Android Application Development Tutorial - 73 - Graphics Trick Video Lecture | Android Application Development (Mobile App) - Software Development

what's up guys welcome your 7030 Android
tutorial we're gonna get rid of some of
these errors I mean they're really
errors but when we click we want it to
pan in the center of this ball instead
of you know top left corner well at
least make it seem like it's being
painted in the center right while
retouch the other one is we want to be
able to drag this object around and
follow our cursor when we're touching
the screen still so let's get rid of our
first bitmap problem and what we're
doing now is we're just basically
getting the location and then we're
painting the top-left corner at that
location what we want to do instead is
for example if I click right in the
center of the screen it paints our
bitmap a little lower and a little more
to the right so what we're gonna do
right here is our X and our Y we're
gonna take our X minus half of our
bitmap width and then that's going to
give us right here ill paint and then
we're gonna do the Y minus half of the
height so we're gonna paint here so
basically here's our X&Y and then we're
gonna subtract half of our width of our
bitmap so here and half of our height
and then we're gonna go here this is the
point that's gonna give us and then
we're going to draw our bitmap again
it's still gonna be the top-left corner
but it's gonna draw it up here and then
you know our circle is gonna be right
there I don't know if that's kind of
confusing or not but let's just do it so
we're gonna say - and then we take our
bitmap so we're gonna say - bitmap which
we called test and then we say dot get
width for the X the x value so we're
gonna say get width this is just kind of
a common trick that programmers used for
the most part boat so think of it just
you know kind of how I explained it's
giving us half of the width of the
length of our bitmap and then we're
going to subtract that from the from the
x value we're also going to do that for
the Y value as well so we're gonna say -
test dot get height this time / - I
don't know if that's confusing or not
but I just want to show you guys that
because it's pretty common and in
programming especially for game
programming and bit
Maps and now when we run our or let's
just finish it because the other
problems pretty simple as well so this
touch on touch method basically it's
returning false so once it gives us our
our information it's just me like falls
from done no more need to check these
variables and and we don't want it to do
that we want it to kind of loop through
so instead of saying false we're gonna
say true and that's just gonna kind of
allow it to keep giving us those numbers
for the most part so that's the simple
fix for making the bitmap actually
follow our cursor when we're clicked
down pretty simple I mean it's not much
of a tutorial I know but hopefully you
learn something a little bit about the
return value for the on touch and as
well as kind of that graphics trick so
when we click now the bitmap appears
right in the center for the most part
yeah right where we click it seems like
it's appearing right there and then the
other thing we need to do is click and
drag and as you can see now since we
change that return from false to true
our bitmap is kind of following us along
and in the next tutorial not quite sure
what we're gonna do yet I might do a
little maybe like one or two more on
this graphic stuff and then we're gonna
get into something completely different
so I'll catch you guys in peace