In the exercise S02.03-Exercise-Polish I believe that in activity_forcast.xml there should be TODOs inserted at after 3 and 13 to add an id to the TextView and ProgressBar.
<!--TODO (2) Add a TextView that you will show the user if there is an error loading content-->
<!--TODO (3) Make the width and the height wrap_content-->
<!--TODO (4) Give the TextView a default error message stating that an error occurred (use strings.xml)-->
<!--TODO (5) Set the default visibility of the TextView to invisible-->
<!--TODO (12) Add a ProgressBar to show the user content is loading-->
<!--TODO (13) Make the width and height of the ProgressBar 42dp-->
<!--TODO (14) Set the layout_gravity of the ProgressBar to center-->
<!--TODO (15) Set the default visibility of the ProgressBar to invisible-->
I am not sure if this is done on purpose for course reasons to get students to figure it out on their own, but in other lessons this is included in the TODOs. Also it is necessary since in the MainActivity.java you must reference these by their ids.
In the exercise S02.03-Exercise-Polish I believe that in activity_forcast.xml there should be TODOs inserted at after 3 and 13 to add an id to the TextView and ProgressBar.
I am not sure if this is done on purpose for course reasons to get students to figure it out on their own, but in other lessons this is included in the TODOs. Also it is necessary since in the MainActivity.java you must reference these by their ids.