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interface Continuation
<TResult, TContinuationResult>
A function that is called to continue execution after completion of a Task
.
Summary
Public functions
fun then
(task: Task
<TResult!>): TContinuationResult!
Returns the result of applying this Continuation to task
.
To propagate failure from the completed Task call getResult
and allow the RuntimeExecutionException
to propagate. The RuntimeExecutionException will be unwrapped such that the Task returned by continueWith
or continueWithTask
fails with the original exception.
To suppress specific failures call getResult
and catch the exception types of interest:
task
.
continueWith
(
new
Continuation<String
,
String
> ()
{
@Override
public
String
then
(
Task<String>
task
)
{
try
{
return
task
.
getResult
(
IOException
.
class
);
}
catch
(
FileNotFoundException
e
)
{
return
"Not found"
;
}
catch
(
IOException
e
)
{
return
"Read failed"
;
}
}
}
To suppress all failures guard any calls to getResult
with isSuccessful
:
task
.
continueWith
(
new
Continuation<String
,
String
> ()
{
@Override
public
String
then
(
Task<String>
task
)
{
if
(
task
.
isSuccessful
())
{
return
task
.
getResult
();
}
else
{
return
DEFAULT_VALUE
;
}
}
}
Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License
, and code samples are licensed under the Apache 2.0 License
. For details, see the Google Developers Site Policies
. Java is a registered trademark of Oracle and/or its affiliates.
Last updated 2024-10-31 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2024-10-31 UTC."],[[["\u003cp\u003e\u003ccode\u003eContinuation\u003c/code\u003e is a function used to continue execution after a \u003ccode\u003eTask\u003c/code\u003e completes.\u003c/p\u003e\n"],["\u003cp\u003eIt defines a \u003ccode\u003ethen\u003c/code\u003e function that applies the continuation logic to the completed \u003ccode\u003eTask\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003ethen\u003c/code\u003e can propagate or suppress exceptions from the original \u003ccode\u003eTask\u003c/code\u003e based on how \u003ccode\u003egetResult\u003c/code\u003e is used.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eContinuation\u003c/code\u003e's result type can differ from the original \u003ccode\u003eTask\u003c/code\u003e's result type.\u003c/p\u003e\n"]]],[],null,["# Continuation\n============\n\nKotlin \\|[Java](/android/reference/com/google/android/gms/tasks/Continuation \"View this page in Java\") \n\n\n```\ninterface Continuation\u003cTResult, TContinuationResult\u003e\n```\n\n\u003cbr /\u003e\n\n*** ** * ** ***\n\nA function that is called to continue execution after completion of a [Task](/android/reference/kotlin/com/google/android/gms/tasks/Task). \n\n| Parameters |\n|-------------------------|--------------------------------|\n| `\u003cTResult\u003e` | the Task's result type |\n| `\u003cTContinuationResult\u003e` | the Continuation's result type |\n\n| See also |\n|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---|\n| [continueWith](/android/reference/kotlin/com/google/android/gms/tasks/Task#continueWith(com.google.android.gms.tasks.Continuation\u003cTResult,TContinuationResult\u003e)) | |\n| [continueWithTask](/android/reference/kotlin/com/google/android/gms/tasks/Task#continueWithTask(com.google.android.gms.tasks.Continuation\u003cTResult,com.google.android.gms.tasks.Task\u003cTContinuationResult\u003e\u003e)) | |\n\nSummary\n-------\n\n| ### Public functions |\n|------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| `TContinuationResult!` | [then](/android/reference/kotlin/com/google/android/gms/tasks/Continuation#then(com.google.android.gms.tasks.Task\u003cTResult\u003e))`(task: `[Task](/android/reference/kotlin/com/google/android/gms/tasks/Task)`\u003cTResult!\u003e)` Returns the result of applying this Continuation to `task`. |\n\nPublic functions\n----------------\n\n### then\n\n```\nfun then(task: Task\u003cTResult!\u003e): TContinuationResult!\n```\n\nReturns the result of applying this Continuation to `task`.\n\nTo propagate failure from the completed Task call [getResult](/android/reference/kotlin/com/google/android/gms/tasks/Task#getResult()) and allow the [RuntimeExecutionException](/android/reference/kotlin/com/google/android/gms/tasks/RuntimeExecutionException) to propagate. The RuntimeExecutionException will be unwrapped such that the Task returned by [continueWith](/android/reference/kotlin/com/google/android/gms/tasks/Task#continueWith(com.google.android.gms.tasks.Continuation\u003cTResult,TContinuationResult\u003e)) or [continueWithTask](/android/reference/kotlin/com/google/android/gms/tasks/Task#continueWithTask(com.google.android.gms.tasks.Continuation\u003cTResult,com.google.android.gms.tasks.Task\u003cTContinuationResult\u003e\u003e)) fails with the original exception.\n\nTo suppress specific failures call [getResult](/android/reference/kotlin/com/google/android/gms/tasks/Task#getResult(java.lang.Class\u003cX\u003e)) and catch the exception types of interest: \n\n```kotlin\ntask.continueWith(new Continuation\u003cString, String\u003e() {\n @Override\n public String then(Task\u003cString\u003e task) {\n try {\n return task.getResult(IOException.class);\n } catch (FileNotFoundException e) {\n return \"Not found\";\n } catch (IOException e) {\n return \"Read failed\";\n }\n }\n}\n```\n\nTo suppress all failures guard any calls to [getResult](/android/reference/kotlin/com/google/android/gms/tasks/Task#getResult()) with [isSuccessful](/android/reference/kotlin/com/google/android/gms/tasks/Task#isSuccessful()): \n\n```kotlin\ntask.continueWith(new Continuation\u003cString, String\u003e() {\n @Override\n public String then(Task\u003cString\u003e task) {\n if (task.isSuccessful()) {\n return task.getResult();\n } else {\n return DEFAULT_VALUE;\n }\n }\n}\n``` \n\n| Parameters |\n|-----------------------------------------------------------------------------------------|--------------------------------|\n| `task: `[Task](/android/reference/kotlin/com/google/android/gms/tasks/Task)`\u003cTResult!\u003e` | the completed Task. Never null |\n\n| Throws |\n|-----------------------------------------------------------------------------------------|------------------------------------|\n| [java.lang.Exception](https://developer.android.com/reference/java/lang/Exception.html) | if the result couldn't be produced |"]]
