Java Programming Tutorial - 50 - Graphical User Interface GUI Video Lecture

what is going on people welcome to your
50 Jeff tutorial and I know it's been a
while since I started making Jeff
tutorials but hey we're going to get
back on track and start learning some
more Java so actually I had planned out
that we're going to learn polymorphism
but I think I'm just going to skip right
to GUI is because it's a lot funner and
it's better if we know how to make an
interface before we start getting into
some other stuff plus one we have an
interface and stuff you can see what
everything does and you're not just
typing random code that you're like all
right what is this the matrix because
you know it's time we started building
an application that the user can
interact with in C so if you don't know
what a GUI is or some people call it a
GUI it's a graphical user interface and
just like this right here it has title
bar at the top menu dropdowns has a
whole different range of buttons and
that's what we're going to be making
instead of this right here where it's
like matrix style because I mean come on
it's 2009 if you're watching this story
on 2009 that is so let's go ahead and
get started now the first thing you need
to know is that all gooeys are built
from GUI or GUI components that means
there has to be a component for a menu a
dialog box scrollbars you have to add
each one of those individually so how do
you just go ahead and get these
components well actually Java has built
in a class that stores all the
components you need you just need to
tell it where to put it and what to do
with it and they are created using
different methods in the methods used to
create this in the class it's called the
J option pane class now like I said this
class is built in the Java so anytime
you want to make a button all you need
to do is call it from the class and
there are different ways to do this but
this is the easiest way so in order to
get all those buttons and toolbars in
everything we first need to import the
entire
class so let's go ahead and before your
evening class right here just go ahead
and put import Java X dot swing dot J
option pain and make sure you type the J
in the o capital option paint and just
like that and now we're getting a little
error that says on the import Java Japs
from pains never used so let's go ahead
and fix that by using some stuff right
now so now we imported the class which
means we have access to all the crap in
it so let's say we're using something
that career the first thing we're going
to want to do is set to variables by the
way I'm going to build program where you
enter a number in one box and then click
OK you enter a number in another click
ok in the end box
the third one shows your answer you're
seeing a little bit so we need to set
this equal to string variable and set it
equal to first number and I'm just going
to write m then R excuse me FN for first
number now what you need to do is called
the class which is J option pane use
your period or dot separator in the
method for an input dialog is show input
if you can't tell by these hundred
pop-up things that pop-up dialog and
it's going to take one parameter right
here and this is the message now what
this is is the message or the prompt
which you want to tell the user to do so
we just want to put in a string enter
first number so now whatever they enter
into that first number is going to be
stored in variable FN so now we need a
second number so let's go ahead and copy
this press ENTER paste it and let's just
set string second number and we'll just
put ekit enter second number right there
make sure I got my whatever it's called
semicolon and let's go ahead and move
this over here because just because I
feel like it now here's a little thing
that you need to know every time they
enter something in here show input
dialog method only is able to get a
string
so we can't add strings strings are
pretty much letters in numbers that it
doesn't see as a number so we need to
tell Java all right instead of viewing
this as a string we want you to view it
as an integer so you can do some math
with it later on so what we need to do
is convert these variables to integers
so this has nothing to do with them
J option pain this is just Java right
here so Java num or excuse me int num1
equals its Jerk dot parse int and what
this does is convert whatever I type
into here in stores is an integer in
num1 so I want to put FN and what this
does is take the string which say it's 5
and converts it into the number 5 so now
let's go ahead and do this for num2 num2
we want to take the second number we
typed in and convert it to a variable
called number 2 so now the last thing we
need to do is just show the sum so
before I even do that let's just add the
sum in sum equals o to put num1 plus
num2 no spaces and now we got the final
answer in the sum variable right here
let's tighten that up a little bit
that's what she said and now we can go
ahead and display this now the box that
you used to display is something called
show message dialog so let's put J
option pain the show message dialog and
this is a little different than show
input dialog inputs for inputting
messages for displaying now this method
takes 4 parameters the first one is it's
a parameter where to position it and if
you put null positions at right in the
middle of the screen the second one is
what you want to say like for your
prompt but isn't prompt it's just a
message so let's put the answer is and
let's just put add some so it's going to
be like the answer is 5 or something
like that
now the third parameter is what we want
to appear on your title bar so let's put
like the title or something something
easy like that and the fourth parameter
you need is the message that's going to
pop up now I'll go over this later if I
got time but for right now just put J
option was a pain then put plain
underscore message like that and you
don't need to put this last thing in
quotation marks so again well that's
pretty much it let's just go ahead and
run this program
tire waiting around so let's go ahead
click OK run it enter your first number
three okay
enter your second number five okay the
answer is eight and now I can talk you
through this one more time so now once
we go ahead and run this what we're
getting is this very first thing the
show input dialog and it says enter your
first number and we're going to go ahead
and enter four press ok now once we
press ok it stores that four and F n
variable right there and also it allows
us to move on to this other show input
dialog it doesn't move on until you
complete the show input dialog so under
your second number six okay so now what
it did right here is it took that four
and convert it to number and took that
six and convert it to a number so that
you can add the two sums right here and
lastly it took that show message dialog
which if I can get it back right here
and it says that know what main position
in the center of our screen the answer
is some right here and again that third
parameter was the title which appeared
on the title bar
and that last one you have the option of
putting icons on your um GUI or user
interface that we built but we're not
going to put like ons on here now mostly
could because they're stupid um if you
want to have
something like an error you can put X on
there a warning you put it like a I
don't know they're stupid but we'll
probably put them in next time because
I'm stupid too so but that's a real
quick tutorial on how to use J option
pain to make a simple graphical user
interface
aka GUI so in the next tutorial we're
going to be building our gooeys and atom
some more function ask more cool buttons
and stuff like that so thank you guys
for watching don't forget to subscribe
and I will see you next tutorial