hint_message">Say something…</string>
 </resources>

constants.gradle

@@ -10,6 +10,6 @@ project.ext {
 
     firebaseVersion = '12.0.1'
     supportLibraryVersion = '27.1.0'
-    architectureVersion = '1.1.0'
+    architectureVersion = '1.1.1'
     kotlinVersion = '1.2.30'
 }

firestore/build.gradle

@@ -22,6 +22,8 @@ dependencies {
     api "com.android.support:recyclerview-v7:$supportLibraryVersion"
     annotationProcessor "android.arch.lifecycle:compiler:$architectureVersion"
 
+    api "android.arch.paging:runtime:1.0.0-beta1"
+
     androidTestImplementation 'junit:junit:4.12'
     androidTestImplementation 'com.android.support.test:runner:1.0.1'
     androidTestImplementation 'com.android.support.test:rules:1.0.1'