Add sample for RecyclerView

ParseUI-Widget-Sample/build.gradle

@@ -21,6 +21,7 @@ android {
 
 dependencies {
     compile 'com.android.support:appcompat-v7:23.1.1'
+    compile 'com.android.support:recyclerview-v7:23.1.0'
     compile project(':ParseUI-Widget')
 
     testCompile 'junit:junit:4.12'

ParseUI-Widget-Sample/src/main/AndroidManifest.xml

@@ -28,6 +28,10 @@
             </intent-filter>
         </activity>
 
+        <activity
+            android:name=".RecyclerActivity"
+            android:label="@string/recycler_name"/>
+
         <activity
             android:name=".ListActivity"
             android:label="@string/list_name"/>

ParseUI-Widget-Sample/src/main/java/com/parse/ui/widget/sample/MainActivity.java

@@ -12,6 +12,7 @@ protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_main);
 
+    findViewById(R.id.sample_recycler).setOnClickListener(this);
     findViewById(R.id.sample_list).setOnClickListener(this);
   }
 
@@ -21,6 +22,11 @@ protected void onCreate(Bundle savedInstanceState) {
   public void onClick(View v) {
     int id = v.getId();
     switch (id) {
+      case R.id.sample_recycler: {
+        Intent intent = new Intent(this, RecyclerActivity.class);
+        startActivity(intent);
+        break;
+      }
       case R.id.sample_list: {
         Intent intent = new Intent(this, ListActivity.class);
         startActivity(intent);

ParseUI-Widget-Sample/src/main/java/com/parse/ui/widget/sample/RecyclerActivity.java

@@ -0,0 +1,244 @@
+package com.parse.ui.widget.sample;
+
+import android.os.Bundle;
+import android.support.v4.widget.SwipeRefreshLayout;
+import android.support.v7.app.AppCompatActivity;
+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 android.widget.ProgressBar;
+import android.widget.TextView;
+
+import com.parse.ParseObject;
+import com.parse.ParseQuery;
+import com.parse.widget.util.ParseQueryPager;
+
+import java.util.List;
+
+import bolts.CancellationTokenSource;
+import bolts.Continuation;
+import bolts.Task;
+
+public class RecyclerActivity extends AppCompatActivity {
+
+  private SwipeRefreshLayout refreshLayout;
+
+  private MyAdapter<ParseObject> adapter;
+
+  @Override
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+    setContentView(R.layout.activity_recycler);
+
+    RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler);
+
+    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this);
+    recyclerView.setLayoutManager(layoutManager);
+
+    adapter = new MyAdapter<>(createPager());
+    recyclerView.setAdapter(adapter);
+
+    refreshLayout = (SwipeRefreshLayout) findViewById(R.id.refresh);
+    refreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
+      @Override
+      public void onRefresh() {
+        final ParseQueryPager<ParseObject> pager = createPager();
+        pager.loadNextPage().continueWith(new Continuation<List<ParseObject>, Void>() {
+          @Override
+          public Void then(Task<List<ParseObject>> task) throws Exception {
+            refreshLayout.setRefreshing(false);
+
+            if (task.isCancelled()) {
+              return null;
+            }
+
+            if (task.isFaulted()) {
+              return null;
+            }
+
+            adapter.swap(pager);
+            adapter.notifyDataSetChanged();
+            return null;
+          }
+        }, Task.UI_THREAD_EXECUTOR);
+      }
+    });
+  }
+
+  private ParseQueryPager<ParseObject> createPager() {
+    ParseQuery<ParseObject> query = ParseQuery.getQuery("TestObject");
+    query.orderByAscending("name");
+    return new ParseQueryPager<>(query, 25);
+  }
+
+  public static class MyAdapter<T extends ParseObject> extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
+
+    private static final int TYPE_ITEM = 0;
+    private static final int TYPE_NEXT = 1;
+
+    private static class ItemViewHolder extends RecyclerView.ViewHolder {
+      TextView textView;
+
+      public ItemViewHolder(View itemView) {
+        super(itemView);
+        textView = (TextView) itemView;
+      }
+    }
+
+    private static class NextViewHolder extends RecyclerView.ViewHolder {
+      TextView textView;
+      ProgressBar progressBar;
+
+      public NextViewHolder(View itemView) {
+        super(itemView);
+        textView = (TextView) itemView.findViewById(android.R.id.text1);
+        progressBar = (ProgressBar) itemView.findViewById(android.R.id.progress);
+      }
+
+      public void setLoading(boolean loading) {
+        if (loading) {
+          textView.setVisibility(View.INVISIBLE);
+          progressBar.setVisibility(View.VISIBLE);
+          progressBar.setIndeterminate(true);
+        } else {
+          textView.setVisibility(View.VISIBLE);
+          progressBar.setVisibility(View.INVISIBLE);
+          progressBar.setIndeterminate(false);
+        }
+      }
+    }
+
+    private final Object lock = new Object();
+    private ParseQueryPager<T> pager;
+    private CancellationTokenSource cts;
+
+    public MyAdapter(ParseQueryPager<T> pager) {
+      swap(pager);
+    }
+
+    public ParseQueryPager<T> getPager() {
+      synchronized (lock) {
+        return pager;
+      }
+    }
+
+    public void swap(ParseQueryPager<T> pager) {
+      synchronized (lock) {
+        if (cts != null) {
+          cts.cancel();
+        }
+        this.pager = pager;
+        this.cts = new CancellationTokenSource();
+      }
+    }
+
+    private void loadNextPage() {
+      final ParseQueryPager<T> pager;
+      final CancellationTokenSource cts;
+
+      synchronized (lock) {
+        pager = this.pager;
+        cts = this.cts;
+      }
+
+      final int oldSize = pager.getObjects().size();
+
+      // Uses Tasks, so it does not support CACHE_THEN_NETWORK. See ListActivity for a sample
+      // with callbacks.
+      pager.loadNextPage(cts.getToken()).continueWith(new Continuation<List<T>, Task<Void>>() {
+        @Override
+        public Task<Void> then(Task<List<T>> task) throws Exception {
+          if (task.isCancelled()) {
+            return null;
+          }
+
+          if (task.isFaulted()) {
+            notifyDataSetChanged();
+            return null;
+          }
+
+          // Remove "Load more..."
+          notifyItemRemoved(oldSize);
+
+          // Insert results
+          List<T> results = task.getResult();
+          if (results.size() > 0) {
+            notifyItemRangeInserted(oldSize, results.size());
+          }
+
+          if (pager.hasNextPage()) {
+            // Add "Load more..."
+            notifyItemInserted(pager.getObjects().size());
+          }
+          return null;
+        }
+      });
+      notifyItemChanged(oldSize);
+    }
+
+    @Override
+    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
+      LayoutInflater inflater = LayoutInflater.from(parent.getContext());
+      switch (viewType) {
+        case TYPE_ITEM: {
+          View v = inflater.inflate(android.R.layout.simple_list_item_1, parent, false);
+          return new ItemViewHolder(v);
+        }
+        case TYPE_NEXT: {
+          View v = inflater.inflate(R.layout.load_more_list_item, parent, false);
+          v.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+              if (!getPager().isLoadingNextPage()) {
+                loadNextPage();
+              }
+            }
+          });
+          NextViewHolder vh = new NextViewHolder(v);
+          vh.textView.setText(R.string.load_more);
+          return vh;
+        }
+        default:
+          throw new IllegalStateException("Invalid view type: " + viewType);
+      }
+    }
+
+    @Override
+    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
+      switch (getItemViewType(position)) {
+        case TYPE_ITEM: {
+          ParseObject item = getPager().getObjects().get(position);
+
+          ItemViewHolder vh = (ItemViewHolder) holder;
+          vh.textView.setText(item.getString("name"));
+        }
+        break;
+        case TYPE_NEXT: {
+          NextViewHolder vh = (NextViewHolder) holder;
+          vh.setLoading(getPager().isLoadingNextPage());
+        }
+        break;
+      }
+    }
+
+    @Override
+    public int getItemCount() {
+      ParseQueryPager<T> pager = getPager();
+      return pager.getObjects().size() + (pager.hasNextPage() ? 1 : 0);
+    }
+
+    @Override
+    public int getItemViewType(int position) {
+      return position < getPager().getObjects().size() ? TYPE_ITEM : TYPE_NEXT;
+    }
+
+    @Override
+    public void registerAdapterDataObserver(RecyclerView.AdapterDataObserver observer) {
+      super.registerAdapterDataObserver(observer);
+      // We use this method as a notification that the RecyclerView is bound to the adapter.
+      loadNextPage();
+    }
+  }
+}

ParseUI-Widget-Sample/src/main/res/layout/activity_main.xml

@@ -11,6 +11,12 @@
     android:orientation="vertical"
     tools:context="com.parse.ui.widget.sample.MainActivity">
 
+    <Button
+        android:id="@+id/sample_recycler"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="@string/recycler_name"/>
+
     <Button
         android:id="@+id/sample_list"
         android:layout_width="match_parent"

ParseUI-Widget-Sample/src/main/res/layout/activity_recycler.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+              android:orientation="vertical"
+              android:layout_width="match_parent"
+              android:layout_height="match_parent">
+
+    <android.support.v4.widget.SwipeRefreshLayout
+        android:id="@+id/refresh"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+
+        <android.support.v7.widget.RecyclerView
+            android:id="@+id/recycler"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"/>
+
+    </android.support.v4.widget.SwipeRefreshLayout>
+
+</FrameLayout>

ParseUI-Widget-Sample/src/main/res/values/strings.xml

@@ -1,5 +1,6 @@
 <resources>
     <string name="app_name">ParseUI-Widget Sample</string>
+    <string name="recycler_name">RecyclerView Sample</string>
     <string name="list_name">ListView Sample</string>
 
     <string name="load_more">Load more…</string>