Android display documents(.pdf, .doc) without external app?

JAVA CODE

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    button = (Button) findViewById( R.id.mybutt );

    String pdf = "http://www.pc-hardware.hu/PDF/konfig.pdf";
    String doc="<iframe src='http://docs.google.com/gview?embedded=true&url=http://www.pc-hardware.hu/PDF/konfig.pdf' width='100%' height='100%' style='border: none;'></iframe>";
    webView = (WebView) findViewById(R.id.webView1);
    webView.getSettings().setJavaScriptEnabled(true);
    webView.getSettings().setPluginsEnabled(true);
    webView.getSettings().setAllowFileAccess(true);
    webView.loadData( doc , "text/html", "UTF-8");
}

XML

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:orientation="vertical" >

<WebView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/webView1"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

<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:gravity="bottom"
    android:orientation="vertical" >

<Button 
   android:id="@+id/mybutt"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:textSize="25sp"
   android:text="Scroll!!"
   android:layout_gravity="right"/>
</LinearLayout>