Java Programming Tutorial - 72 - Multiple Selection List Video Lecture

what is going on guys welcome to your
72nd Java tutorial and in this story I'm
going to be teaching guys had build a
multiple selection list and in the last
tutorial you guys learn how to build a
list with a single selection or in other
words you can only select one item at a
time but in this tutorial I'm going to
be building a program where there's a
list on the left where the bunch of
items and there's a button in the middle
and when you select a bunch of items on
the left and click the button it moves
it to the right so it's going to be a
pretty cool tutorial and actually the
cool thing about this tutorial is all
the hard stuff we need to do is already
built into Java so I just need to teach
you the methods so let's go ahead and
get started make sure you have all your
imports right there I'm going to go
ahead and minimize that and now let's go
ahead and start making some variables we
need to lists and a button to start out
so private Jay list in the first list
I'm just going to name left list since
this is going to be on the left hand
side and I'm going to make another one
identical to this but I'm going to
change can't keep talking I'm going to
name this right list since this is the
list that's going to be on the right
hand side so now we've made two
variables for left list and right list
and they're both two J lists so now
let's go ahead and just make a button
private J button and I'm just going to
name my move button because that's what
it's going to do it's going to move this
stuff from the left to the right it's
actually going to copy it but you know
what's the difference now of course we
need an array or pretty much items to go
in our list and I'm just going to have
it private static and I'm going to have
a string because you know she's going to
be names and I'm going to have foods you
can have anything you want it really
doesn't matter but foods sounds
something I can it'll be interesting so
let's go ahead and type the foods I like
which is of course bacon and let's see
what else
wings had some last night they're
amazing bone sucking sauce look it up
ham and
let's get like two more beef I don't
really really like beef all that much
but I like the name of beef and that's
the important thing
and the last thing of course more bacon
and let's go ahead and end this so now
we have an array called food and
actually name that foods because I mean
it's foods bacon wings ham beef and more
bacon now make sure I got that and so
now we have the four variables we need
for this tutorial
left list right list the button in the
array so now let's go ahead and start
well I guess we can go ahead and start
building our constructor so public GUI
of course it doesn't take any arguments
and let's go ahead and add a title first
called super just name it title and make
a layout next so set layout and of
course nothing new here we're going to
get new flow layout with empty
parameters and now let's go ahead and
start editing that list on the left the
first thing we need to do is populate it
with the foods so it's new jlist
and any time you use a j list it takes
the argument of an array or in other
words what items do you want to put in
it so we want to put those foods in it
so let's go ahead and put foods in it
BAM a little too easy
the next thing we're going to want to do
to left list is if I spell it right is
add the visible row count so set visible
row count and make sure BAM look at that
how easy is that
so how many of these items do you want
to see by default and I want to see
three items by default so now that our
list is five items but we can only see
three what we need to do is add
something called a scroll pane that
we're going to add later on right now
left list dot set selection mode right
there too lazy to type it and go ahead
and and this statement and our selection
mode unlike before it's going to be list
selection model not Mosel model dot
right there multiple selection and what
this means is unlike last time where you
can only select them one thing at a time
with multiple interval selection using
your ctrl + Shift keys on your keyboard
you can select multiple items at a time
using this so now the last thing that we
need to do to our arm left list is add
it to the screen and also like I just
told you guys before we need to add a
new J scroll pane right here and what
this allows you to do if we add the left
list eventually is it allows you to have
a list bigger than default viewing and
it pretty much just put a scrollbar on
the list that's what I'm trying to say
it pretty much puts a scrollbar
on your list so now we did our left list
so now all we need to do now is make our
move button and write lists so go ahead
and click move button and set these
equal to nu J button and make sure you
have a space in between there and the
parameters frist
is the text you want to appear on the
button so I'm just going to have move
and a little arrow just like that so you
know that we're moving from the left to
the right so now we can go ahead and add
action listen or listener of other words
functionality to this move button so
move button dot add action listener
awesome and of course this is going to
have an inner class because it's a lot
easier so inside your add action
listener parameter just go ahead and
make a whole new class called new not
boo new action listener just like that
and this class of course doesn't take
any parameters and inside your new
action listener inner class we want to
have one method and if you can see by
our air it's called action performed so
let's go ahead and add public void
action performed make sure I spelled it
right PR fo r m e D looks good and as
your parameters for this just right
action event event BAM this is a little
too easy that's the only problem with it
now we can finally get to the good stuff
of what we want to do again this is all
default stuff that you need that's how
did they just made the program but now
we get the custom stuff what we want to
actually do well the first thing we want
to do when we click the move button is
build our write list we've already built
that left list but the right list
depends on what we select in left list
so go ahead and type write list da and
the first thing we need to do is set the
list data or set the things we want in
the list so go ahead and set list data
and what this does is it takes an array
is its argument just like let's see
just like J list took an array as its
argument set list that is also going to
take an array that's its argument to set
the list data so how do we get an array
of selected values from a left list well
this is another cool thing just go ahead
and type the left list dot get selected
values right there how awesome is that
get selected values and what left less
dot gets selected values those is
whenever you select stuff on the
left-hand side of your screen or in the
left list it makes an array of those
selected values and that array is going
to be passed into set list data and
essentially is going to create a list on
the right-hand side depending on what
you selected on the left hand side how
cool is that we don't have to make a new
method for setlist data we don't have to
make a new method for get selected
values everything's already built in
method so that is you know it's just
awesome so now that we made this button
and we added some functionality to it
let's go ahead and do one last thing and
of course we need to add it to the
screen so let's just go ahead and click
add move button and now our move button
is added to the screen
so in the next tutorial we're going to
be finishing up this program and
actually on building a write list and
you'll see what I mean in the next
tutorial so for now I guess I'll see you
next time thank you guys for watching
don't forget to subscribe and I will see
you soon