All language subtitles for 004 The Four Step Design Process_en

At the end of the last section, we started up our sample application inside of our emulator.

So now you should see the default counter application that tells you how many times you've pressed some

given button and you can click on the button and see that count increment.

Now, I've taken the liberty of also starting up my code editor inside that PIC's directory as well.

And so I encourage you to pause video right now and make sure you start up your code editor to.

Once you get your code editor open, you're going to find a collection of different files and folders

inside of our Picks directory.

We're going to start to explore some of these different files and folders over time.

But right now, we're going to be 100 percent focused on exactly one very specific folder, and that

is the Lib directory.

So 99 percent of all the code that you and I write to build flutter applications is going to be placed

inside of this lib directory.

Every lib directory that you're going to work with is always going to have a main dirt file inside of

it.

The main thought dirt file is very special.

It's the first file that gets loaded up and executed when our application is ran inside of our mobile

device.

So we need to make sure that we always have one file called Main Dart inside the Lib directory.

Now, we can certainly have other files inside of here as well, but at a minimum, we have to have

a main file.

If you now open up this file, you'll see that there's a tremendous amount of code already inside of

here.

Now, I don't know about you, but I like to learn things from scratch.

And I don't really like using a lot of pre generated code.

So rather than trying to work with all this stuff, I'm going to highlight all that code and delete

it like so.

So we'll start completely fresh and we'll get a really good idea of how to build up an application from

scratch.

Now, I'm sure you're very excited to get started on this application right here, but there's going

to be a little bit of a learning curve to get to this point.

So rather than trying to just be line fetching some images and showing them on the screen, I think

we should set a little bit more realistic short term goal.

Let's say that for right now, we'll just try to get some very plain content to appear on the screen

of our device.

So on the screen of our emulator over here, in other words, let's just try to get some very plain

text to show up.

So in order to get some text to show up, I'm going to go back over to my main dirt file and then inside

of here I'm going to lay out a couple of comments that are going to guide me through the process of

getting some content to appear on the screen.

So I'm going to lay out four separate comments that are going to walk us through exactly what we have

to do.

At the very top, I'm going to add a comment that says that I need to import a helper library from Flutter.

To get content on these screen, so can you step one, we're going to have to import some code into

our project and we'll talk exactly about what an import statement is doing for us in just a moment.

But first, let's continue on with a couple more comments, so I think it's second thing we need to

do is define a main function to run when our app starts.

So just as before, back inside of Dark Pad, where we said we have to define a main function, which

is the first function that gets ran inside of our program.

Same is true as a flutter as well.

So every flutter after we build is always going to have exactly one main function defined inside of

it, and that main function will be executed for us automatically.

Then inside that main function, we're going to do two additional steps.

First, we're going to create a new text widget to show some text on the screen.

And then finally, we're going to take that widget and get it on the screen, so creating the text widget

or creating something that's going to show some information on the screen is a slightly different process

than actually taking that thing and telling our mobile device to put it on the screen.

Two separate things.

On the one hand, we have to first create the widget and then the second step is to actually get it

on the screen of our device.

OK, so that's the four steps that we're going to go through.

So let's take a pause right here.

We'll come back to the next section and we're going to start on these four steps.