Improves doc for ActionType.

PiperOrigin-RevId: 621948044

android_env/components/action_type.py

@@ -13,14 +13,37 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""The different kinds of actions that AndroidEnv supports."""
+"""The different kinds of actions that AndroidEnv supports.
+
+The native action space of AndroidEnv consists of a tuple consisting of
+- A position (x, y) ∈ [0, 1] x [0, 1], determining the location of the action on
+  the screen, and
+- A discrete value, indicating the action type, which is in this file.
+
+See https://arxiv.org/abs/2105.13231, section 2.2 for details.
+"""
 
 import enum
 
 
 @enum.unique
 class ActionType(enum.IntEnum):
-  """Integer values to describe each supported action in AndroidEnv."""
+  """Integer values to describe each supported action in AndroidEnv.
+
+  Note for KEY* types:
+  - Only meaningful if connected to a _physical_ keyboard, _not_ virtual
+    keyboard.
+  - Added afterwards so they did not appear in the paper.
+
+  Attributes:
+    TOUCH: Touching the screen at a location.
+    LIFE: Lifting the (imaginary) pointer from the screen at a location.
+    REPEAT: Repeating the last chosen action.
+    KEYDOWN: Sending a key down event.
+    KEYUP: Sending a key up event.
+    KEYPRESS: Sending a key down event, immediately followed by a key up event.
+  """
+
   TOUCH = 0
   LIFT = 1
   REPEAT = 2