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Everything is good here except
the last page of our story.

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If we try to go all the way to one
of those right now then we'll get

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an exception because we don't have
any data in our choice objects.

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Ugh, unhandled exceptions are the worst.

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Let's fix it.

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Hopefully you were able to take a look
at the log and see what the error was.

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Let's go back to Android Studio and

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bring up the logcat view with
the Android Monitor tab down here.

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And we can see pretty quickly here at
the bottom that we're running into a null

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pointer exception.

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If we keep reading,
we can find out that it's happening

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when we try to call getTextID
on a null object here.

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So basically what is happening is
when we get to one of our pages that

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doesn't have any choice objects,
we're getting this null pointer exception.

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Remember, the last page of the story
we decided won't have any choices.

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And instead have a boolean flag that
says if it's the final page or not.

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Okay, let's fix it.

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Just for quick review,
let's take a look at the page class.

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So let's close this, open up Page.

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And remember,
we added this isFinalPage flag and

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some methods that tells us
if it's a final page or not.

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And right now, if we scroll down here,
it says that it is not being used.

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So let's use it.

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Let's go back to StoryActivity.

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So back here in our loadPage method is
where we are setting all the information

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related to the choice buttons.

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So here, before line 61,
let's add a new line, and

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a check if (page.isFinalPage()).

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And then inside here,
if it's the final page,

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we want to execute some code to handle
the buttons a little bit differently.

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If it's not final then we still want
to do the rest of all this work.

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So let's make that the else block.

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We'll add else, curly brace,
scroll down a little bit and

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I'll put another curly brace down here.

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And everything is indented automatically,
thank you Android Studio.

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Actually, this loadPage method is
getting a little bit long for my taste.

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It's doing too much work at this point.

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Let's refactor this else block into
a new method just to load the buttons.

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So I'm going to select everything in here,
click on refactor,

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extract, method.

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And let's call this loadButtons and
click OK.

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All right, so
coming back to our if statement,

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how exactly should we handle this
situation of the final pages?

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Well, let's take a look
at the mock ups again.

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Our designer and
I talked about this specific scenario.

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And you can see here
on the last two pages,

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we decided to have one button
that just says, Play Again.

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Tapping on that will take the user
back to the initial screen.

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So, to accomplish this, we are going
to have to hide the top button, and

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then change the text on the bottom button,
and change its target.

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Hiding the button is really easy.

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There are two different ways we can do it.

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The choice one button is the top button.

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So let's do choice1Button.,
and then we'll use

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a method called setVisibility,
and you can guess what it does.

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It sets things to visible or invisible.

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Now the parameter isn't in parameter, but

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there are a couple different constants
in the view class that we can use.

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So start typing view with a capital V,
dot, and

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we have VISIBLE and
INVISIBLE right here at the top.

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These two should be pretty
obvious about what they do.

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They make the view either visible or
invisible.

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There's another one, View.gone,

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that removes the view
completely from it's parent.

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Which can effect how things
are laid out on the screen.

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Especially if other views are positioned
relative to the view that we call this on.

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So we wanna make sure
we use the right one.

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We just wanna make this INVISIBLE.

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Next we want to set the text of the other
button, the one that is still visible.

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So we can go choice2Button.setText and

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the text in this case
is simply "PLAY AGAIN".

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And check this out.

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We can refactor from code directly
into a string resource too.

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So it's highlighted in yellow for
us, we can hit Alt + Enter,

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go down here to extract string resource,
and for the resource name let's call this.

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Play_again_button_text.

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And there we go, it gets popped in
here instead of the hard coded string.

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Okay, let's run this and see how it works.

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All right,
let's keep testing different names.

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We'll have Brittney start
the story this time, and

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let's go through to one of the end points.

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Explore the coordinates, and
there we go, PLAY AGAIN.

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And if we tap on the button it takes us to
another page, that's because the on click

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listener for the button was still
pointing to the old target.

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Now if I tap on it here
nothing will happen.

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All right, so
we have two final things to take care of.

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We need to make this PLAY AGAIN
button work correctly and

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take us back to the start, and
we need to fix our back navigation.

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Check this out.
If we hit the back button,

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instead of going back
through the pages of a story,

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it's going to take us
back to the beginning.

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That's not what we want.

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Let's break for a moment.

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And then when we come back, we will
tackle the PLAY AGAIN button first.