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[MUSIC]

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Welcome back.

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We've set up our user interface,
the view portion of the MVC pattern.

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The model portion,

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our Hour class, will need a little more
work down the road, but nothing too major.

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I wan to turn our attention, at least for

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a little bit here, to the controller
portion of the MVC design pattern.

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I've mentioned adapter and
view holders a couple of times now.

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But what are they exactly?

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And how do they all fit together?

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When we use a RecyclerView,
there are a few bits and pieces we need.

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We have data, our array of hourly info for
this project.

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And we have a RecyclerView.

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What we need to do to display
the data in the RecyclerView?

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A common design pattern in Android
is to use a special component

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called an adapter to, well,
adapt data for the view.

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We set the data for the adapter and

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let the adapter do its magic to make the
data look nice inside the RecyclerView.

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The other pieces to the puzzle
are a LayoutManager,

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which manages the positioning
of the items.

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And a ViewHolder,
which as the name would indicate,

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holds the views we added
to our list item layout.

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Our task then are to, first,

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create an Adapter to handle the data
collection and bind it to the View.

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Create a ViewHolder inside the Adapter.

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Connect the Adapter to the Activity.

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And assign a LayoutManager
to manage the item position.

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Something to note here.

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Since we're using the Android Data Binding
Library, many of the data binding tasks

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that move data around the list and
RecyclerView are handled for us.

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There are other ways outside the Data
Binding Library to accomplish these tasks.

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And I've put links in the teacher's notes
for further reading in case you come

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across a different method
in your development career.