Lifecycle.Event
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enum Lifecycle.Event : Enum
Represents a transition event triggered by a change in the LifecycleOwner's state.
Together with States, these events form a directed graph defining the valid lifecycle flow of a component:
+-------------+
| INITIALIZED |
+-------------+
|
| ON_CREATE
v
+---------+
| CREATED | ----------+
+---------+ |
| ^ |
ON_START | | ON_STOP |
v | | ON_DESTROY
+---------+ |
| STARTED | |
+---------+ |
| ^ |
ON_RESUME | | ON_PAUSE |
v | v
+---------+ +-----------+
| RESUMED | | DESTROYED |
+---------+ +-----------+
| See also | |
|---|---|
Lifecycle.State |
for the states resulting from these transition events. |
Summary
Enum Values |
|
|---|---|
ON_ANY |
A wildcard event constant that matches all |
ON_CREATE |
Dispatched when the |
ON_DESTROY |
Dispatched when the |
ON_PAUSE |
Dispatched when the |
ON_RESUME |
Dispatched when the |
ON_START |
Dispatched when the |
ON_STOP |
Dispatched when the |
Public companion functions |
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|---|---|---|
Lifecycle.Event? |
downFrom(state: Lifecycle.State)Returns the |
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Lifecycle.Event? |
downTo(state: Lifecycle.State)Returns the |
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Lifecycle.Event? |
upFrom(state: Lifecycle.State)Returns the |
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Lifecycle.Event? |
upTo(state: Lifecycle.State)Returns the |
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Public functions |
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|---|---|---|
Lifecycle.Event |
Returns the enum constant of this type with the specified name. |
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Array<Lifecycle.Event> |
values()Returns an array containing the constants of this enum type, in the order they're declared. |
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Public properties |
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|---|---|---|
EnumEntries<Lifecycle.Event> |
Returns an immutable |
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Lifecycle.State |
Returns the new |
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Enum Values
ON_ANY
val Lifecycle.Event.ON_ANY: Lifecycle.Event
A wildcard event constant that matches all Events.
ON_CREATE
val Lifecycle.Event.ON_CREATE: Lifecycle.Event
Dispatched when the LifecycleOwner enters the created state.
Called after the LifecycleOwner's onCreate returns. Transitions the lifecycle to State.CREATED.
ON_DESTROY
val Lifecycle.Event.ON_DESTROY: Lifecycle.Event
Dispatched when the LifecycleOwner is about to be destroyed.
Called before the LifecycleOwner's onDestroy is called. Transitions the lifecycle to State.DESTROYED.
ON_PAUSE
val Lifecycle.Event.ON_PAUSE: Lifecycle.Event
Dispatched when the LifecycleOwner is about to leave the resumed state.
Called before the LifecycleOwner's onPause is called. Transitions the lifecycle to State.STARTED.
ON_RESUME
val Lifecycle.Event.ON_RESUME: Lifecycle.Event
Dispatched when the LifecycleOwner enters the resumed state.
Called after the LifecycleOwner's onResume returns. Transitions the lifecycle to State.RESUMED.
ON_START
val Lifecycle.Event.ON_START: Lifecycle.Event
Dispatched when the LifecycleOwner enters the started state.
Called after the LifecycleOwner's onStart returns. Transitions the lifecycle to State.STARTED.
ON_STOP
val Lifecycle.Event.ON_STOP: Lifecycle.Event
Dispatched when the LifecycleOwner is about to leave the started state.
Called before the LifecycleOwner's onStop is called. Transitions the lifecycle to State.CREATED.
Public companion functions
downFrom
fun downFrom(state: Lifecycle.State): Lifecycle.Event?
Returns the Event that transitions down from the specified state to a lower state, or null if no transition exists.
Given state |
Returned Event |
State.DESTROYED |
null |
State.INITIALIZED |
null |
State.CREATED |
Event.ON_DESTROY |
State.STARTED |
Event.ON_STOP |
State.RESUMED |
Event.ON_PAUSE |
downTo
fun downTo(state: Lifecycle.State): Lifecycle.Event?
Returns the Event that transitions down into the specified target state, or null if no transition exists.
Target state |
Returned Event |
State.DESTROYED |
Event.ON_DESTROY |
State.INITIALIZED |
null |
State.CREATED |
Event.ON_STOP |
State.STARTED |
Event.ON_PAUSE |
State.RESUMED |
null |
upFrom
fun upFrom(state: Lifecycle.State): Lifecycle.Event?
Returns the Event that transitions up from the specified state to a higher state, or null if no transition exists.
Given state |
Returned Event |
State.DESTROYED |
null |
State.INITIALIZED |
Event.ON_CREATE |
State.CREATED |
Event.ON_START |
State.STARTED |
Event.ON_RESUME |
State.RESUMED |
null |
upTo
fun upTo(state: Lifecycle.State): Lifecycle.Event?
Returns the Event that transitions up into the specified target state, or null if no transition exists.
Target state |
Returned Event |
State.DESTROYED |
null |
State.INITIALIZED |
null |
State.CREATED |
Event.ON_CREATE |
State.STARTED |
Event.ON_START |
State.RESUMED |
Event.ON_RESUME |
Public functions
valueOf
fun valueOf(value: String): Lifecycle.Event
Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
| Throws | |
|---|---|
kotlin.IllegalArgumentException |
if this enum type has no constant with the specified name |
values
fun values(): Array<Lifecycle.Event>
Returns an array containing the constants of this enum type, in the order they're declared.
This method may be used to iterate over the constants.
The function returns a new instance of the array on every call. The array could be mutated, so working with it may also require defensive copying. Consider using entries property as a more efficient alternative returning an immutable list of enum entries.
Public properties
entries
val entries: EnumEntries<Lifecycle.Event>
Returns an immutable kotlin.enums.EnumEntries list containing the constants of this enum type, in the order they're declared.
targetState
val targetState: Lifecycle.State
Returns the new State of a Lifecycle that just reported this Event.