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In this video, we'll be refactoring
our code one last time.

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That's not to say that what
we've got right now is bad.

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But I'd just like to show you
another way we can refactor this.

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Here's the code we started with.

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We had one ingredients fragment class and
one directions fragment class.

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They were totally separate and
we were repeating a lot of code.

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Then, in the last video, we refactored
this to instead use only one class,

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CheckBoxesFragment.

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And in order to determine
whether to show ingredients or

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directions, we pass in a Boolean, and

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then use that Boolean to grab
the correct data from the recipes class.

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Now, instead of passing in a Boolean,
let's recreate our ingredients and

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directions fragments, but this time let's
make them extend CheckBoxesFragment.

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This way, we won't need to repeat
any code in our ingredients and

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directions fragments.

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The only code they'll have is
the code that makes them different.

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Let's start by getting rid
of the KEY-IS_INGREDIENTS

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field in our view pager fragment class.

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And delete these two lines
that show errors now, as well.

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Then, over in CheckBoxesFragment,
let's delete the isIngredients variable.

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And also,
the if statement that relies on it.

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Which leaves us with a contents
array that never gets initialized,

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so let's set it equal to getContents and
pass in our index.

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Then let's use alt+Enter
to create this method.

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Now, when we extend this class, we just
need to override the get contents method.

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And provide our own implementation
returning whatever string array

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we'd like to display.

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But we can't extend private methods,
so let's change this to public.

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And before moving on,
let's think about this a little more.

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Specifically, would we ever want to create
an instance of check boxes fragment?

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Probably not, it would just be
an empty screen with no check boxes.

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This Default implementation of
getContents is pretty useless,

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we're always going to
override this method.

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And what do we call a class
that can never be instantiated?

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Abstract, a little louder please,
abstract.

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That's right,
abstract classes cannot be instantiated.

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And since we never want this class to
be instantiated, we should probably

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declare it as abstract by adding the
abstract keyword between public and class.

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In addition, we also want to require
that any class extending this one

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overrides the getContents method.

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If they don't override it,
we won't know what to display.

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We can do this by also declaring
the getContents method as abstract.

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Let's add the abstract key
word after the word public.

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And then, since we don't want to
provide an implementation here,

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let's get rid of the method body,
And then add a semi colon.

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All right, now let's see it in action by
creating a new IngredientsFragment class.

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And let's make it extend
to CheckBoxesFragment.

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And if we read the error, it looks
like this class either needs to be

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declared abstract or we need to
implement our getContents method.

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Let's use alt+Enter,
to implement the method.

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And now we just need to return the array
of ingredients, just like we did earlier.

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return
Recipes.ingredients[index].split("`"),

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cool, now let's do the same steps for

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our directions fragment.

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Create it.

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Make it extend CheckBoxesFragment,

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use Alt+Enter to implement getContents.

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And then return the directions for
the selected recipe, Recipes.directions

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[index].split("`").

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Finally, back in ViewPagerFragment, let's
switch back to using the ingredients and

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directions fragments, instead of
using two check boxes fragments.

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Then let's test the app and
make sure it still works just the same.

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Nice, we've just seen two different
ways to refactor the same code.

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First, we passed in an argument
to a check boxes fragment.

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And second, we brought back the separate
ingredients and directions fragments but

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changed them to extend
a common base class.

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But which of these is
the better refactoring?

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Well, for the most part,
it doesn't matter.

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They both work and they both keep
us from repeating ourselves.

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That said, we'll be sticking
with the second refactoring,

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it does a better job at
separating our concerns.

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If we want to make a change to
only the directions fragment,

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it'll be easier with
the second refactoring.

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Coming up, we'll see what it takes
to make our app ready for tablets.