Download the acrobat reader .apk file for android to display pdf file
Put your pdf files on an sd card
Use the snippet of code below
File file= new File("/sdcard/test.pdf");
Uri path=Uri.fromFile(file);
Intent i =new Intent(Intent.ACTION_VIEW);
i.setDataAndType(path,"application/pdf");
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);