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We just finished looking over the app, and

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now we're tasked with adding in
a middleman between us and our data.

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This middleman of course
is the content provider.

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So let's start by creating a new class.

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And let's it call MyContentProvider.

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Then let's make it extend
ContentProvider And

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use Alt+Enter to implement
the six required methods.

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Then let's use Alt+Enter a bunch
more to get rid of these warnings.

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All right.

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Now that we've got our content provider,

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we need to turn it into a middleman
between us and our database.

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Let's start by declaring a field for
the context.

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Private Context, and
we'll call it context.

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And then let's create another field for
our database.

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private SQLiteDatabase, and
we'll call it database.

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Then, inside the onCreate function,
let's add a line at the top,

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and set our context field
equal to getContext.

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Then, let's create a new database
helper object, DatabaseHelper,

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and we'll call it databaseHelper
= new DatabaseHelper.

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And we need to parse in our context.

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Next, let's populate our
database field by typing

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database =
databaseHelper.getWritableDatabase.

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And finally, instead of returning false,
we should really be returning whether or

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not the provider was started successfully.

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So let's return database not equal null,

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to return true if the database exists,
and false if it doesn't.

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Awesome.

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That's one function down, and five to go.

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And actually, our app doesn't have
the ability to delete or update data.

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So it's more like three to go.

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But before we move on to the query
function, let's quickly talk about URIs.

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URI, which stands for
Uniform Resource Identifier,

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is pretty much just the address
of a resource in Android.

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Just like how we use
URLs to access web pages,

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we view URIs to access Android resources,
like content providers.

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So each content provider has its own
URI that we can use to access it.

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Getting back to the query function,

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this function takes in
the parameters of a SQL query, and

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should return a cursor containing the
results of that query, though currently,

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we've had no idea what any of these
parameters mean, and it returns null.

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So let's start by renaming these
parameters to make more sense.

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Let's name the second one columns,

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The third one selection,

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the next one selectionArgs,

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and then finally sortOrder.

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And now, hopefully it's a little
easier to see what's going on here.

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It's basically just
a standard SQL statement.

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We select the columns from the URI, and

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then the where clause is just the
selection combined with the selectionArgs,

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by replacing any question marks in
the selection with the next argument.

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Lastly, we can set the order by clause
by using the sortOrder parameter.

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Moving on to the inside of the function,

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we just need to return a cursor
containing the results of this query.

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Let's start by creating a new SQL Lite
Query Builder Object, named builder.

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SQLLiteQueryBuilder, and
we'll call it builder, and

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set it equal to new SQLiteQueryBuilder.

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Then we need to set which
table we're going to query

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by calling the set table's method on our
builder and parsing in our VICS table.

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So builder.setTables and parsing in our
VICS table, DatabaseHelper.TABLE VICS.

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And finally,

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we just need to return the result of
calling the query method on our builder.

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So return builder.query,
which takes in a few parameters.

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For the first parameter,
let's parse in our database,

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which is just database, and
then the second parameter is projection N,

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which is just another way of referring
to the columns we're selecting.

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So let's just parse in columns, and

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then let's parse in selection and
selectionArgs.

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And now, if we like, we can add
a group by or having clause too.

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But we won't be needing either of those,
so let's just parse in null and

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null, and then let's finish up
by parsing in our sortOrder.

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Nice, next step is the getType function.

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This function returns the media type
of the content in the specified URI.

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This way, other applications
can call our getType method

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to see what kind of
content we are providing.

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So if all our data
happened to be HTML code,

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we might return something like text/html,
or

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if it was all PNGs, maybe image/png.

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And if we want,
we can even make up our own media types.

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If you'd like to read
more about media types,

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check out the teacher's notes below.

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Also, if you don't need to tell other
applications what kind of content you're

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providing, then you don't
really need to return anything.

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So I'll just change this
back to return null, And

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then the next video,
we'll start in on the insert function.