- Simple Refactoring: Creating a New Class 5:45
- Creating a New Class 2 objectives
- Simple Refactoring: Using a New Class 3:47
- Simple Refactoring 5 questions
- Dynamically Changing the Background Color 3:58
- Dynamically Changing the Background Color 1 objective
- Adding More Colors 3:52
- Using the New Colors 3:38
- Adding Colors 1 objective
- Adding an App Icon 4:47
- Adding an App Icon 3 questions
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Adding More Colors
3:52Let's continue with adding additional colors as the background for each new fun fact. We'll add a new Java object to hold the colors and serve one up on each tap of the button!
It's finally time to
add colors to our app.
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Let's create a new class called
ColorWheel, that stores our colors and
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picks new ones for us.
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It'll be very similar
to our FactBook class.
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In the project name,
let's right-click on the package name and
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select New > Kotlin File/Class.
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Let's name it ColorWheel.
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Make it a class instead of a file,
and hit Enter.
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Now we're going to copy and
past our code from our FactBook class and
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make a few key changes.
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Let's switch over to our FactBook class.
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Then let's select
everything after the word,
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FactBook then use Cmd,
or Ctrl+C to copy it.
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Then let's go back to
the ColorWheel class,
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select everything after
the word ColorWheel.
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Then use Cmd, or
Ctrl+V to paste it back in.
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Android Studio then notices
that we're missing an import.
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We didn't copy the import
statement form our FactBook class,
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which means it didn't get pasted here.
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Hit OK to generate the import,
and now we're good to go.
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Instead of facts,
we'd like these to be colors.
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Let's start by refactoring
facts to be named colors.
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Right click on facts,
select Refactor > Rename.
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Note that the keyboard
shortcut is Shift+F6, and
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then type colors and hit Enter.
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Now I'm going to copy and paste in some
colors in the form of hexadecimal strings.
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Remember, the colors we want to use are
the Treehouse topic colors from the web.
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Here's the color sheet
we looked at before.
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There's a link in
the teacher's notes below.
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If you want, you can come to this page and
individually grab each code and
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create the array.
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But I'll copy and paste in the array
from the teachers notes to save time.
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Okay, let's copy the array and
then back in Android Studio,
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I'm going to put this last closing
parenthesis on a new line.
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And then paste our colors
array over our facts array.
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Now, that we've got all our colors, let's
make a few changes to the getFact method.
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First off, we probably shouldn't
call it getFact anymore.
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Let's change it to getColor.
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Since this method is never used,
that's what this gray text is telling us,
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we don't need to bother with refactoring.
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We can just rename it
the old-fashioned way.
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Great!
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Now the cool thing is we don't need to
change anything about our randomNumber
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generator.
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We still use the random class and
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still pick a random number based on
the length of the array up here.
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Though we should change the comment
to say Randomly select a color.
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Now let's get back to FunFactsActivity.
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And the first thing we need to do is
create a new ColorWheel object as
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a property,
just like we did with FaceBook.
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Let's add a new line at the top below our
FactBook and create a new private vowel
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named colorWheel.
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And set it equal to a new ColorWheel.
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Now down in our on click listener,
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we can pick a new color just
like we did for the fact.
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Let's add a couple lines
after we set our fact and
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then type val color =
colorWheel.getColor().
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Then let's use our new color
variable as a parameter to
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this setBackgroundColor method.
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Which gives us an error.
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If we hover over it, we'll see
the we're getting a type mismatch.
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The method expects an int,
but we're giving it a string.
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So how are we gonna make this work?
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Well, don't worry,
as usual there is this simple solution.
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We need to convert data like
this a lot in programming.
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Remember programming is primarily about
working with and manipulating data.
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Let's take a short break, and then in
the next video, we'll fix this error.
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