belongs to Maven artifact com.android.support:recyclerview-v7:28.0.0-alpha1
SortedList.BatchedCallback
public
static
class
SortedList.BatchedCallback
extends Callback<T2>
| java.lang.Object | ||
| ↳ | android.support.v7.util.SortedList.Callback<T2> | |
| ↳ | android.support.v7.util.SortedList.BatchedCallback<T2> | |
A callback implementation that can batch notify events dispatched by the SortedList.
This class can be useful if you want to do multiple operations on a SortedList but don't want to dispatch each event one by one, which may result in a performance issue.
For example, if you are going to add multiple items to a SortedList, BatchedCallback call
convert individual onInserted(index, 1) calls into one
onInserted(index, N) if items are added into consecutive indices. This change
can help RecyclerView resolve changes much more easily.
If consecutive changes in the SortedList are not suitable for batching, BatchingCallback
dispatches them as soon as such case is detected. After your edits on the SortedList is
complete, you must always call dispatchLastEvent() to flush
all changes to the Callback.
Summary
Public constructors | |
|---|---|
SortedList.BatchedCallback(Callback<T2> wrappedCallback)
Creates a new BatchedCallback that wraps the provided Callback. |
|
Public methods | |
|---|---|
boolean
|
areContentsTheSame(T2 oldItem, T2 newItem)
Called by the SortedList when it wants to check whether two items have the same data or not. |
boolean
|
areItemsTheSame(T2 item1, T2 item2)
Called by the SortedList to decide whether two objects represent the same Item or not. |
int
|
compare(T2 o1, T2 o2)
Similar to |
void
|
dispatchLastEvent()
This method dispatches any pending event notifications to the wrapped Callback. |
Object
|
getChangePayload(T2 item1, T2 item2)
When |
void
|
onChanged(int position, int count, Object payload)
Called when |
void
|
onChanged(int position, int count)
Called by the SortedList when the item at the given position is updated. |
void
|
onInserted(int position, int count)
|
void
|
onMoved(int fromPosition, int toPosition)
|
void
|
onRemoved(int position, int count)
|
Inherited methods | |
|---|---|
From
class
android.support.v7.util.SortedList.Callback
| |
From
class
java.lang.Object
| |
From
interface
java.util.Comparator
| |
From
interface
android.support.v7.util.ListUpdateCallback
| |
Public constructors
SortedList.BatchedCallback
SortedList.BatchedCallback (Callback<T2> wrappedCallback)
Creates a new BatchedCallback that wraps the provided Callback.
| Parameters | |
|---|---|
wrappedCallback |
Callback: The Callback which should received the data change callbacks.
Other method calls (e.g. compare(Object, Object) from
the SortedList are directly forwarded to this Callback.
|
Public methods
areContentsTheSame
boolean areContentsTheSame (T2 oldItem,
T2 newItem)
Called by the SortedList when it wants to check whether two items have the same data
or not. SortedList uses this information to decide whether it should call
onChanged(int, int) or not.
SortedList uses this method to check equality instead of equals(Object)
so
that you can change its behavior depending on your UI.
For example, if you are using SortedList with a
RecyclerView.Adapter, you should
return whether the items' visual representations are the same or not.
| Parameters | |
|---|---|
oldItem |
T2: The previous representation of the object. |
newItem |
T2: The new object that replaces the previous one. |
| Returns | |
|---|---|
boolean |
True if the contents of the items are the same or false if they are different. |
areItemsTheSame
boolean areItemsTheSame (T2 item1,
T2 item2)
Called by the SortedList to decide whether two objects represent the same Item or not.
For example, if your items have unique ids, this method should check their equality.
| Parameters | |
|---|---|
item1 |
T2: The first item to check. |
item2 |
T2: The second item to check. |
| Returns | |
|---|---|
boolean |
True if the two items represent the same object or false if they are different. |
compare
int compare (T2 o1,
T2 o2)
Similar to compare(Object, Object), should compare two and
return how they should be ordered.
| Parameters | |
|---|---|
o1 |
T2: The first object to compare. |
o2 |
T2: The second object to compare. |
| Returns | |
|---|---|
int |
a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second. |
dispatchLastEvent
void dispatchLastEvent ()
This method dispatches any pending event notifications to the wrapped Callback. You must always call this method after you are done with editing the SortedList.
getChangePayload
Object getChangePayload (T2 item1,
T2 item2)
When areItemsTheSame(T2, T2) returns true for two items and
areContentsTheSame(T2, T2) returns false for them, SortedList.Callback calls this
method to get a payload about the change.
For example, if you are using SortedList.Callback with
RecyclerView, you can return the particular field that
changed in the item and your
ItemAnimator can use that
information to run the correct animation.
Default implementation returns null.
| Parameters | |
|---|---|
item1 |
T2: The first item to check. |
item2 |
T2: The second item to check. |
| Returns | |
|---|---|
Object |
A payload object that represents the changes between the two items. |
onChanged
void onChanged (int position,
int count,
Object payload)
Called when count number of items are updated at the given position.
| Parameters | |
|---|---|
position |
int: The position of the item which has been updated. |
count |
int: The number of items which has changed.
|
payload |
Object |
onChanged
void onChanged (int position,
int count)
Called by the SortedList when the item at the given position is updated.
| Parameters | |
|---|---|
position |
int: The position of the item which has been updated. |
count |
int: The number of items which has changed.
|
onInserted
void onInserted (int position,
int count)
| Parameters | |
|---|---|
position |
int |
count |
int |
onMoved
void onMoved (int fromPosition,
int toPosition)
| Parameters | |
|---|---|
fromPosition |
int |
toPosition |
int |
onRemoved
void onRemoved (int position,
int count)
| Parameters | |
|---|---|
position |
int |
count |
int |