Adding the search feature

By leveraging the Movie Database web service search feature, we'll allow our users to search any movie by title. What we want to do is show a search icon button in the AppBar. When the user taps on the button they will be able to enter part of a movie title into a TextField, and when they press the search button on the keyboard, the app will call the web service to retrieve all movies that contain the user's input.

Let's add the logic that we'll use to implement the search feature and call the Movie Database web API with the title we want to search:

1. In the http_helper.dart file, in the HttpHelper class, let's declare a final String, containing the beginning of the URL required to perform a movie search. Obviously each API has its own URL structure, but most public web services have thorough documentation that will help you to...