Java Programming Tutorial - 70 - JList Video Lecture - Java Programming

what's going on guys welcome to your 770
a--the there we go
Geoff tutorial and this is ro we're
going to be going over something called
Jay list now what Jay lists is is it's
pretty much a list for your GUI and when
you click on one of the options we can
make an event happen such as in this
case switching the background color so
let's go ahead and get started if you
can't tell I imported one more thing
here so make sure you have all of your
imports right here if you need them
pause the screen but you're probably
don't so I'm just going to go ahead and
minimize those right there and now we're
good to go
the first thing we're going to need to
do is make a variable for that Jay list
so let's go ahead and make private Jay
list because that's what type it is I'm
going to name my list for simplicity now
after this what program we're going to
be making is we're going to have a list
of colors and when you click on one of
those colors it changes the background
so we're going to have two arrays one
for the color name and one for the
actual colors himself that the computer
can recognize so one that we can
recognize and one the computer can
recognize so let's go ahead and make our
first array just the color names that we
can recognize so it's going to be
private static string it's just going to
be the names of the colors and just name
it color names and we'll set it equal to
let's go have a color like black blue
red and white I have four colors inner
lists can have more if you want but I'm
just going to have these basic ones and
make sure to put them all in quotation
marks like this and then and your line
with a semicolon BAM you're good to go
so I have four color names in our first
array called color names now the second
thing I want to do is build an array of
colors that the computer can understand
so go ahead grab it static again I'm
going to name this array color or excuse
me it's going to be of the color type
and I'm going to name it colors and in
this list we're going to put the colors
in the way that Java sees them and
that's this color dot black all in cat
so that's how Java sees colors or
recognizes them it's from the color
class and then you write the name of the
color all in caps and our next one's
blue so color the blue all in caps and
our next one's red so color dot thread
all the caps and color the white so now
we should be good to go looks like
America in any airs and now let's go
ahead and we have our three variables
pretty much list coloring names and
colors we can go ahead and build our
constructor or window so go ahead and go
to your instructor and it's not going to
take any arguments just go ahead and do
some housekeeping stuff add the title
and where you at curse oh got the
hiccups and embarrassing and next thing
you want to do is set the layout and
just going to set this to normal flow
layout by putting new flow layout I
wonder why they capitalized the F in
that one pretty weird and don't forget
your empty parameters so now I have a
title in the layout now we can go ahead
and start messing with our list the
first thing we want to do with our list
variable is actually create something
and what we need to do is create a new j
list and the parameter J list takes is
an array of what you want the person to
see and we want the person see the color
names is the options so let's go ahead
and just write color names in here um
you don't need it in like quotation
marks or anything like that so now we
have a list and it pretty much is just a
list of color names what we want to do
now is set how many rows are pretty much
the height of the list so go ahead and
take that list and put set visible Arial
row count right there to easy and what
this is is how many options the user can
see by default now if you put like they
can only see four but there's like ten
items in the list a little scroll bar is
going to appear on the right but since
we only have four and we put four then
it should fit just perfect
um the next thing you want to do is go
list set o it's called selection mode
there we go right there set selection
mode and for the perimeter it takes is
this some lists allow you to select one
thing or another thing and some lists
allow you to select multiple items the
one we want to use is we only want to be
able to have a single selection at a
time so we're going to have as a
parameter list selection model dot
single underscore selection just like
this and now instead of like cooking
control and selecting many things or
shift the user can only select one thing
in the ERR list at the time so now the
last thing we need to do since we got
our list all made is just add it to the
window or well yeah that's all we need
to add it to the window so add new j
scroll pane and of course we want to add
our list to here and now we added our
list to the window pretty much so in the
next tutorial we're going to be adding
some functionality to this list and it's
a little different than the other
tutorials I'm only teaching you
something even newer and easier in the
next tutorial but for now thank you guys
for watching don't forget to subscribe
and don't forget to check out the next
tutorial so I'll see you then