Name: Kotlin介紹（Google I/O'17 (Introduction to Kotlin (Google I/O '17))
Uploaded: 2021-01-14T06:54:55.000Z
Duration: 38 min 39 s
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So I'm Romain Guy, representing the Platform team on Android,

and this is Tor Norbye representing the Tools team.

have been incredibly excited about this official

We both love Kotlin, in case you hadn't noticed already.

And we don't take any more time from the speakers of honor.

So I was thinking the other day, the first time that I ever

did a talk on Kotlin, it was like 4 and 1/2 years ago.

And they gave me a room for 900 people and 7 people showed up.

So it's kind of nice to see more of you show up today.

Anyway I've got roughly around 30 minutes.

28 minutes to give you a whirlwind tour of Kotlin,

so I'm not going to cover the entire language.

I'm going to try show you as much as I possibly can

and how you can use it and where it provides you

So I'm going to try and do it all with live coding,

so if it all goes terribly wrong, there's a Google video--

I mean there's a YouTube video of this somewhere as well.

OK, so we're going to start with something very simple

So data class, I'm going to create a new type called money,

and it's going to happen amounts which is of type Int.

And it's going to have a currency of type string.

So this is something that you're already familiar with.

Let's go ahead and compare that to a Java one

And let's get the Java money up-- actually,

That's kind of the equivalent of what I've just written, right.

And this data modifier over here, what that's doing

is essentially giving me a whole bunch of things,

like the to string, it's giving me the clone,

which in Kotlin it's called copy, it's doing the equals,

Because any good IDE is going to generate that for me.

But the problem is that that's code you're

you're going to have to go back and change that code.

And the other issue that you're going to have is you

that IDE has generated for you, or you've

So it's not just about saving on typing on the first line.

And this is the top entry point of Kotlin,

so you have a public static void main in a class.

So in Kotlin, you can put everything in the top level.

It's kind of like JavaScript in a good way.

and I want to reiterate, every function and everything

that I'll show you today, I'm going to just add it

but that doesn't mean that you don't have any more member

So I'm going to create a new instance of money.

We're going to call it, for example, tickets.

And I'll say Money 100, and it's going to be dollars, right?

And I'll get into the explicit type here,

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Kotlin介紹（Google I/O'17 (Introduction to Kotlin (Google I/O '17))

essentially

bunch

expression

basically