PDF viewer (Minimum SDK version 21)

import android.app.Activity;
import android.app.Fragment;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.pdf.PdfRenderer;
import android.os.Bundle;
import android.os.ParcelFileDescriptor;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

import java.io.IOException;


public class PdfRendererBasicFragment extends Fragment implements View.OnClickListener 
{
  
    private static final String STATE_CURRENT_PAGE_INDEX = "current_page_index";

    private ParcelFileDescriptor mFileDescriptor;
    private PdfRenderer mPdfRenderer;
    private PdfRenderer.Page mCurrentPage;
    private ImageView mImageView;
    private Button mButtonPrevious;
    private Button mButtonNext;

    public PdfRendererBasicFragment()
    {

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState)
    {
      return inflater.inflate(R.layout.fragment_pdf_renderer_basic, container, false);
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) 
    {
        super.onViewCreated(view, savedInstanceState);
        mImageView = (ImageView) view.findViewById(R.id.image);
        mButtonPrevious = (Button) view.findViewById(R.id.previous);
        mButtonNext = (Button) view.findViewById(R.id.next);
        mButtonPrevious.setOnClickListener(this);
        mButtonNext.setOnClickListener(this);
        int index = 0;
        
        if (null != savedInstanceState) 
        {
            index = savedInstanceState.getInt(STATE_CURRENT_PAGE_INDEX, 0);
        }

        showPage(index);
    }

    @Override

    public void onAttach(Activity activity) 
        {
        super.onAttach(activity);
        try 
        {
            openRenderer(activity);
        } 
        catch (IOException e) 
        {
            e.printStackTrace();
            activity.finish();
        }
    }

    @Override

    public void onDetach() 
    {
        try 
        {
            closeRenderer();
        } 
        catch (IOException e) 
        {
            e.printStackTrace();
        }
        super.onDetach();
    }

    @Override
    public void onSaveInstanceState(Bundle outState) 
     {
        super.onSaveInstanceState(outState);
        if (null != mCurrentPage)
        {
            outState.putInt(STATE_CURRENT_PAGE_INDEX, mCurrentPage.getIndex());
        }
    }

   private void openRenderer(Context context) throws IOException 
    {
     mFileDescriptor = context.getAssets().openFd("sample.pdf").getParcelFileDescriptor();
      mPdfRenderer = new PdfRenderer(mFileDescriptor );

    }

    
    private void closeRenderer() throws IOException
    {
        if (null != mCurrentPage) 
        {
            mCurrentPage.close();
        }
        mPdfRenderer.close();
        mFileDescriptor.close();
    }

   
    private void showPage(int index) 
    {
        if (mPdfRenderer.getPageCount() <= index) 
        {
            return;
        }
      
        if (null != mCurrentPage) 
        {
            mCurrentPage.close();
        }
        
        mCurrentPage = mPdfRenderer.openPage(index);
     
        Bitmap bitmap = Bitmap.createBitmap(mCurrentPage.getWidth(), mCurrentPage.getHeight(),Bitmap.Config.ARGB_8888);
       
        mCurrentPage.render(bitmap, null, null, PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY);
       
        mImageView.setImageBitmap(bitmap);
        updateUi();
    }

   
    private void updateUi() 
    {
        int index = mCurrentPage.getIndex();
        int pageCount = mPdfRenderer.getPageCount();
        mButtonPrevious.setEnabled(0 != index);
        mButtonNext.setEnabled(index + 1 < pageCount);
        getActivity().setTitle(getString(R.string.app_name_with_index, index + 1, pageCount));
    }

    public int getPageCount() 
    {
        return mPdfRenderer.getPageCount();
    }

    @Override
    public void onClick(View view) 
    {
        switch (view.getId()) 
        {
            case R.id.previous:
            {
               showPage(mCurrentPage.getIndex() - 1);
               break;
            }
            case R.id.next: 
            {
               showPage(mCurrentPage.getIndex() + 1);
               break;
            }
        }
    }
}

============================
// CALL From Activity
=============================

public static final String FRAGMENT_PDF_RENDERER_BASIC= "pdf_renderer_basic";
@Override
protected void onCreate(Bundle savedInstanceState)
 {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main_real);
    if (savedInstanceState == null)
    { 
         getFragmentManager().beginTransaction().add(R.id.container, new PdfRendererBasicFragment(),FRAGMENT_PDF_RENDERER_BASIC).commit();
    }
}

=============
XML FILES
==============
1) Fragment
<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="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity$PlaceholderFragment">

    <ImageView
        android:id="@+id/image"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:background="@android:color/white"
        android:scaleType="fitCenter" />

    <LinearLayout
        style="?android:attr/buttonBarStyle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:measureWithLargestChild="true"
        android:orientation="horizontal">

        <Button
            android:id="@+id/previous"
            style="?android:attr/buttonBarButtonStyle"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/previous" />

        <Button
            android:id="@+id/next"
            style="?android:attr/buttonBarButtonStyle"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/next" />
    </LinearLayout>

</LinearLayout>

2. Activity

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    tools:ignore="MergeRootFrame" />