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

Answer 2

What you are looking for are intents and intent filters .

Everything you want to know is detailed on the Android developer guide.

http://developer.android.com/guide/topics/intents/intents-filters.html

Answer 3

This works for me:

Intent launchIntent = getPackageManager().getLaunchIntentForPackage("com.example.testing_app");
if (launchIntent != null) {
    startActivity(launchIntent);
} else {
    Toast.makeText(MainActivity.this, "testing_app is not installed", Toast.LENGTH_LONG).show();
}