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

Question

I understand how to use intents and startActivity() when opening another activity within my own app, but how do you start a different app? specifically:

• How do you determine if the user has the needed app installed on their device?
• How do you start that app?
• How do you pass parameters to that app?
• How do you find all this info out for a specific app (say Adobe reader, or google maps)?

Answer 1

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