ValueEventListener

interfaceValueEventListener

Classes implementing this interface can be used to receive events about data changes at a location. Attach the listener to a location useraddValueEventListener.

Summary

Public functions

Unit

This method will be triggered in the event that this listener either failed at the server, or is removed as a result of the security and Firebase Database rules.

Unit

This method will be called with a snapshot of the data at this location.

Public functions

onCancelled

fun onCancelled(error: DatabaseError): Unit

This method will be triggered in the event that this listener either failed at the server, or is removed as a result of the security and Firebase Database rules. For more information on securing your data, see: Security Quickstart

Parameters
error: DatabaseError

A description of the error that occurred

onDataChange

fun onDataChange(snapshot: DataSnapshot): Unit

This method will be called with a snapshot of the data at this location. It will also be called each time that data changes.

Parameters
snapshot: DataSnapshot

The current data at the location

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Last updated 2025-07-21 UTC.