Coroutine

同步代码

import kotlinx.coroutines.*

fun main() {
    runBlocking {
        println("Weather forecast")
        delay(1000)
        println("Sunny")
    }
}

挂起函数

import kotlinx.coroutines.*

fun main() {
    runBlocking {
        println("Weather forecast")
        printForecast()
        printTemperature()
    }
}

suspend fun printForecast() {
    delay(1000)
    println("Sunny")
}

suspend fun printTemperature() {
    delay(1000)
    println("30\u00b0C")
}

输出

Weather forecast
Sunny
30°C

异步代码 launch

import kotlinx.coroutines.*

fun main() {
    runBlocking {
        println("Weather forecast")
        launch {
            printForecast()
        }
        launch {
            printTemperature()
        }
    }
}

suspend fun printForecast() {
    delay(1000)
    println("Sunny")
}

suspend fun printTemperature() {
    delay(1000)
    println("30\u00b0C")
}

带有返回值的异步代码 async

import kotlinx.coroutines.*

fun main() {
    runBlocking {
        println("Weather forecast")
        val forecast: Deferred<String> = async {
            getForecast()
        }
        val temperature: Deferred<String> = async {
            getTemperature()
        }
        println("${forecast.await()} ${temperature.await()}")
        println("Have a good day!")
    }
}

suspend fun getForecast(): String {
    delay(1000)
    return "Sunny"
}

suspend fun getTemperature(): String {
    delay(1000)
    return "30\u00b0C"
}