MutableLiveData

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

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.

`@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`.

Added in 2.0.0

public MutableLiveData()

Creates a MutableLiveData with no value assigned to it.

Added in 2.1.0

public MutableLiveData(T value)

Creates a MutableLiveData initialized with the given value.

Parameters
`T value`	initial value

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

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