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MutableLiveData

Artifact: androidx.lifecycle:lifecycle-livedata-core

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Added in 2.0.0

Kotlin |Java

public class MutableLiveData<T> extends LiveData

java.lang.Object
	androidx.lifecycle.LiveData
		androidx.lifecycle.MutableLiveData

Known direct subclasses

MediatorLiveData

MediatorLiveData

LiveData subclass which may observe other LiveData objects and react on OnChanged events from them.

LiveData which publicly exposes setValue and postValue method.

Parameters
`<T>`	The type of data hold by this instance

Summary

Public constructors
`MutableLiveData()` Creates a MutableLiveData with no value assigned to it.
`MutableLiveData(T value)` Creates a MutableLiveData initialized with the given `value`.

Public methods
`void`	`postValue(T value)` Posts a task to a main thread to set the given value.
`void`	`setValue(T value)` Sets the value.

Inherited methods

From androidx.lifecycle.LiveData

`@Nullable T`	`getValue()` Returns the current value.
`boolean`	`hasActiveObservers()` Returns true if this LiveData has active observers.
`boolean`	`hasObservers()` Returns true if this LiveData has observers.
`boolean`	`isInitialized()` Returns whether an explicit value has been set on this LiveData.
`void`	`@MainThread observe(@NonNull LifecycleOwner owner, @NonNull Observer<T> observer)` Adds the given observer to the observers list within the lifespan of the given owner.
`void`	`@MainThread observeForever(@NonNull Observer<T> observer)` Adds the given observer to the observers list.
`void`	`onActive()` Called when the number of active observers change from 0 to 1.
`void`	`onInactive()` Called when the number of active observers change from 1 to 0.
`void`	`@MainThread removeObserver(@NonNull Observer<T> observer)` Removes the given observer from the observers list.
`void`	`@MainThread removeObservers(@NonNull LifecycleOwner owner)` Removes all observers that are tied to the given `LifecycleOwner`.

Public constructors

MutableLiveData

Added in 2.0.0

public MutableLiveData()

Creates a MutableLiveData with no value assigned to it.

MutableLiveData

Added in 2.1.0

public MutableLiveData(T value)

Creates a MutableLiveData initialized with the given value.

Parameters
`T value`	initial value

Public methods

postValue

public void postValue(T value)

Posts a task to a main thread to set the given value. So if you have a following code executed in the main thread:

liveData.postValue("a");
liveData.setValue("b");

The value "b" would be set at first and later the main thread would override it with the value "a".

If you called this method multiple times before a main thread executed a posted task, only the last value would be dispatched.

Parameters
`T value`	The new value

setValue

public void setValue(T value)

Sets the value. If there are active observers, the value will be dispatched to them.

This method must be called from the main thread. If you need set a value from a background thread, you can use postValue

Parameters
`T value`	The new value

Content and code samples on this page are subject to the licenses described in the Content License. Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.

Last updated 2026-06-24 UTC.

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