Now that we've got our application up and running on our mobile device let's open up our code editor
and start exploring our project directory just to see what we're working with here.
It's going to start up my code editor just you know there's not necessarily one code editor that is
better for working with React Native than another you can use any editor that you want to use.
It's going to open up that project directory we just created of our starter and then right away inside
of here we're gonna see a couple of different files and folders.
Now as I mentioned I generate this project ahead of time and added in just a little bit of code to it.
We are going to eventually generate projects together.
We'll walk through that entire process.
But for right now we're just gonna use the starter project inside of here.
You'll notice a file called Ask me a folder called s RC and then inside there is a screen directory
and then inside there is a file called home screen.
If you open up that file right now you're going to see some little bit of something it looks like h
t mail right there and inside of it is the word home screen.
So I'm going to assume that at this point in time you've got your application up and running on your
physical device.
Hopefully you see those words home screen on your physical device.
If you do I want you to try changing the text inside of there to something else something like maybe
I don't know Hi there or something similar.
I'm then going to go ahead and save that.
Emily after now we should see a change automatically appear on your mobile device.
You'll notice right here I'm running a simulator for iPhone and emulator for Android just so you can
see very easily what I get.
But if you are running your own physical device you should see that change up here right away.
If you don't see that change up you're right away.
You can always close down the expo app and re scan that QR code.
One thing I want you to notice here is that we get library load.
Anytime that we make use or make a change to our ReACT native project.
So in other words anytime we change something inside of a javascript file the application should automatically
reload for us.
There's one other thing that I want you to see very quickly once again inside of my home screen that
J.S. file.
I'm going to go down to the very bottom down here and I'm going to add in a couple of just like whatever
characters like so something that's going to definitely cause an error so that a doubt that is not valid
javascript code after putting that in there I'm going to save that.
And then on your mobile device you should see a big red error message like the one right here.
This is going to be the air screen that you see very frequently.
Anytime you make a typo or some kind of exception HAMP happens inside your application at the very top.
Inside this red box right here is a description of the error that just occurred.
You'll notice that inside this path right here we're told the exact file and line that the error occurred
on.
So in this case we're being told that inside the home screen J.S. file on line 17.
There is some air.
So if we want to fix this.
Well very simply we would go back over delete those extra characters save the file and then we should
see the error message go away.
Now unfortunately if you're running an iPhone you might not see the error message go away automatically.
You'll notice that on my android emulator the error message did go away.
But on the iPhone it's still here.
So if you still see that error message on an iPhone after you have fixed an error or at least you think
you fixed it then there are a couple of steps we can go through to manually clear this error message.
First off you'll notice that there are a couple buttons down here at the bottom of the screen that you
can tap.
So you could hit reload once you hit reload you're almost always going to see a second error message
one that looks like attempting to reload bridge.
You can hit reload again and then hopefully the application should reload and you'll then see your content
appear on the screen again.
OK.
So what we've learned here is that whenever we make a change to our project our application should automatically
reload and if we ever cause an error we're going to see that big red error message that tells us exactly
what went wrong.
And if you're running an iPhone you might have to manually clear out that error message.
Sometimes it's not going to go away automatically.
OK.
So now we've gone through some very simple things inside of our code.
Ed let's come back the next video we're going to start to discuss.
Well what react and react native are all about a quick pause and I'll see you in just a minute.