Change Flowable to Single in Pagination

Author: amitshekhariitbhu

app/src/main/java/com/rxjava2/android/samples/ui/pagination/PaginationActivity.java

@@ -6,23 +6,19 @@
 
 import com.rxjava2.android.samples.R;
 
-import org.reactivestreams.Publisher;
-
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
-import io.reactivex.Flowable;
+import io.reactivex.Single;
 import io.reactivex.android.schedulers.AndroidSchedulers;
-import io.reactivex.annotations.NonNull;
 import io.reactivex.disposables.CompositeDisposable;
 import io.reactivex.disposables.Disposable;
-import io.reactivex.functions.Consumer;
-import io.reactivex.functions.Function;
 import io.reactivex.processors.PublishProcessor;
+import io.reactivex.schedulers.Schedulers;
 
 /**
  * Created by amitshekhar on 15/03/17.
@@ -94,23 +90,21 @@ private void subscribeForData() {
 
         Disposable disposable = paginator
                 .onBackpressureDrop()
-                .concatMap(new Function<Integer, Publisher<List<String>>>() {
-                    @Override
-                    public Publisher<List<String>> apply(@NonNull Integer page) {
-                        loading = true;
-                        progressBar.setVisibility(View.VISIBLE);
-                        return dataFromNetwork(page);
-                    }
+                .doOnNext(page -> {
+                    loading = true;
+                    progressBar.setVisibility(View.VISIBLE);
                 })
+                .concatMapSingle(page -> dataFromNetwork(page)
+                        .subscribeOn(Schedulers.io())
+                        .doOnError(throwable -> {
+                            // handle error
+                        }))
                 .observeOn(AndroidSchedulers.mainThread())
-                .subscribe(new Consumer<List<String>>() {
-                    @Override
-                    public void accept(@NonNull List<String> items) {
-                        paginationAdapter.addItems(items);
-                        paginationAdapter.notifyDataSetChanged();
-                        loading = false;
-                        progressBar.setVisibility(View.INVISIBLE);
-                    }
+                .subscribe(items -> {
+                    paginationAdapter.addItems(items);
+                    paginationAdapter.notifyDataSetChanged();
+                    loading = false;
+                    progressBar.setVisibility(View.INVISIBLE);
                 });
 
         compositeDisposable.add(disposable);
@@ -122,18 +116,15 @@ public void accept(@NonNull List<String> items) {
     /**
      * Simulation of network data
      */
-    private Flowable<List<String>> dataFromNetwork(final int page) {
-        return Flowable.just(true)
+    private Single<List<String>> dataFromNetwork(final int page) {
+        return Single.just(true)
                 .delay(2, TimeUnit.SECONDS)
-                .map(new Function<Boolean, List<String>>() {
-                    @Override
-                    public List<String> apply(@NonNull Boolean value) {
-                        List<String> items = new ArrayList<>();
-                        for (int i = 1; i <= 10; i++) {
-                            items.add("Item " + (page * 10 + i));
-                        }
-                        return items;
+                .map(value -> {
+                    List<String> items = new ArrayList<>();
+                    for (int i = 1; i <= 10; i++) {
+                        items.add("Item " + (page * 10 + i));
                     }
+                    return items;
                 });
     }
 }

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

@@ -5,4 +5,4 @@
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:padding="@dimen/activity_horizontal_margin"
-    android:textSize="20sp" />
+    android:textSize="32sp" />