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Android Components > Samples > Firefox Sync - Logins

A simple app showcasing the service-sync-logins component.


The main concepts shown in the sample app are:

  • Usage of the asynchronous result type SyncResult.
  • Login to Firefox Accounts that provides the necessary information to fetch the Logins from Firefox Sync.
  • Getting the list of Logins from Firefox Sync.

SyncResult usage

SyncResult represents a chainable asynchronous result, and is used as a convenient method of running potentially long-running tasks (eg. network requests, crypto operations) on threads outside of the UI thread.

A value or exception can be wrapped in an SyncResult:

val syncValue = SyncResult.fromValue(42)
val syncException = SyncResult.fromException(Exception("Something went wrong"))

One can attach OnValueListeners or OnExceptionListeners to an SyncResult. There are a few ways of chaining results in Kotlin:

  • Passing the listeners directly via then, with object expressions or otherwise:

     SyncResult.fromValue(42).then(object : OnValueListener<Integer, Void> {
     	override fun onValue(value: Integer): SyncResult<Void>? {
     		// handle the value
     		return SyncResult<Void>()
     }, object : OnExceptionListener<Void> {
     	override fun onException(exception: Exception): SyncResult<Void>? {
     		// handle the exception
     		return SyncResult<Void>()

    Since Java 6 does not support simple lambda syntax, this is one of the main ways to chain SyncResults in Java.

  • Passing lambdas via then:

     SyncResult.fromValue(42).then({ value: Int -> // valueListener
     	// handle the value
     	return SyncResult<Void>()
     }, { exception: Exception ->
     	// handle the exception
     	return SyncResult<Void>()
  • Completing a chain via whenComplete:

     SyncResult.fromValue(42).whenComplete { value: Integer ->
     	// handle the value

    Since whenComplete implies that the chain of promises has come to an end, there is no need to return another SyncResult at the end.


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