public class OpenPdf extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button button = (Button) findViewById(R.id.OpenPdfButton);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                File file = new File("/sdcard/example.pdf");
                if (file.exists()) {
                    Uri path = Uri.fromFile(file);
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setDataAndType(path, "application/pdf");
                    intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    try {
                        startActivity(intent);
                    } catch (ActivityNotFoundException e) {
                        Toast.makeText(OpenPdf.this,
                                "No Application Available to View PDF",
                                Toast.LENGTH_SHORT).show();
                    }
                }
            }
        });
    }
}

public class OpenPdf extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button button = (Button) findViewById(R.id.OpenPdfButton);
        button.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                LoadImagefromassets();
            }
        });
    }
    Bitmap LoadImagefromassets() {
        AssetManager am = getAssets();
        Bitmap mybitmap = null;
        BufferedInputStream buf;
        try {
            InputStream in = am.open("example.pdf");
            buf = new BufferedInputStream(in);
            mybitmap = BitmapFactory.decodeStream(buf);
            if (in != null) {
                in.close();
            }
            if (buf != null) {
                buf.close();
            }
        } catch (Exception e) {
            Log.e("Error reading file", e.toString());
        }
        return mybitmap;
    }
}

public class PDFActivity extends Activity {
    private final String PDF_DATEI = "meinpdf.pdf";
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.main);
        
        try {
            Uri uri = dateiBereitstellen();
            Intent intent = new Intent(Intent.ACTION_VIEW);
            intent.setDataAndType(uri, "application/pdf");
            intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(intent);

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
    private Uri dateiBereitstellen () throws IOException {
        File sdCard = Environment.getExternalStorageDirectory();
        File datei = new File(sdCard.getAbsolutePath() + File.separator + PDF_DATEI);
        if (!datei.exists()){
            InputStream stream = this.getAssets().open(PDF_DATEI);
            String name = datei.getAbsolutePath();
            FileOutputStream outputStream = new FileOutputStream(name);
            
            byte [] puffer = new byte [50000];
            int anzahl;
            while ((anzahl = stream.read(puffer))> 0){
                outputStream.write(puffer, 0, anzahl);
            }
            outputStream.flush();
            stream.close();
            outputStream.close();
        }
        Uri uri = Uri.parse("file://" + datei.getAbsolutePath());
        return uri;
    }
}