Android developers love Kotlin interface After using Kotlin in Android development for a while, I’ve just realized the benefit of Interface in Kotlin.In Java 6, Interface can only be used to describe the behaviors, but not implement them.

控制流：if、when、for、while. If 表达式. 在Kotlin 中，if是一个表达式，即它会返回一个值。因此就不需要三元运算符（条件? 然后: 否则），因为普通的if 就能胜任

The argument of when expression compares with all the branches one by one until some match is found. Kotlin gives us a powerful conditional called when, which enables us to basically write that same table in our code. Here’s how it looks. val temperature = 48 val reaction = when { temperature > 55 -> "It's too hot!" temperature < 40 -> "It's too cold!" Se hela listan på tutorialsandyou.com Kotlin (/ ˈ k ɒ t l ɪ n /) is a cross-platform, statically typed, general-purpose programming language with type inference.Kotlin is designed to interoperate fully with Java, and the JVM version of Kotlin's standard library depends on the Java Class Library, but type inference allows its syntax to be more concise. when 式の基本.

Kotlin when

It can be used either as a statement or as an expression. Android developers love Kotlin interface After using Kotlin in Android development for a while, I’ve just realized the benefit of Interface in Kotlin.In Java 6, Interface can only be used to describe the behaviors, but not implement them. Kotlin supports “delegation” design pattern by introducing a new keyword “by”. Using this keyword or delegation methodology, Kotlin allows the derived class to access all the implemented public methods of an interface through a specific object.

Kotlin when expression is used when we have to choose a particular statement based on different values of a variable. It is similar to switch case in other

when 式の基本. Kotlin の when 式は、Java の switch 文に相当するものです。. Java の switch は、列挙型、文字列、数値しか扱えませんが、Kotlin の when では任意のオブジェクトで分岐を行うことができます。. ポイントは式 (expression) であるというところで、条件分岐後の評価結果をそのまま変数に代入したり、関数の戻り値として使うことができます。.

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This is a keyword that tells Kotlin that you want to do something different depending on the circumstances. Note that when is an expression, so it is evaluated and can be assigned to a variable. In this case, it will evaluate to a string, which will be assigned to the reaction variable.

= null // Nullable type println(name.length()) // Compilation error // And if you check a type is right, the compiler will auto-cast it for you fun calculateTotal(obj: Any) { if (obj is Invoice) … A few main points about Kotlin when: In Kotlin, the when can be used as an expression or statement. If using ‘when’ as an expression then the satisfied branch’s value becomes the value of the overall expression. In the case of using it as a statement, the values of the individual branches are ignored. A when expression is a replacement of a switch statement known from C family of languages. Kotlin is a statically-typed programming language that runs on the Java virtual machine. Kotlin when matches its argument against all branches sequentially until some branch condition is satisfied.
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Note that when is an expression, so it is evaluated and can be assigned to a variable. In this case, it will evaluate to a string, which will be assigned to the reaction variable. Kotlin has great support and many contributors in its fast-growing global community.

First, there’s when.
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Kotlin, and some react native (really little) anders.froberg@liu.se Recap. • Rita komponenter själv (kod). • Testing mostly code. • Kotlin. • React native (start up)

It is similar to switch case in other Kotlin when expression is used when you have to match the value of an expression to a set of values and execute a block of statement corresponding to the when operator matches its argument with all the branches until it matches with anyone, else it executes the else block. It can be used as an expression where In Kotlin, we have no switch statement. Instead, Kotlin replaces the switch with the When expression. Sep 19, 2019 Back in 2015 when I only started trying Kotlin (many thanks to Jake Wharton for his thorough investigation) and then later, when Kotlin 1.0 was Kotlin static code analysis. Unique rules to find Bugs, Security Hotspots, and Code Smells in your KOTLIN code. All rules 43 · Bug7 · Security Hotspot2 · Code Example#. Like if, when can also be used as an expression: val greeting = when (x) { "English" -> "How are you?" "German This document serves as the complete definition of Google's Android coding standards for source code in the Kotlin Programming Language.