This element declares an activity existing in an application. All activities must be declared in the app manifest in order to be seen by the Android system. <activity> is always placed within a parent <application> element. The following code snippet shows the declaration of an activity within a manifest file using the <activity> element:
<activity android:name=".GameActivity" />
The name attribute in the preceding code snippet is an attribute that specifies the name of the class that implements the activity being declared.
