com.hannesdorfmann.adapterdelegates4

Class AdapterDelegate<T>

java.lang.Object

com.hannesdorfmann.adapterdelegates4.AdapterDelegate<T>

Type Parameters:

T - The type of the data source

Direct Known Subclasses:

AbsFallbackAdapterDelegate, AbsListItemAdapterDelegate

public abstract class AdapterDelegate<T>
extends java.lang.Object

This delegate provide method to hook in this delegate to RecyclerView.Adapter lifecycle. This "hook in" mechanism is provided by AdapterDelegatesManager and that is the component you have to use.

Since:

1.0

Constructor Summary

Constructors

Constructor and Description
AdapterDelegate()

Method Summary

Modifier and Type	Method and Description
protected abstract boolean	isForViewType(T items, int position) Called to determine whether this AdapterDelegate is the responsible for the given data element.
protected abstract void	onBindViewHolder(T items, int position, androidx.recyclerview.widget.RecyclerView.ViewHolder holder, java.util.List<java.lang.Object> payloads) Called to bind the RecyclerView.ViewHolder to the item of the datas source set
protected abstract androidx.recyclerview.widget.RecyclerView.ViewHolder	onCreateViewHolder(android.view.ViewGroup parent) Creates the RecyclerView.ViewHolder for the given data source item
protected boolean	onFailedToRecycleView(androidx.recyclerview.widget.RecyclerView.ViewHolder holder) Called by the RecyclerView if a ViewHolder created by this Adapter cannot be recycled due to its transient state.
protected void	onViewAttachedToWindow(androidx.recyclerview.widget.RecyclerView.ViewHolder holder) Called when a view created by this adapter has been attached to a window.
protected void	onViewDetachedFromWindow(androidx.recyclerview.widget.RecyclerView.ViewHolder holder) Called when a view created by this adapter has been detached from its window.
protected void	onViewRecycled(androidx.recyclerview.widget.RecyclerView.ViewHolder holder) Called when a view created by this adapter has been recycled.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AdapterDelegate

public AdapterDelegate()

Method Detail

isForViewType

protected abstract boolean isForViewType(@NonNull
                                         T items,
                                         int position)

Called to determine whether this AdapterDelegate is the responsible for the given data element.

Parameters:

items - The data source of the Adapter

position - The position in the datasource

Returns:

true, if this item is responsible, otherwise false

onCreateViewHolder

@NonNull
protected abstract androidx.recyclerview.widget.RecyclerView.ViewHolder onCreateViewHolder(@NonNull
                                                                                                    android.view.ViewGroup parent)

Creates the RecyclerView.ViewHolder for the given data source item

Parameters:

parent - The ViewGroup parent of the given datasource

Returns:

The new instantiated RecyclerView.ViewHolder

onBindViewHolder

protected abstract void onBindViewHolder(@NonNull
                                         T items,
                                         int position,
                                         @NonNull
                                         androidx.recyclerview.widget.RecyclerView.ViewHolder holder,
                                         @NonNull
                                         java.util.List<java.lang.Object> payloads)

Called to bind the RecyclerView.ViewHolder to the item of the datas source set

Parameters:

items - The data source

position - The position in the datasource

holder - The RecyclerView.ViewHolder to bind

payloads - A non-null list of merged payloads. Can be empty list if requires full update.

onViewRecycled

protected void onViewRecycled(@NonNull
                              androidx.recyclerview.widget.RecyclerView.ViewHolder holder)

Called when a view created by this adapter has been recycled.

A view is recycled when a RecyclerView.LayoutManager decides that it no longer needs to be attached to its parent RecyclerView. This can be because it has fallen out of visibility or a set of cached views represented by views still attached to the parent RecyclerView. If an item view has large or expensive data bound to it such as large bitmaps, this may be a good place to release those resources.

RecyclerView calls this method right before clearing ViewHolder's internal data and sending it to RecycledViewPool. This way, if ViewHolder was holding valid information before being recycled, you can call RecyclerView.ViewHolder#getAdapterPosition() to get its adapter position.

Parameters:

holder - The ViewHolder for the view being recycled

onFailedToRecycleView

protected boolean onFailedToRecycleView(@NonNull
                                        androidx.recyclerview.widget.RecyclerView.ViewHolder holder)

Called by the RecyclerView if a ViewHolder created by this Adapter cannot be recycled due to its transient state. Upon receiving this callback, Adapter can clear the animation(s) that effect the View's transient state and return true so that the View can be recycled. Keep in mind that the View in question is already removed from the RecyclerView.

In some cases, it is acceptable to recycle a View although it has transient state. Most of the time, this is a case where the transient state will be cleared in RecyclerView.Adapter#onBindViewHolder(RecyclerView.ViewHolder, int) call when View is rebound to a new position. For this reason, RecyclerView leaves the decision to the Adapter and uses the return value of this method to decide whether the View should be recycled or not.

Note that when all animations are created by RecyclerView.ItemAnimator, you should never receive this callback because RecyclerView keeps those Views as children until their animations are complete. This callback is useful when children of the item views create animations which may not be easy to implement using an RecyclerView.ItemAnimator.

You should never fix this issue by calling holder.itemView.setHasTransientState(false); unless you've previously called holder.itemView.setHasTransientState(true);. Each View.setHasTransientState(true) call must be matched by a View.setHasTransientState(false) call, otherwise, the state of the View may become inconsistent. You should always prefer to end or cancel animations that are triggering the transient state instead of handling it manually.

Parameters:

holder - The ViewHolder containing the View that could not be recycled due to its transient state.

Returns:

True if the View should be recycled, false otherwise. Note that if this method returns true, RecyclerView will ignore the transient state of the View and recycle it regardless. If this method returns false, RecyclerView will check the View's transient state again before giving a final decision. Default implementation returns false.

onViewAttachedToWindow

protected void onViewAttachedToWindow(@NonNull
                                      androidx.recyclerview.widget.RecyclerView.ViewHolder holder)

Called when a view created by this adapter has been attached to a window.

This can be used as a reasonable signal that the view is about to be seen by the user. If the adapter previously freed any resources in onViewDetachedFromWindow those resources should be restored here.

Parameters:

holder - Holder of the view being attached

onViewDetachedFromWindow

protected void onViewDetachedFromWindow(@NonNull
                                        androidx.recyclerview.widget.RecyclerView.ViewHolder holder)

Called when a view created by this adapter has been detached from its window.

Becoming detached from the window is not necessarily a permanent condition; the consumer of an Adapter's views may choose to cache views offscreen while they are not visible, attaching an detaching them as appropriate.

Parameters:

holder - Holder of the view being detached