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FocusObserver
abstract class FocusObserver
Subclass for observing changes to the focus state of an WindowId. You should use the same instance of this class for observing multiple WindowId objects, since this class is fairly heavy-weight -- the base class includes all of the mechanisms for connecting to and receiving updates from the window.
Summary
| Public constructors |
|
Construct a new observer.
|
| Public methods |
| abstract Unit |
Called when one of the monitored windows gains input focus.
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| abstract Unit |
Called when one of the monitored windows loses input focus.
|
Public constructors
FocusObserver
FocusObserver()
Construct a new observer. This observer will be configured so that all of its callbacks are dispatched on the current calling thread.
Public methods
onFocusGained
abstract fun onFocusGained(token: WindowId!): Unit
Called when one of the monitored windows gains input focus.
onFocusLost
abstract fun onFocusLost(token: WindowId!): Unit
Called when one of the monitored windows loses input focus.
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Last updated 2025-02-10 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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-02-10 UTC."],[],[],null,["# WindowId.FocusObserver\n\nAdded in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)\n\nFocusObserver\n=============\n\n*** ** * ** ***\n\nKotlin \\|[Java](/reference/android/view/WindowId.FocusObserver \"View this page in Java\") \n\n```\nabstract class FocusObserver\n```\n\n|---|------------------------------------------|\n| [kotlin.Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html) ||\n| ↳ | [android.view.WindowId.FocusObserver](#) |\n\nSubclass for observing changes to the focus state of an [WindowId](/reference/kotlin/android/view/WindowId). You should use the same instance of this class for observing multiple [WindowId](/reference/kotlin/android/view/WindowId) objects, since this class is fairly heavy-weight -- the base class includes all of the mechanisms for connecting to and receiving updates from the window.\n\nSummary\n-------\n\n| Public constructors ||\n|-----------------------------------------------------------------|---|\n| [FocusObserver](#FocusObserver())`()` Construct a new observer. |\n\n| Public methods ||\n|---------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| abstract [Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [onFocusGained](#onFocusGained(android.view.WindowId))`(`token:` `[WindowId](/reference/kotlin/android/view/WindowId)!`)` Called when one of the monitored windows gains input focus. |\n| abstract [Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [onFocusLost](#onFocusLost(android.view.WindowId))`(`token:` `[WindowId](/reference/kotlin/android/view/WindowId)!`)` Called when one of the monitored windows loses input focus. |\n\nPublic constructors\n-------------------\n\n### FocusObserver\n\nAdded in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) \n\n```\nFocusObserver()\n```\n\nConstruct a new observer. This observer will be configured so that all of its callbacks are dispatched on the current calling thread.\n\nPublic methods\n--------------\n\n### onFocusGained\n\nAdded in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) \n\n```\nabstract fun onFocusGained(token: WindowId!): Unit\n```\n\nCalled when one of the monitored windows gains input focus. \n\n### onFocusLost\n\nAdded in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) \n\n```\nabstract fun onFocusLost(token: WindowId!): Unit\n```\n\nCalled when one of the monitored windows loses input focus."]]
