public interface

Consumer

com.facebook.imagepipeline.producers.Consumer<T>
Known Indirect Subclasses

Class Overview

Consumes data produced by Producer.

The producer uses this interface to notify its client when new data is ready or an error occurs. Execution of the image request is structured as a sequence of Producers. Each one consumes data produced by producer preceding it in the sequence.

For example decode is a producer that consumes data produced by the disk cache get producer.

The consumer is passed new intermediate results via onNewResult(isLast = false) method. Each consumer should expect that one of the following methods will be called exactly once, as the very last producer call:

  • onNewResult(isLast = true) if producer finishes successfully with a final result
  • onFailure if producer failed to produce a final result
  • onCancellation if producer was cancelled before a final result could be created

Implementations of this interface must be thread safe, as callback methods might be called on different threads.

Summary

Public Methods
abstract void onCancellation()
Called by a producer whenever it is cancelled and won't produce any more results
abstract void onFailure(Throwable t)
Called by a producer whenever it terminates further work due to Throwable being thrown.
abstract void onNewResult(T newResult, boolean isLast)
Called by a producer whenever new data is produced.
abstract void onProgressUpdate(float progress)
Called when the progress updates.

Public Methods

public abstract void onCancellation ()

Called by a producer whenever it is cancelled and won't produce any more results

public abstract void onFailure (Throwable t)

Called by a producer whenever it terminates further work due to Throwable being thrown. This method should not throw an exception.

public abstract void onNewResult (T newResult, boolean isLast)

Called by a producer whenever new data is produced. This method should not throw an exception.

In case when result is closeable resource producer will close it after onNewResult returns. Consumer needs to make copy of it if the resource must be accessed after that. Fortunately, with CloseableReferences, that should not impose too much overhead.

Parameters
isLast true if newResult is the last result

public abstract void onProgressUpdate (float progress)

Called when the progress updates.

Parameters
progress in range [0, 1]