kotlinx.coroutines

Interface CoroutineScope

All Known Subinterfaces:

ActorScope<E>, ProducerScope<E>

All Known Implementing Classes:

AbstractCoroutine, GlobalScope

public CoroutineScope

Defines a scope for new coroutines. Every coroutine builder is an extension on interface CoroutineScope and inherits its CoroutineScope.getCoroutineContext to automatically propagate both context elements and cancellation.

interface CoroutineScope should be implemented on entities with well-defined lifecycle that are responsible for launching children coroutines. Example of such entity on Android is Activity. Usage of this interface may look like this:

class MyActivity : AppCompatActivity(), CoroutineScope {
    lateinit var job: Job
    override val coroutineContext: CoroutineContext
        get() = Dispatchers.Main + job

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        job = Job()
    }

    override fun onDestroy() {
        super.onDestroy()
        job.cancel() // Cancel job on activity destroy. After destroy all children jobs will be cancelled automatically
    }

    /*
     * Note how coroutine builders are scoped: if activity is destroyed or any of the launched coroutines
     * in this method throws an exception, then all nested coroutines are cancelled.
     */
        fun loadDataFromUI() = launch { // <- extension on current activity, launched in the main thread
           val ioData = async(Dispatchers.IO) { // <- extension on launch scope, launched in IO dispatcher
               // blocking I/O operation
           }
           // do something else concurrently with I/O
           val data = ioData.await() // wait for result of I/O
           draw(data) // can draw in the main thread
        }
    }

See Also:

interface CoroutineScope, CoroutineScope.getCoroutineContext, interface CoroutineScope

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	CoroutineScope.DefaultImpls Defines a scope for new coroutines. Every coroutine builder is an extension on interface CoroutineScope and inherits its CoroutineScope.getCoroutineContext to automatically propagate both context elements and cancellation.

Method Summary

Modifier and Type	Method and Description
NonExistentClass	getCoroutineContext() Returns the context of this scope.

Method Detail

getCoroutineContext

NonExistentClass getCoroutineContext()

Returns the context of this scope.