ST EK List:
5.3.1K Lists and list operations, such as add, remove, and search, are common in many programs.
5.5.1J Basic operations on collections include adding elements, removing elements, iterating over all elements, and determining whether an element is in a collection.

Adding Contact Data

Purpose (do/learn; why this/here): Develop the user interface for adding list items and clearing (re-initializing) the list, which is helpful for debugging.

On this page, you will develop code for "Add Contact" and "Clear List" buttons in your contact list program.

  1. If it isn't open already, open your U3L1-ContactList project.
  2. Develop the "Add Contact" button for the user.
    1. Make the script ask the user for contact data and then add that data to the contact list using the contact constructor.

      2. Collecting Data from the User

      You'll want to ask the user for each piece of data (contact name, address, and phone number) separately.

      • You could use several ask and answer blocks together with script variables to request and then store each piece of user input until you are ready to report them all together using contact.
        contact with name: (name) address: (address) phone: (phone)
      • Another way that makes for cleaner code is to use abstraction: create helper blocks (such as ask name and ask phone) that each ask the user for one piece of data and report their answer to the contact constructor.
        contact with name: (ask name) address: (ask address) phone: (ask phone)
        Each of these helper blocks will ask the user a specific question (like, "What is the contact's address?") and then report the user's answer.

      You could first build a more general answer to prompt () helper block (yet another abstraction) to use in the other helper blocks instead of rewriting the ask and answer script every time.

    2. Test and debug. Add a few made-up people to your contact list. Make sure everything works.

    3. You can use these examples or make up your own:

    name address phone
    Betsy Anderson 123 Main St. #4, New York, NY 10001 212-555-1234
    Alphie Preston 149 E. 16th Ave., Sunnyvale, CA 94089 208-555-6789
    Gamal Abdel 369 Center St., Boston, MA 02130 617-555-1098

  3. Develop a "Clear List" button that resets the contact list to an empty list.
    1. Make the script ask the user for confirmation (so the user won't accidentally delete their list).
      For example, clicking, "Clear List" might ask the user, "Enter c to clear the list, or enter anything else to cancel."
    2. Debug. Make sure this feature behaves as expected for either user choice.
    4. Now Is a Good Time to Save
  1. The sprites' questions might be covered up by the contact list watcher on the stage. Use hide variable and show variable to hide the contact list watcher until the end of each sprite's script.