[JAVA] How to study kotlin for the first time ~ Part 2 ~

Previous article First-time kotlin study method-Part 1-

(Note: I wrote it last time, but I wrote a little more reference time)

Then, we're finally going into Kotlin

I took a look at the Kotlin reference for revenge

Time required: 1 minute

I understand a little, but I don't understand at all w

I returned to my teacher. (Dot Install)

Time required 16 hours Take the following with dot installation --Introduction to Kotlin --Introduction to Android application development (11 times in total)

Actually, the syntax is different at this point, so it will end soon. ~ Except for the memo app of Part 1 ~, it is designed to be smooth.

A little detour

Time required 80 hours [Kotlin Start Book](https://www.amazon.co.jp/Kotlin%E3%82%B9%E3%82%BF%E3%83%BC%E3%83%88%E3%83%96% E3% 83% 83% E3% 82% AF-% E6% 96% B0% E3% 81% 97% E3% 81% 84Android% E3% 83% 97% E3% 83% AD% E3% 82% B0% E3 % 83% A9% E3% 83% 9F% E3% 83% B3% E3% 82% B0-% E9% 95% B7% E6% BE% A4-% E5% A4% AA% E9% 83% 8E / dp /4865940391/ref=sr_1_1?adgrpid=52564297599&hvadid=259132820568&hvdev=c&hvlocphy=1009332&hvnetw=g&hvpos=1t1&hvqmt=e&hvrand=13219668387082692110&hvtargid=kwd-315885033021&hvtargid=kwd-315885033021&hvtargid=kwd-315885033021&jp- I read% 83% BC% E3% 83% 88% E3% 83% 96% E3% 83% 83% E3% 82% AF & qid = 15562615427 & s = gateway & sr = 8-1 & tag = googhydr-22)

Is it a book that is regarded as a gateway to the dragon in the neighborhood? Notations that are difficult for beginners here (lambda expressions, recursive calls, closures, etc.) I learned a lot because there was an introduction to the library (Retrofit, RxAndroid, Dagger2).

I've never done Java, and the library itself is being updated. It took a while.

Once again open source

I referred to google.

googlesamples/android-architecture googlesamples/android-architecture-components

Here you can get a feel for the latest trends. In addition, please google appropriately and look for popular libraries. If you get up to this point, you will be able to understand it.

Practice 2

Let's take a look at the source I made in Part 1. Hold your belly and laugh. If this could be refactored, it would be a great Kotlin player.

Impressions

I have somehow grasped how to write test code. After that, if you have time to write code, you can do anything. You should also have the ability to look up.

I will omit the method of uploading to google play here. Please note. Thank you for reading this far!