What's the difference between declaring an intent-filter in an activity vs. a receiver?

Question

I would like my application to be registered a handler for phone calls via the "Complete action using..." dialog. I've found that it works if I use the following syntax in my manifest:

   <activity android:name="my.class">
       <intent-filter>
          <action android:name="android.intent.action.CALL_PRIVILEGED" />
          <category android:name="android.intent.category.DEFAULT" />
          <data android:scheme="tel" />
       </intent-filter>
   </activity>

but if I register it as a broadcast receiver, my app doesn't show up in the "Complete action using..." dialog.

   <receiver android:name="my.class">
       <intent-filter>
          <action android:name="android.intent.action.CALL_PRIVILEGED" />
          <category android:name="android.intent.category.DEFAULT" />
          <data android:scheme="tel" />
       </intent-filter>
   </receiver>

What's the difference between the two apart from the type of class that's going to be called once an Intent matches the filter?

Answer 1

Difference is clear: the first one will try to launch an Activity, while the second one will execute a BroadcastReceiver. What to use depends on what you want to achieve; use BroadcastReceiver when you want to catch some event but do not want to show anything to the user.