开始使用协程

用 RxJava

fetchUser()
    .subscribeOn(Schedulers.io())
    .observerOn(AndroidSchedulers.mainThread())
    .subscribe { user ->
        showUser(user)
    }

fun fetchUser(): Single<User> {
    // make network call
    // emit user
}

fun showUser(user: User) {
    // show user
}

用协程

fun fetchAndShowUser() {
    GlobalScope.launch(Dispatchers.Main) {
        val user = fetchUser() // fetch on IO thread
        showUser(user) // back on UI thread
    }
}

suspend fun fetchUser(): User {
    return withContext(Dispatchers.IO) {
        // make network call on IO thread
        // return user
    }
}

fun showUser(user: User) {
    // show user
}