ChecklistActivity: When starting ItemDescriptionEntryActivity, the type of action is added as an extra in the Intent. Create a field to hold the tag, and use it in all applicable places to ensure consistency.
ChecklistActivity: Remove TODO regarding activity launch mode - no changes required
ItemDescriptionEntryActivity.onCreate(): In OnClickListener for OK button, just set result code once and make the variable final.
ItemDescriptionEntryActivity: Create new OnClickListener implementations that will take care of adding and editing actions. In the onCreate method, based on action type set the appropriate OnClickListener for the OK button.