i'm studying android by a book. according to the book, i need to create a repository to get data from the network response. and i had create a livedata to store info. here are the codes on my book.

object Repository {

    fun searchPlaces(query: String) = liveData(Dispatchers.IO) {
        val result = try {
            val placeResponse = SunnyWeatherNetwork.searchPlaces(query)
            if (placeResponse.status == "ok") {
                val places = placeResponse.places
                Result.success(places)
            } else {
                Result.failure(RuntimeException("response status is ${placeResponse.status}"))
            }
        } catch (e: Exception) {
            Result.failure<Place>(e)
        }
        emit(result)
    }

But when I copied the codes, i found that the second row's Dispatchers.IO was wrong. and i tried to import the kotlinx.coroutines.Dispatchers, the IDE can't find it. finally i abandoned the codes, and the app run successfully. i can't understand the specific principles

this is my build.gradle.

implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.9"

and how can i use the Dispatchers.IO?

CodePudding user response：

In order to use Dispatchers.IO you should add Kotlin Coroutines dependency. You can find it here. More info about Coroutines Dispatchers you can find here.

The coroutine context includes a coroutine dispatcher (see CoroutineDispatcher) that determines what thread or threads the corresponding coroutine uses for its execution. The coroutine dispatcher can confine coroutine execution to a specific thread, dispatch it to a thread pool, or let it run unconfined.

CodePudding user response：

Dispatchers.IO belongs to kotlinx-coroutines-core package.

Add kotlinx-coroutines-core implementation to your module's build.gradle

dependencies{
      def coroutinesVersion = '1.5.2-native-mt'
      implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:$coroutinesVersion"
}