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Displaying a Menu
3:57Our users will need a way to interact with our program. In this video, we begin to offer that functionality by displaying a simple menu and waiting for input.
[MUSIC]
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Now that we have most of our classes set
up, we can work on input and output.
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We're going to use a class from the Ruby
Standard Library to save things between
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sessions.
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This is a lot easier than you think.
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Let's go ahead and
see how that works now, using WorkSpaces.
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Okay, so we have our functionality
with our address book working so far.
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We can add contacts.
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We can add phone numbers and
addresses to our contacts.
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And then, we can go ahead and
search through it if we want to.
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So now, we're going to make this
more of a command line application.
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So what that means is
we're going to have a menu
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allowing our user to select something and
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then work with it in the command line,
rather than from inside of a Ruby file.
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Now the way that we're gonna do this
is create a method that loops through,
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displays a menu and
then will call each of these methods,
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depending on what the user enters.
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So let's go ahead and create that.
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Now, before we do that, let's go ahead and
look at all this stuff down here.
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We're gonna just go ahead and
get it out of there.
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So we have this address
book that we initialize.
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And let's make a method called run
which will display our menu on a loop.
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And that's all that we're gonna do to call
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this run method which
will display our menu.
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So now let's go ahead and write that.
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Here is our run method.
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Now we're gonna use a loop,
to display our menu.
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And we are going to need
a way to exit the loop.
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But, we'll write that in just a second.
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So for
right now let's just display address book.
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And let's go ahead and
give an option here.
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If somebody enters
the letter E they can exit.
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So we've got this little menu here.
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This is just the start of it.
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And then let's go ahead and
ask for their input.
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We'll say, Enter your choice,
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and then we will grab the input and
assign it to a variable.
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We'll use the getString method, which
we'll just grab it from standard input.
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And that will go in with a new line.
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So we have to use the chomp
method to get just the character
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that we're interested in.
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And then let's go ahead and just make that
lower case so that when we search for
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it we know what's going on.
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Okay, now we know we're gonna
add on to this later, so
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we're going to use a case
statement right now.
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Since all we have is one option,
we're just gonna have one single option
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in this case statement,
so when the user types
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the letter E,
we're gonna break out of this loop.
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Now let's go ahead and
ruin this and see what happens.
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Address book, okay, let's type
the letter e and make sure it exits.
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Uh-oh.
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Undefined method input for address book.
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I forgot an equals sign.
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Okay, let's clear the screen and
run that again.
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Okay.
Exiting works just fine.
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Let me clear the screen.
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We'll run this again.
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If I type a,
okay we just get this menu again.
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DE2, whatever.
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Okay.
Good.
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Now we know that E exits.
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This is a good start for our menu so
we know that it's working.
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