All of the code is in place, and you have a better understanding of multithreading and how callbacks can be used in a multithreaded environment. Yet, if you build and run your app and add a new movie, the rating won't be displayed yet.
The following are the three reasons why this is happening:
- The table view cell that shows the movie isn't updated yet.
- The network request doesn't succeed because of App Transport Security.
- Updates to movie objects aren't observed yet.
Let's solve these issues in order, starting with the table view cell.
Currently, the movie table view displays cells that have a title. UITableViewCell has a built-in option to display a title and a subtitle for a cell. Open Main.storyboard and select the prototype cell for the movies. In the Attributes Inspector field, change the cell's style from basic to subtitle. This will allow you to use detailTextLabel on the table view cell. This is where we'll display the movie rating...