android: how do i open another app from my app?

How to see if Intent is available:

1. Try calling Intent and deal with ActivityNotFoundException if it isn’t available

   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();
   }
   

   or

2. Query the Package Manager to see if it is ahead of time:

   PackageManager packageManager = getPackageManager();
   Intent intent = new Intent(Intent.ACTION_VIEW);
   intent.setType("application/pdf");
   
   List list = packageManager.queryIntentActivities(intent,
       PackageManager.MATCH_DEFAULT_ONLY);
   
   if (list.size() > 0) {
       intent.setDataAndType(path, "application/pdf");
       startActivity(intent);
   }
   

How to pass parameters to an application or know its capabilities:

1. List of Available Intents for Google Applications
2. List of Intents by 3rd parties @ OpenIntents