JavaFX Java GUI Tutorial - 6 - Communicating Between Windows Video Lecture | JavaFX Java GUI: Learn to build Powerful Applications - Front-End Programming

alright guys in this video I want to
show you how to make a confirmation box
and what this is going to do is it's
going to demonstrate how you can have
multiple windows communicate with one
another
so in the last example I showed you guys
how to create a simple alert box you
click this button it opens up a new
window and the user can close it
whatever now that's great for simple
messages but say that that new window
that new pop-up was a settings window
and maybe it changed something in the
main program or maybe you gave the user
a choice or maybe like a confirmation do
you want to do that yes or no well
whenever they perform the action on that
pop-up you need a way to return data
back into your main program so right now
again what this did is a popped up a
window a completely new Island separate
from the main event they did their thing
and came back here but there was no
communication between the two so let's
go ahead and learn how to do that so I'm
going to make an entirely new class and
I'll just name it
confirm box and what this program is
going to do is just it let me rearrange
everything is it's going to be just like
an alert box but I'll show you guys but
instead of just popping up a window and
they can close it it's going to give
them two buttons I'll say like umm like
are you sure you want to send naked
pictures to your ex-girlfriend and I
have two buttons yes and no so they can
click either one of those and depending
on which one they click it's going to
take that and return it back here into
your main program so I don't know like
you can do whatever you want with it so
that's what this is going to do and of
course the main shell of it is going to
be really similar to alert box so we'll
just copy this for now and stick it
right in confirm box of course it's
giving us an error because this class is
not named alert box it's named confirm
box and our a so now we can get rid of
this and the first thing I want to do in
confirm box is just clean
everything up here these comments and
we're going to have that label still and
this is remember a button to close it so
we don't need that anymore because
that's not what this program is going to
do and also all right so we pretty much
have and make sure everything looks good
alright so right now this pop-up is just
a blank window with a little bit of text
in it so the text will of course be your
message like are you sure you want to do
that um maybe I don't know just whatever
you want to ask the user so again what
I'm going to do eventually is I'm going
to make two buttons and one of them is
going to be yes and one of them is going
to be no or you can make them true or
false whatever but we need a variable a
boolean variable to store that answer so
I'll just say um there actually I don't
even need a comment this is really easy
so static boo lean I'll say answer
so we'll actually make that program and
say are you sure you want to send naked
pictures to your girlfriend because I
don't know why not it's funny so we
first need to create two buttons get
myself a little bit more room alright so
first button will say that this is the
yes button so whenever they click this
we want it to return true and text for
this would just be yes and copy this
because you know I don't have like four
seconds to type the word button and
we'll call the second one no button in
the text on this will just be no might
as well capitalized so this might look a
little bit better alright so we have two
buttons now after this we need to add
some functionality so for the yes button
what we wanted to do is we want to set
on action right here now remember
whenever using lambdas if you just have
one line of code like
system.out.print then what you can do is
you can just stick it right here on one
line it'll work fine however if you ever
have multiple lines of code that you can
run what you do there is you stick them
in between curly braces so essentially
this is um a really quick way of like
making a method and your method body
just like any other method goes in
between curly brackets or curly braces
whatever you want to call them so what
happens whenever the user clicks the yes
button well the first thing we want to
do is we want to set the answer variable
to yes so answer whoa easy cursor set
this equal to true not yes tomato
tomahto
and after that after they click the
button then all we're going to do is for
the window which is the pop-up window
we're going to close it and we can just
copy this and do the pretty much the
same thing for the no button so the no
button is going to work really similar
so whenever they click the no button of
course the answer then is going to be
false
well you close the window as well now of
course we need to add the buttons to the
layout so yes button and no button boom
good to go now one other thing we need
to do is this right here we created a
variable to store the answer right here
we said whenever they clicked one of the
buttons then we're going to set the
answer variable equal to either true or
false depending on which button they
click now after this display method this
is actually not going to return void
this is going to return a boolean
variable this answer right here and it's
giving us error because the same all
right
when all of your little pop-up program
is done running you actually need to
return that answer so we're going to
return answer which at this point in
time is going to be equal to true or
false
so now if we go in what would I do this
is from the old tutorial
all right now what we can do is we can
call confirm box display and we can just
pass in title of window before and we'll
say are you sure want to send naked pics
all right good enough so remember what
this method does is it not only creates
this pop-up box but also whenever they
close it it gets their answer and it
returns it to you
so instead like before whenever we just
use a static method call we actually
need to take the results of this and we
can store it in variable so now whatever
this returns we're going to store in the
variable result so you now have that
data passed from one window to another
and from here you can do whatever you
want with it for this little demo I'm
just going to print it out so
system.out.print line result so again
this is just going to print out on my
little command line so let me run this
hopefully if it works
all right so click me it will launch
confirm box are you sure you want to
send naked pics yes closes it and check
it out it returns true same thing with
false when you click no I'm going to hit
no and it outputs false do it again boom
check it out so that is how you
communicate from one window to another
again if you just want a little I don't
know like alert box a little message you
want to display you're probably going to
use a class like this however if you
ever want to get input from the user and
pass it along into your main program
you're going to want to use confirm box
so there you go pretty simple once you
break everything down and yeah hopefully
you guys enjoyed and by the way if
there's anything specific you want me to
cover regarding JavaFX
then let me know and I'll make sure to
make a tutorial on that but anyways
thank guys for watching see you later