Java Game Development - 28 - Intro to Keyboard Input Video Lecture | How to create Games in Java - Gaming Development - Software Development

what is up guys welcome to your 28th
java game development tutorial and in
this is aura we're going to be finishing
up this core class which is pretty much
all the code that we reuse over and over
so we don't have to keep typing it over
again and we're going to be building two
methods update and draw now two things
about these what your update method in
your drama that are going to be unique
every tutorial pretty much so instead of
filling these with the useless code
we're going to overwrite them every time
we use this class so we're pretty much
all we have to do is make the method
headers and we don't need to put
anything in the body form so it's
literally going to take about 14 seconds
to do so update animation and just name
this public void update and you're going
to need to pass in long time passed and
all you have to do here is add an empty
body just like that actually take that
line out of right there and that's all
and since we have to be um use this
method whenever we inherit all we have
to do is fill in the body of this and
since you don't really know where you're
updating you just know that you're going
to have an update method that's why we
need to do this and the next one is just
the same our draw method draws to the
screen and public abstract void draw and
as a parameter takes graphics to D and G
and we don't even need a body for that
so let's go ahead and let make sure I
didn't miss anything up no errors or
anything so this pretty much you should
know what all of this does already
I just want to type it out for you guys
in a tutorial er too so you guys can
just copy it and see what I'm working
with so this is the code that we don't
have to type ever again thank God we
just have to type it this one time and
we can just inherit it from now on so I
go I went ahead and let's get to the
meat of this tutorial I went ahead and
made another class right here called key
test to demonstrate what I'm going to be
teaching you
and that's how to get keystrokes or
events from the user now as you can see
instead of having to type all that code
again I just extends core which means
inherits from this core Java and now
inherits everything in here how awesome
is that so now the only other weird
thing I did is I did something that says
implements key listener now what a key
listener is is whenever you need to get
information from the user you have to
put a listener on something and what a
listener is it says all right wait for
an event to happen so we're going to be
adding a key listener to a window and
what this window is going to do is it's
going to wait for the user to press a
keystroke on their keyboard or our way
from click a mouse or wait for them to
do anything and that's what listeners do
they pretty much just wait listen for
you to do something and whenever you do
something it runs a bit of code for you
so you'll see later on but that's why I
said implements key listener that's what
we're doing we're implementing a
listener or making our computer wait for
something to happen and if you're
wondering why this is underlined key
listener has three methods in it that we
need to implement since uh while we
implement it from it so let's go ahead
and do that right now well not right now
but in a little bit so you already see
that I called this run method so that's
what we're going to be doing first after
we make a couple variables private
string mess for message in this set is
equal to nothing by the way the program
that I'm building all we cool someone's
alarms going off outside that's not
going to be annoying at all
oh good stop all we're going to be doing
is we're going to be typing a letter on
our keyboard and when we type it it
draws on the screen and says like you
press S or something and when we really
release it it's going to print out on
our screen
your release S or something but it's
just to demonstrate how you can actually
send information to your game and get
some information
and later instead of just having stupid
words we're going to be moving around
images and stuff like that but once you
see how key listeners work and stuff
like this it's going to be really easy
to move forward so let's go ahead and
I'm just going to make this string
variable that's what's going to print
out on our screen we don't need to set
to anything yet be set because we didn't
do anything yet now for um actually
let's make something like in it this is
going to be my init method but it's also
called init from super class so this
method right here is going to be public
void in it and usually if you already
created method this would override this
method this init Varya in it right here
but what we want to do first is we want
to call this method specifically so in
order since we inherited from the
superclass right here how can we call a
method from the superclass anytime you
want to specifically call a method from
the superclass what you need to do is
that is put super dot and then the
method name and in this case it's in it
and if you hover over this it says for
dot or dot in it so that means you're
calling in it not only this one from the
key test class but from the superclass
called core so that's how you do that
next in our initializing method we need
to create our window object and our
window object is this screen dot a get
full screen window just like that pretty
cool and now we need to do a couple
weird things but we definitely need them
W set focus where you focus are right
here traversal keys enabled and we want
to set this equal to false now let me
explain what this means set focus
traversal keys enabled a long method but
does something really easy whenever you
type like how can I explain this
whenever you're on a website and you
press like tab you know that it doesn't
just type out something
it does something weird like it moves to
the next forum field or maybe if you're
on your window and you press tab it
moves all around objects what we want
this to set tab to is pretty much don't
do anything weird like that just be a
tab button like every other button why
can't you just be normal tab button so
this pretty much says make all your
weird buttons arm weird and if it was
true there'd be weird still but we want
false and that just makes your buttons
like tab act like normal buttons and
after this what we want to do is add
that key listener so a key listener you
can put on pretty much any object so but
we want the window to listen for keys so
whenever we're focusing on our window
that's what's going to be waiting and
hat and waiting for things to happen so
W dot ad key listener and as your
parameter you put what you want to add
is your key listener just go ahead and
put this and that will make your window
the key listener so you can put it on
different things but we want the window
to wait since I mean that's the only
thing I really can do for now and after
this after we have our key listener took
care of all our weird stuff we need to
set a message to draw first so what
we're going to do is in order to exit
this program we're going to use the
Escape key we're going to do something
weird with that so press escape to exit
and later on we're going to do something
weird that says alright whenever the
user presses the Escape key instead of
doing what our program regulary of those
we want you to stop the entire program
and exit so that's pretty much it for
this tutorial that's all the time I have
but for the first thing we had to do
when you run the program initially is
pretty much call our super classes
initialization function create a window
that's pretty much equal to what you're
looking at the full screen we want to
take all the weird methods off of tab in
stuff like that we want to add an object
so when we press a key something
actually
actually is waiting for it to happen and
if we don't add a key listener to
anything we're just going to press a key
in your computer's going bug odo I don't
know what's that going to happen now we
actually have did I just delete that all
Teddy seriously just delete that and now
since we have a key listener we actually
have this window waiting for something
to happen so it can actually get that
information of what key oppressed and do
something with it so that's what that
does and we added it to this which is
pretty much the window and we gave you a
message by default on the screen we
didn't need to do this but it's nice to
know it's nice to see something when
you're first starting out so in the next
tutorial we're going to be learning how
to make key presses and key releases and
stuff like that so thank you guys for
watching don't forget to subscribe and
I'll see you next tutorial