Android Application Development Tutorial - 74 - MotionEvents and Motion

what's up guys welcome your 74th Android
tutorial for the young buck also known
as the new Boston or Bucky what we're
gonna do now is I decided to do a few
more graphics ones just because on my
channel a lot of people have been
wanting to do game animate our game
stuff and graphics and all that good
stuff so what I'm gonna do is basically
nothing too new but we're kind of kind
of review and this is what our
application finished product is going to
do is basically when you click it starts
and it creates a bitmap right at our
starting point and as we hold down our
mouse we let go and it also does another
plus right our endpoint so that can be
kind of useful to see how like you know
if you're launching this ball we can get
those two points and use the velocity to
you know launch the ball a certain speed
over time so that's a zit that's
essentially what we're gonna get to but
yeah I just wanted to show you guys the
end result before we actually get into
it so so you guys kind of can kind of
follow along along and what we're gonna
do is we're gonna set up some more
floats for float variable variables SX
for starting X point sy for starting Y
point and then FX for a finishing next
point and FY for our finishing Y point
and again all we're gonna do is just
kind of set those all equal to be 0
right at the beginning because we're
gonna kind of use the same layout here
so let's do that real quick thought
that'd be a shortcut but it really
wasn't that much of a shortcut there so
so nothing new yet nothing you knew yet
but basically I want to show you guys
what we can do with a motion event
because we did kind of use it but we
didn't really get into too much so what
we're actually gonna do now is set up
our bitmap first so let's scroll down to
where we set up our our first bitmap
called test let's actually cut that test
out of our four out of our if loop right
here and define it within our on create
method so I'm just gonna paste that up
here hit control V and you know we
defined this bitmap we're also going to
want that bitmap to be accessible to
both classes that we have set up so
going to set up a bitmap variable called
test and then we're also going to call
one plus that's going to be the plus
symbol that we're going to use and then
we just need to delete again this bitmap
here and I'm just going to again copy
this line of code I'm kind of going all
over the place but hopefully we aren't
doing anything new yet for the most part
and set up a plus bitmap all we have to
do now is change the resource here to
our plus image that we have in our
drawable folder so there we go we have
all our bitmaps and all of our initial
points set up now let's go back into our
on touch method and this is where we're
going to kind of define you know our X
in our starting X and our starting Y
but first what we're going to do is
we're gonna use a switching case which
again we're familiar with we're gonna
get kind of the information from the
what type of motion event it is so we're
gonna say switch and then we're going to
say event because again that's the
motion of in set so that's being passed
in we're gonna hit dot get action and
that's gonna tell us what kind of action
is happening at the current moment
because we have this as true so it's
going to keep looping through for pretty
much every moment and then we just need
to do a bracket as well and set up our
cases so we're gonna say case then we're
gonna refer to the motion event class
and then we can hit dot and we have the
events that can happen so down is right
when we first click so what we're gonna
do with in this case we're gonna set up
our starting X our start X and then it's
just going to be again equal to event
dot get X you can kind of review here
and then also our starting Y and that's
going to be event dot get Y and there we
go and then all we have to do is say
break here and then we're gonna set up
our other case which is going to be the
release so we're gonna say
motion event dot you know action
reaction up so type that out and that's
when we're going to let our finger off
of the screen and then we're going to
set up our final X and what this is
going to be again event dot get X and F
Y our final Y is going to again be event
dot get Y so there we go we're gonna
kind of have these different x and y
values this one's going to be
consistently updating this one's gonna
be right when we press down and this
one's gonna be right when we press up so
let's just put a break there as well now
that we have everything set up we're
gonna go back within our canvas and
we're gonna kind of set up some more of
these if statements that we did
previously so I'm gonna copy three of
those because again we're gonna say one
is for our starting X if it's not equal
to zero and our starting Y is not equal
to zero and then we're also going to do
our starting our final Y and our final X
here hopefully this tutorials not too
long but I mean it's pretty simple and
this these this speaking too fast here
instead of our test we're gonna do our
plus bitmap that we set up at the
beginning that tutorial for both of
these and again what we're gonna do is
we're gonna get the bit the you know we
can still use this kind of equation
where we take half of the width and
subtract that from our final X so it's
kind of placed right in the center as
well this will be our starting X for
this one and again our plus bitmap we're
gonna get half of half of the width even
though both of our plus and our you know
our test or bill 75 pixels by 75 pixels
but you know that's besides the point
um and then again we say starting X and
starting Y so we're gonna say starting Y
minus plus I mean half the height as
well and then we're gonna do our final Y
and again minus half
the the plus height there we go I mean
we're done
basically this tutorial mainly just went
over the different types of motion
actions that we can get again we use the
switch case to get the action of what
type of event it is we set up the cases
to be either down or up and then when we
save it and hopefully run it we won't
get any errors it's pretty quick
tutorial but hopefully you guys are
starting to understand the graphics and
understand just Java in general if you
guys are new to that as well
I mean this probably isn't prettiest way
to code but it's gonna it's gonna work
for us so that's fine
and then the next tutorial will actually
use those points to kind of animate
something maybe I don't know but see it
we get our starting point we first click
we're still press down on the screen and
then when we release up there's our
other plus which is also right in the
center so hopefully you guys liked that
tutorial it's pretty simple pretty quick
and you guys learn about motion events I
got a go peace