Android 协程上下文的元素。上下文的继承 异常处理

有时候我们需要定义多个元素，我们可以使用+操作符实现

其原因就是因为参数实现了plus方法

如

    @Test
    fun `test CoroutineContext`() {
        runBlocking<Unit> {
            launch(Dispatchers.Default + CoroutineName("test")) {
                println("I'm working in thread ${Thread.currentThread().name}")
            }
        }
    }

上下文的继承

    @Test
    fun `test CoroutineContext extend`() = runBlocking<Unit> {
        val scope = CoroutineScope(Job() + Dispatchers.IO + CoroutineName("test"))
        val job = scope.launch {
            println("${coroutineContext[Job]} ${Thread.currentThread().name}")
            val result = async {
                println("${coroutineContext[Job]} ${Thread.currentThread().name}")
                "Ok"
            }.await()
        }
        job.join()
    }

launch协程里面的上下文就是 scope的上下文

那么async是launcher的子类

 上下文的公式=默认值+继承的CoroutineContext+参数

 协程的异常处理

   @Test
    fun `test CoroutineContext extend2`() = runBlocking<Unit> {
        val coroutineExceptionHandler = CoroutineExceptionHandler { _, throwable ->
            println("Caught $throwable")
        }
        val scope = CoroutineScope(Job() + Dispatchers.Main + coroutineExceptionHandler)
        val job = scope.launch(Dispatchers.IO) {
            1 / 0
        }
        job.join()

    }