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InvalidationTracker

public class InvalidationTracker
extends Object

java.lang.Object
   ↳ androidx.room.InvalidationTracker

InvalidationTracker keeps a list of tables modified by queries and notifies its callbacks about these tables.

Summary

Nested classes

class InvalidationTracker.Observer

An observer that can listen for changes in the database. 

Public methods

void addObserver(InvalidationTracker.Observer observer)

Adds the given observer to the observers list and it will be notified if any table it observes changes.

void refreshVersionsAsync()

Enqueues a task to refresh the list of updated tables.

void removeObserver(InvalidationTracker.Observer observer)

Removes the observer from the observers list.

Inherited methods

Public methods

addObserver

public void addObserver (InvalidationTracker.Observer observer)

Adds the given observer to the observers list and it will be notified if any table it observes changes.

Database changes are pulled on another thread so in some race conditions, the observer might be invoked for changes that were done before it is added.

If the observer already exists, this is a no-op call.

If one of the tables in the Observer does not exist in the database, this method throws an IllegalArgumentException.

This method should be called on a background/worker thread as it performs database operations.

Parameters
observer InvalidationTracker.Observer: The observer which listens the database for changes.

refreshVersionsAsync

public void refreshVersionsAsync ()

Enqueues a task to refresh the list of updated tables.

This method is automatically called when RoomDatabase.endTransaction() is called but if you have another connection to the database or directly use SupportSQLiteDatabase, you may need to call this manually.

removeObserver

public void removeObserver (InvalidationTracker.Observer observer)

Removes the observer from the observers list.

This method should be called on a background/worker thread as it performs database operations.

Parameters
observer InvalidationTracker.Observer: The observer to remove.