How to bullet-proof an intent via verification of existence of app to handle it ?

Here's a complete example that shows how to create an intent to view a map, verify that an app exists to handle the intent, then start it:

// Build the intent
Uri location = Uri.parse("geo:0,0?q=1600+Amphitheatre+Parkway,+Mountain+View,+California");
Intent mapIntent = new Intent(Intent.ACTION_VIEW, location);
// Verify it resolves
PackageManager packageManager = getPackageManager();
List<ResolveInfo> activities = packageManager.queryIntentActivities(mapIntent, 0);
boolean isIntentSafe = activities.size() > 0;
  // Start an activity if it's safe
if (isIntentSafe) {
    startActivity(mapIntent);
}