Java Programming Tutorial - 75 - MouseListener interface Video Lecture

what is going on guys welcome to your
75th job tutorial and in this tutorial
we're gonna be going over how to handle
those Mouse events so in the first
tutorial we pretty much we built a
window so let's go ahead and go outside
our constructor right here and we want
to make a new class and let's go ahead
and make it make it private class and
you got to name it whatever you name it
up here so I named mine handler class
and then what we want to do is implement
from two other classes so implements
Mouse listener and it also implements
Mouse motion listener so hopefully those
errors go away and they did so now what
implement means is we have to use every
method that was in the class Mouse
listener and there are five methods in
this and Mouse motion listener and there
are two methods in this so what Java did
is they put methods inside Mouse
listener and Mouse motion listener to
automatically detect Mouse events so
whenever you move your mouse it's gonna
be registered in an object called an
event so let's go ahead and I'll just
start building these methods and you'll
see exactly what happens so the first
methods we need to implement are those
five methods for mouse listener and
these are mouse press mouseclicked Mouse
released Mouse entered and mouse exited
and I'm gonna tell you guys what these
do when I go through them but for now
let's go ahead and build our third one
first one so public void Mouse clicked
and what this does it is whenever you
click down the mouse and what this means
and I know you guys forever saying are
AI know what click means when you press
and release the mouse really click
really quick Wow embarrassing that is a
click now a mouse press and a mouse
release are two different things so you
know maybe guys then no equipment after
all but this is what Java defines a
click as so and all these parameters are
gonna take something called this Mouse
event event so you might as well just go
ahead and
copy that and copy that like that
because we're going to be using it a lot
later on so now whatever we type in here
is finally what we want to happen when
the mouse gets clicked so let's go ahead
and take that status bar and we want to
change the text on it so status bar dot
set text and what do we wanted to set
the text equal to well let's just go
ahead and put let's put string format
and in our format parameters it takes
two parameters itself and the first one
is clicked at percent D comma percent D
so it's going to say clicked at two
coordinates in Java also has two
coordinates based on this event right
here why do you have this event because
it registers the event like when you
click it decides where it clicked and
you can get to this the locations by
clicking event get X and also but guys
probably can't see this it's a little
better and also event dot get Y with
empty parameters so now whenever you
click this you get the x-coordinate in
the y-coordinate of where the event
happened and you guys can see this later
on but for now let's go to the next
event the next one's will be a lot
easier I just wanted to demonstrate that
you can get the x-coordinate and get the
y-coordinate and one of them but and the
rest of the methods I'm gonna make them
real simple so we made something that
happens when the mouse is clicked but we
need to implement the rest of the
functionality and the second one that we
need to implement is public void Mouse
released and this is what happens when
you release that mouse button so
actually let's go the second one is
Mouse pressed that people usually do so
let's go ahead and mouse pressed is what
happens when you press down that mouse
button so go ahead and throw your mouse
event event
in there and for the body let's just go
ahead and put something like status bar
set text this is gonna change the text
on our status bar to like you pressed
down the mouse so now this is what
happens that or excuse me the status bar
is going to pop up this text whenever we
press down the mouse and now we can get
the public void Mouse released and this
is the event of when the mouse releases
or after you press it down you let go of
the button so this is all easier see
with our program actually so let's just
go ahead and copy this now because we
are too lazy and it's going to say mouse
release so you release the button so now
we have three methods that we implement
it what happens when you click the mouse
what happens when you press and release
the mouse and believe it or not these
are actually three separate things I
know you think press and release is the
same thing as clicking but trust me to
Java it isn't so now in this class there
are two other methods that we need to
implement public void Mouse entered and
what this is gonna take is of course our
mouse event event first of all I can't
forget that taste that baby right there
that's what I'm talking about and what
Mouse entered means is this is the event
when the mouse enters the area in our
area is of course um where are you
mouse panel right here so this is what's
going to happen whenever the mouse
enters the mouse panel so remember up
here we put it at white by default so
now let's go ahead and change that
actually the first thing we can do is
click status bar set the text to
something like
you know you enter the area not bad and
now let's go ahead and change the color
of our mouse panel so mouse panel dot
sets background not bad ground set
background and what do we want to set it
to when the mouse enters um just put
something noticeable colored thread or
something like that I mean it's pretty
noticeable come on so of course you're
wondering all right you have a mouse
entered method something tells me that
you're probably going to have a mouse
exited method as well well if you guess
that then you would be correct so public
void Mouse exited make sure I didn't
spell excited I do that sometimes
because I myself get excited about this
method sometimes so you know it happens
so go ahead and type mouse event event
nothing new so what this happens
whenever the mouse exits the window
pretty much in essence so the first
thing we want to do is cyst status bar
set text and put the mouse has left the
window BAM
pretty much make sure you spell the
wrong make sure you put he instead
because I'm too lazy to fix it although
but easily could just fix it right there
anyways enough of that so now let's take
that mouse panel and whenever the mouse
is in the window it's gonna be read so
whenever we exit the window it let's go
ahead and set set background we'll just
set this to I guess white again I mean
why not make sure we don't got any
errors and we did it so all of these
five methods right here these are the
mouse listener events but again we
implemented for mouse listener and mouse
motion listener
lucky for us Mouse listener has five
methods which I already did and Mouse
motion listener which is on the
that the methods our mouse dragged and
mouse moved it only has two so this
one's gonna be a lot easier so in the
next tutorial we're gonna finish up
building this program and all we have to
do is implement these two methods Mouse
motion listener which are like I said
dragged and move and once we do that we
can finally run our program and see what
it does and it's gonna be awesome it's
gonna be amazing
but for now thank you guys for sticking
with me thank you for learning Java with
me don't forget to subscribe to my
channel and I will see you next tutorial