[JAVA] [Kotlin] Resources and tips for learning a new programming language

This article is written for those who want to learn how to develop Android smartphone applications in the Kotlin language for the first time.

Introduction

When trying to learn a new programming language or development environment, the first important thing is to collect information. It's a good idea to have a good book and read it through. Once you've learned everything, the next step is to put it into practice. It is a good idea to read the samples on the Internet carefully and study with books that are rich in samples. Finally, let's decide the theme by ourselves and complete one application. The same is true for Kotlin. It's important to read the book, understand the sample, and actually complete the app, which is a shortcut for learning.

Tips for learning Kotlin

Let's move our hands. Even if you think you can understand it by reading a book or watching a video, it is difficult to settle as a memory unless you actually move your hand. Let's actually enter and execute the code in Kotlin's REPL environment.

Let's change it a little

Let's change the sample source a little. You can understand where to change and how it behaves.

Let's touch many samples

Let's run a lot of sample sources. Understanding what you can do with Kotlin and Android is the fastest way to make the application you want to build a reality. It's also a source of app ideas for those who haven't decided what kind of application they want to create.

Resources for Kotlin learning

I have collected the things that I used as a reference when learning Kotlin and the things that seemed to be helpful.

Books

There are not many Kotlin language reference books yet. I will list the standard books.

A refreshing introduction to Java

http://amzn.to/2B7i81S The best-selling Java Primer. If you are a complete programming beginner, read through and then enter Kotlin. It gives you a better understanding of object-orientation and Java, so you can get into Kotlin more easily. Kotlin is the Java Vertial Machine language. It's not unrelated to Java. Therefore, some knowledge of Java is required. If you are a complete programming beginner with no object-oriented knowledge or no knowledge of Java, what is Java and what is an object? It would be good to enter from that place. Learning Java to learn Kotlin seems like a detour, and that's the fastest way. Especially if you are developing Android, it is useful to make it readable without Java because the Android API is currently made in Java.

Kotlin Start Book

http://amzn.to/2iKHE6v This is the so-called Akabeko book. This is a book by Taro (Representative of Kotlin User Group in Japan).

Kotlin in action

http://amzn.to/2A4N2LH If you're not satisfied with your Kotlin Startbook, you might want to read this too. Compatible with Kotlin 1.0.

Kotlin for Android Developers(English) https://leanpub.com/kotlin-for-android-developers It is sold at Leanpub, a site where you can sell and buy e-books. If the contents are different from what you expected after purchase, you can return it. There is no detailed explanation, so it is for those who can download the sample code and read it while referring to it, and for those who have some programming experience. Not recommended for beginners.

Android Kotlin Style Guide

https://android.github.io/kotlin-guides/style.html Rules and coding standards for developing Android applications in Kotlin. It's a good idea to follow the naming conventions and formats.

Kotlin cheat sheet

https://qiita.com/emboss369/items/c39f196e703447820b47 If you're mastering Java and want to touch Kotlin for a moment, I think it's faster to actually run Kotlin code. I created a Kotlin cheat sheet with code that I can run there. This is useful for Java programmers who want to take a quick look at Kotlin in 10 minutes, or for programmers who are new to Kotlin and have forgotten how to write Kotlin. You can also execute code from a web browser, which speeds up your understanding.

First Android Programming 3rd Edition

https://amzn.to/2HkGEA5 This is a book written for those who want to start Android with Kotlin. Kotlin & Andrew carefully explains not to stumble for the first time. I think this is the first Kotlin book in the Android introductory book, so please refer to it.

Sample source

In order to be able to write more and more practical code, just imitate the human source. The sample source is a good teaching material. Let's get a deeper understanding of Kotlin and Android while running the sample. Then try changing the sample source yourself and see how it works.

Try Kotlin https://try.kotlinlang.org/ You can find a lot of Kotlin sample code in "Examples". What's more, you can run Kotlin online, so you can try it out. You can also learn Kotlin's language, syntax, structure, and some common functions and libraries in a short amount of time by solving 42 questions in Kotlin Koans.

Kotlin samples https://developer.android.com/samples/index.html?language=kotlin There aren't many Kotlin sample sources yet, but Google's samples are abundant and helpful.

If you have any resources you recommend, please leave them in the comments!

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