This is a way for showing PDF in android app that is embedding the PDF document to android webview using support from http://docs.google.com/viewer

pseudo

String doc="<iframe src='http://docs.google.com/viewer?url=+location to your PDF File+' 
          width='100%' height='100%' 
          style='border: none;'></iframe>";

a sample is is shown below

String doc="<iframe src='http://docs.google.com/viewer?url=http://www.iasted.org/conferences/formatting/presentations-tips.ppt&embedded=true' 
          width='100%' height='100%' 
          style='border: none;'></iframe>";

Code

WebView  wv = (WebView)findViewById(R.id.webView); 
wv.getSettings().setJavaScriptEnabled(true);
wv.getSettings().setPluginsEnabled(true);
wv.getSettings().setAllowFileAccess(true);
wv.loadUrl(doc);
//wv.loadData( doc, "text/html",  "UTF-8");

and in manifest provide

<uses-permission android:name="android.permission.INTERNET"/>

SEE THIS ANSWER

EDIT

If your PDF document is accessible online, use the Google Docs Viewer to open your PDF in a WebView

REFER

 wv.loadUrl("https://docs.google.com/gview?embedded=true&url=http://www.irs.gov/pub/irs-pdf/fw4.pdf");

Don't Know how Stable These are

Here is the list of the other open sources PDF readers running on the top of the Android

• Android PDF Viewer
• APDFViewer
• droidreader
• android-pdf

Please note that these and any other project derived from MuPDF is bound by the terms of GPL and may not be suitable for the commerical use.

The following is a list of SDKs suitable for commerical use:

• PDFTron
• Adobe
• Qoppa
• Radaee