JavaFX Java GUI Tutorial - 7 - Closing the Program Properly Video Lecture | JavaFX Java GUI: Learn to build Powerful Applications - Front-End Programming

alright guys welcome back and I know it
has been a few weeks but I've been busy
working on my android app for my site so
anyways I'm kind of at a little breaking
point right here so I'm ready to hop
back in the JavaFX and in this video I'm
going to teach you guys how to properly
close out of your application now you
guys are like all right I already know
how to close out of a just hit this
button and top right boom roasted
program is closed but here's the thing
whenever you're making an actual
application most of the time you want to
run a little chunk of code right before
the user closes out for example if
you're making a game you might want to
save like their position or their level
wherever they're playing maybe if you're
making like a chat program you might
want to save their history log
essentially you want to do something run
a bit of code most of the time so just
myself should always adjust myself
before I start these tutorials but oh
well alright so you got this idea that
maybe I'll show you guys what we have so
far so my starting point for this
tutorial is just a button and when you
click it nothing happens so we'll say
that okay how about if we have the user
click a button and then we can hop down
to you know some method that we build
saves a chunk of code then closes out
all right we can do that
so button set on action use those cool
lambdas and we'll make a method call
like a closed program so now we actually
have to build it so private void closed
program and we'll just say like
something like this so system.out.print
line we won't actually save a file
because it would just be a waste of time
but we'll have some pseudocode bag save
or I will say file is saved
all wise there was no file saved a
sucker's all right so after we read our
code to save a file or do it do whatever
we want to do inside this method we can
just call window close and this will
close the window for the users so run
and check it out
all right they're doing their thing
playing their game they decide to close
out so they hit this button closed
program and check it out the file was
saved this bit of code ran and the
window closed perfect but here's the
problem that we have already let me
expand this so say that the user is
using this program and they decide to
hit this button right up here well then
they just bypassed our entire method and
all of that work was for nothing
so what we decided to do is this what we
can do is we can actually on this window
we can call a method called set on
clothes request now this method gets
called whenever the user requests to
close the window in other words whenever
they hit this button then this method is
going to be called and what we can do
here is essentially the same thing where
whenever they request to close the
window we say ok well whenever you want
to do that just hop down here and we can
save a file that way so run this of
course we already know that closing it
through the button works fine and now
also closing it with this little close
button works fine as well so boom good
to go
tutorial done not quite there is one
more thing that I need to teach you guys
and that's is see whenever the user
kicks off to set on close request it
sets off an event to close the window as
you can expect so what that means is say
that we wanted to have a little dialogue
instead of saving a file that was like
are you sure you want to exit out of the
program you know like um most web sites
or a lot of websites do this whenever
you're filling out a form or some you
know software programs before you save a
file
they have a little alert box back are
you sure you meant to close and if the
user chooses no then you know they can
go back to doing whatever they're doing
so here is the thing let me close out of
here and I'll show you guys something
cool so let's go ahead and implement
that by making a boogly variable and
we'll just say that on our story
enhancer now using our nice little
confirm box remember we had a method
called display and this pops up a new
window and we'll just give a some stupid
title and inside here we'll say sure you
want to like exit or something like that
so eventually what's going to happen is
if they click yes then this is going to
be equal to true if they click no then
this is going to be equal to false so we
can test this variable and we'll say if
answer which pretty much means if I type
there right so now we're saying if they
clicked true then what we want to do is
we want to hit window close alright this
seems to be working good logic looks
pretty solid so check this out
so we're going to close the program
right here sure you want to exit
actually no I don't want to close it
sure you want to exit yes program closed
now check this out I'm going to do it
again but watch what happens whenever I
click this I'm going to click this close
button in the top right are you sure you
want to exit no I'm not accidentally
clicked it program closes anyways what
the heck is going on why did it work so
well with a button but not the window
because this method is being called both
ways well here is the thing in the one
last part I want to teach guys whenever
you call set on close requests remember
this is pretty much you telling your
system I want to close this program so
what's going to happen is it's going to
say ok first run this bit of code so
it's going to run this bit of code which
gives you an alert box now no matter
what answer you choose
once this is done remember it still
knows that you requested to close out of
the program so it's going to say okay
you chose an answer don't really care
the request is still happening you still
wanted to close so I'm closing either
way so it is in the case with the button
because we didn't request the close only
with the window sounds kind of weird but
this is how you solve this it's very
easy so instead of just letting that
close request go on its weight and
complete the entire thing what we need
to do is this inside we can just throw
it in our lambda right here and let me
put two alright so again we're still
going to call closed program but before
we hop down to this method what we want
to do is we want to take that event
which is the closed event and we want to
consume it now what this means is we're
pretty much saying okay the user wanted
to request the close but we're going to
consume that event in other words hey
Java we got it from here so consuming it
pretty much tells your system hey we're
going to take care of it and then when
it hops down here we can pretty much
implement our logic properly so we
already know that the program works fine
sure you want to exit nope and now since
we consumed that event pretty much the
closed event stopped and we're handling
it manually through our methods so sure
you want to exit no let's click again
sure you want to exit yes so there you
go that is how you properly close out of
application and all the little weird
things hopefully you guys understand now
and how you can run a chunk of code
brilliantly in your application so
anyways thing guess watching see you
next time