universum.studios.android.widget.adapter

Interface OnDataChangeListener<Adapter,Data>

Type Parameters:

Adapter - Type of the adapter to which will be this data change listener attached.

public interface OnDataChangeListener<Adapter,Data>

Listener which receives callbacks that may be used to listen for events before and after data change for a specific adapter.

This listener may be useful for example when there need to be saved and restored current scroll position of a collection view for which a specific adapter provides its data set. Then in such scenario we can save the current scroll position in onDataChange(Object, Object) and restore it in onDataChanged(Object, Object).

Both these callbacks should be guarantied to be called by the associated adapter if this listener is attached to it.

Author:

Martin Albedinsky

Method Summary

Modifier and Type	Method and Description
void	onDataChange(Adapter adapter, Data data) Invoked whenever the specified data are about to be changed in the given adapter.
void	onDataChanged(Adapter adapter, Data data) Invoked after onDataChange(Object, Object) callback has been fired and data change has been finished.

Method Detail

onDataChange

void onDataChange(@NonNull
                  Adapter adapter,
                  @Nullable
                  Data data)

Invoked whenever the specified data are about to be changed in the given adapter.

During duration of this call, the adapter still references the previous data.

Parameters:

adapter - The adapter of which data are about to be changed.

data - The data to be changed. May be null.

onDataChanged

void onDataChanged(@NonNull
                   Adapter adapter,
                   @Nullable
                   Data data)

Invoked after onDataChange(Object, Object) callback has been fired and data change has been finished.

When this callback is fired, the adapter already references the changed data.

Parameters:

adapter - The adapter where the data has been changed.

data - The changed data. May be null.