Android Application Development Tutorial - 9 - Set up a Button with OnClickListener Video Lecture | Android Application Development (Mobile App) - Software Development

what's going on everybody welcome to
your ninth Android tutorial for the new
Boston what we're gonna do in this
tutorials set up our buttons and
basically use a method that's gonna make
the buttons do something when we click
click the button so we're going to just
set that up we aren't actually going to
define what the button does when it
clicks but if you guys are brand new to
programming this again will be probably
pretty confusing for the most part but
I'm gonna try and break it down a little
bit and then we'll review it later on
down the road but I just want to show
you guys how to set this up now what
we've done we set up two variables
called add and subtract they're both the
type button so they're button variables
and then we set up a reference to the
XML again by the find view by ID method
now also within this on create method so
it will be the second bracket up within
there this is where we're going to set
up our onclicklistener
so basically a button needs to set up an
onclicklistener
and within the parameter or basically
what that's looking for is a on click
listener and the on click listener is
going to use the method on click I was
kind of confusing but I just want to
kind of talk about it or tell you guys
what it does or what it's looking for
for the most part before we get into it
so again like I said since we imported
the button class from the package of the
2.2 Android platform we can use some of
the methods from the button class so how
we use a method is we use our variable
name such as add which again is a button
we hit period or dot and then we have
all these methods we can you choose from
there's one called set on click listener
so this is where we're going to set our
on click listener as you can see it
takes in an on click listener within its
parameters so we're going to set that up
now we don't have an on click listener
yet so we're going to set up a new one
and you do that by saying new and it
comes from the view class so we're going
to say new view dot on click listener
and again Eclipse helps you out so it's
going to be this first choice viewed on
click listener and it's Method so that's
why there's there's a parentheses right
there we're going to click that and we
you click that it's going to set up the
on click method as well so that's what's
really nice about Eclipse and it sets up
this on click listen or on click method
so when our buttons clicked it's going
to do what's ever within these brackets
right here now before we get in to
anything else I want you guys to use a
semicolon and finish off that statement
right there because again just think of
this as one line of code for the most
part this this whole line is basically
one line of code and so you got to
finish it off with a semicolon now that
probably looks really confusing to
brand-new programmers and you're like
what is all this junk trust me guys the
more you use buttons the more this will
become familiar I just want you guys get
a layout like this so you get kind of
familiar with that basically again a
button needs a an onclicklistener
so we have to set the onclick listener
so we set it by using the method set
unclick listener and that takes an
onclick listener within its parameters
I'm saying that a lot so it's probably
confusing you guys but since we don't
have one we had to set up a new one
right here and we kind of defined it by
or there's an on click method that we
can use and again this is where we're
going to actually make your button do
something so there we go we set up our
button onclick listener for a button add
so we're just going to copy that and
paste it down below and change the add
to our other button that we set up sub
so they both have an onclicklistener set
up and you can hit ctrl or command shift
F depending if you're on Mac or Windows
and it kind of formats it for you so you
guys go I mean that's all this tutorial
is I know it's probably not of much help
because especially for you guys you new
guys because it looks so complicated and
it really does for the most part if you
guys are new but you guys will get
familiar with this especially as we go
on throughout the series I'll kind of
explain give you guys some more detail I
just don't want to throw and throw on
all the information at once
but there you go that's basically all
this tutorial is again thanks for
watching guys and I hope to see you guys
in the next tutorial well actually we're
we're actually going to make these
buttons do something so I'll catch you
guys then have a good one