Why Fragment is not displayed in ViewPager

There are activations in it through the ViewPager articles are displayed. Inside the viewpager fragments. The problem is that the fragments are not displayed, I can not understand why ((

ArticleActivity.java

public class ArticleActivity extends FragmentActivity { private int articleOrderNumber; private PagerAdapter pagerAdapter; private ViewPager viewPager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_article); pagerAdapter = new ArticleActivityPagerAdapter(getSupportFragmentManager(), ((MyApplication) getApplication()).getArticles().size()); viewPager = (ViewPager) findViewById(R.id.viewPager); viewPager.setAdapter(pagerAdapter); viewPager.setCurrentItem(articleOrderNumber - 1); } } 

activity_article.xml

 <?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" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" tools:context=".ArticleActivity" android:orientation="vertical"> <ImageView android:id="@+id/backButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_alignParentLeft="true" android:layout_gravity="left" android:src = "@drawable/back" android:gravity="left"/> <ImageView android:id="@+id/menuButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:clickable="true" android:src="@drawable/pocke_ball" android:layout_centerHorizontal="true" android:layout_alignParentBottom="true" /> <ImageView android:id="@+id/nextButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="right" android:layout_alignParentBottom="true" android:layout_alignParentRight="true" android:clickable="true" android:src = "@drawable/forward" android:text="next" /> <android.support.v4.view.ViewPager android:layout_width="match_parent" android:layout_height="match_parent" android:clickable="true" android:layout_above="@id/menuButton" android:id="@+id/viewPager"/> 

ArticleActivityPagerAdapter.java

  public class ArticleActivityPagerAdapter extends FragmentStatePagerAdapter { private int countOfArticles; public ArticleActivityPagerAdapter(FragmentManager fm, int countOfArticles) { super(fm); this.countOfArticles = countOfArticles; } @Override public int getCount() { return countOfArticles; } @Override public Fragment getItem(int position) { return ArticleFragment.newInstance(position); } @Override public boolean isViewFromObject(View view, Object object) { return view == object; } } 

ArticleFragment.java

 public class ArticleFragment extends Fragment { int articleOrderNumber; public static ArticleFragment newInstance(int page) { ArticleFragment fragment = new ArticleFragment(); Bundle args = new Bundle(); args.putInt(Article.ORDER_NUMBER, page + 1); fragment.setArguments(args); return fragment; } @Override public void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); articleOrderNumber = getArguments().getInt(Article.ORDER_NUMBER); } @Nullable @Override public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { Activity activity = getActivity(); View rootView = inflater.inflate( R.layout.article_fragment, container, false); ArticleRepository articles = ((MyApplication) activity.getApplication()).getArticles(); Article article = articles.getByOrderNumber(articleOrderNumber); RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(activity); RecyclerView recView = (RecyclerView)rootView.findViewById(R.id.articleRecView); recView.setLayoutManager(layoutManager); recView.setAdapter(new ArticleRecViewAdapter(article, activity)); return rootView; } } 

article_fragment.xml

 <?xml version="1.0" encoding="utf-8"?> <FrameLayout 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=".ArticleFragment"> <android.support.v7.widget.RecyclerView android:layout_width="match_parent" android:layout_height="match_parent" android:requiresFadingEdge="vertical" android:id="@+id/articleRecView" /> </FrameLayout>