Android Application Development Tutorial - 98 - File Output Stream for Internal Storage Video Lecture | Android Application Development (Mobile App) - Software Development

oh hey guys what's up welcome to 98 the
enjoy tutorial for the new Boston and
again what we're going to do in this
tutorial is work with some data like
said for the next few tutorials because
it's pretty it's pretty crucial thing
for most applications you want to save
some file save some data somewhere and
so I'm going to kind of go through
different ways you can do that now what
we've worked with is the shared
preferences which is good for key and
pair values third key I'm sorry key
value pairs for the most part so if you
want to save just the variable have that
variable change and update it we can do
that now another way we can save some
data or save some files and two is again
internal storage which is pretty similar
to shared preferences but I just want to
show you guys some more stuff that we
can do and this data will be saved
internally in the internal storage so
what's going to happen is if they
uninstall our application it is going to
be deleted this internal storage that
we're going to create here or this file
so the first thing that we want to do is
we want to set up our class and don't
worry we'd only create a new XML layout
finally so we're just going to use the
same one that we did from the other
class as well I'm just going to move
this up here get started and as you can
see I implemented the onclicklistener so
it's nothing new there I have a ton of
import so you guys don't need to worry
about so what we're going to do within
our on create method we're going to set
our content view to was it r dot layout
dot
man shared preferences it's gonna be the
same layout same kind of stuff that we
worked with when we did shared
preferences so now what we can also do
is we can open up our shared preferences
class just save some time and we can
copy this set up variables method here
actually just kind of copy everything
from here which is our own clique method
which is just a switching case and are
set up variables method copy that and
we're going to go over to an internal
data and we're going to since we copied
our on click method I'm just going to
delete the one that it's set up for us
and hit paste and we're going to delete
whatever is within our save and our load
button so now that we've copied it we
just need to call this method set up
variables within our on create method so
it kind of initial eyes does all of our
variables there and we also want to add
the references to our edit text in our
text view so we'll do that above our
class
and a textview
called data results and there we go we
pretty much have everything set up for
tutorial now now how we're going to work
with the internal storage is we're going
to create a file output stream to write
our data and then we're going to create
a file input stream to read our data so
let's first just for this tutorial we're
going to write some data but let's first
create our file output stream so again
we want this to be a variable that we
can use throughout our whole class so
we're going to say file output stream
this and we're going to call fos we're
foss foss and within our setup variables
we're also just going to quickly create
it and and then close it for the most
part so we know that it exists and we
also want to have a file name just like
the last tutorial so we're going to set
up a string that's going to be our file
name and we're going to say string file
name equals internal string something
like that so what we need to do is we
need to create this file output stream
within our on create method set it up to
or file name and set up how we want to
write to it and all that good stuff so
we're going to do that within our on
create method again we have this method
called set up variables so we're just
going to set it up within that method
which is going to be called within our
on create we're just going to set it up
and then close it for the most part so
we created this file output stream again
output is how we write data and we're
going to set that equal to something
called or using a method called Open
File output and what it takes within as
parameters is the file name again we
just set up that variable as our string
reference called internal internal
string and we also want to say the way
that we want to write to it for the most
part so context dot mode private so we
don't want anyone to see this file name
we want to only be able to access it
within Co
for the most part so we're going to use
the default you know mode private it's
giving us an error because when we open
data try and write to data load data all
that good stuff it's not always you know
it's one of those sketchy things we have
to surround it with a try and catch
Klaus so we can easily just hover over
the air and say surround with try and
catch Klaus going to click that and now
it's going to catch if a file has not
been found for the most part exception
and then print it to the stack trace
what we also want to do is after we
create this file output stream we just
want to close it so anytime we open it
we need to close it so we're just going
to do that quickly
fos dot close and there we go
and again it's going to say hey we are
trying to close it we need to surround
this with a try and catch as well but
since it's already within the try
bracket what we're going to do is we're
going to say add a catch clause to the
surrounding try and as you can see once
we click that it adds this input output
exception so we have two things within
our try bracket and two exceptions that
it can catch again file not found and
the file exception our input output
exception so again it just prints it to
the stack trace and that's pretty much
it for this tutorial we didn't write
anything we basically just created our
file output stream using the reference
of our file name saying we want to you
know write to it privately and then we
closed it within our on create method so
in the next tutorial we'll show you guys
how to actually write to this stream and
and it's going to be pretty simple for
the most part and I'll catch you then
have a good one