de.mrapp.android.util.view

Class AbstractViewRecycler<ItemType,ParamType>

java.lang.Object

de.mrapp.android.util.view.AbstractViewRecycler<ItemType,ParamType>

Type Parameters:

ItemType - The type of the items, which should be visualized by inflated views

ParamType - The type of the optional parameters, which may be passed when inflating a view

Direct Known Subclasses:

AttachedViewRecycler, ViewRecycler

public abstract class AbstractViewRecycler<ItemType,ParamType>
extends java.lang.Object

An abstract base class for all recyclers, which allow to cache views in order to be able to reuse them later, instead of inflating new instances. Such a recycler can for example be used to efficiently implement widgets similar to ListViews, whose children can be scrolled out of the visible screen area and therefore can be recycled. Each view must be associated with a corresponding item of an arbitrary generic type. By implementing the abstract class AbstractViewRecycler.Adapter, the views, which should be used to visualize a specific item, can be inflated and adapted in their appearance. The recycler supports to inflate different layouts for individual items by overriding an adapter's getViewType- and getViewTypeCount-method.

Since:

1.15.0

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AbstractViewRecycler.Adapter<ItemType,ParamType> An abstract base class for all adapters, which are responsible for inflating views, which should be used to visualize the items of a view recycler.

Constructor Summary

Constructors

Constructor and Description
AbstractViewRecycler(android.view.LayoutInflater inflater) Creates a new recycler, which allows to cache views in order to be able to reuse them later, instead of inflating new instances.

Method Summary

Modifier and Type	Method and Description
protected void	addUnusedView(android.view.View view, int viewType) Adds an unused view to the cache.
void	clearCache() Removes all unused views from the cache.
void	clearCache(int viewType) Removes all unused views, which correspond to a specific view type, from the cache.
protected java.util.Map<ItemType,android.view.View>	getActiveViews() Returns the map, which manages the views, which are currently used to visualize items.
AbstractViewRecycler.Adapter<ItemType,ParamType>	getAdapter() Returns the adapter, which is used to inflate and adapt the appearance of views.
android.content.Context	getContext() Returns the context, which is used by the view recycler.
protected android.view.LayoutInflater	getLayoutInflater() Returns the layout inflater, which is used to inflate views.
protected Logger	getLogger() Returns the logger, which is used by the recycler.
LogLevel	getLogLevel() Returns the log level, which is used for logging.
android.view.View	getView(ItemType item) Returns the view, which is currently used to visualize a specific item.
abstract <any>	inflate(ItemType item, boolean useCache, ParamType... params) Inflates the view, which is used to visualize a specific item.
<any>	inflate(ItemType item, ParamType... params) Inflates the view, which is used to visualize a specific item.
boolean	isCacheUsed() Returns, whether unused views are cached, or not.
boolean	isInflated(ItemType item) Returns, whether a view is currently inflated to visualize a specific item.
protected android.view.View	pollUnusedView(int viewType) Retrieves an unused view, which corresponds to a specific view type, from the cache, if any is available.
abstract void	remove(ItemType item) Removes a previously inflated view, which is used to visualize a specific item.
abstract void	removeAll() Removes all previously inflated views.
void	setAdapter(AbstractViewRecycler.Adapter<ItemType,ParamType> adapter) Sets the adapter, which should be used to inflate and adapt the appearance of views.
void	setLogLevel(LogLevel logLevel) Sets the log level, which should be used for logging.
void	useCache(boolean useCache) Sets, whether unused views should be cached, or not.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractViewRecycler

public AbstractViewRecycler(android.view.LayoutInflater inflater)

Creates a new recycler, which allows to cache views in order to be able to reuse them later, instead of inflating new instances.

Parameters:

inflater - The layout inflater, which should be used to inflate views, as an instance of the class LayoutInflater. The layout inflater may not be null

Method Detail

addUnusedView

protected final void addUnusedView(android.view.View view,
                                   int viewType)

Adds an unused view to the cache.

Parameters:

view - The unused view, which should be added to the cache, as an instance of the class View. The view may not be null

viewType - The view type, the unused view corresponds to, as an Integer value

pollUnusedView

protected final android.view.View pollUnusedView(int viewType)

Retrieves an unused view, which corresponds to a specific view type, from the cache, if any is available.

Parameters:

viewType - The view type of the unused view, which should be retrieved, as an Integer value

Returns:

An unused view, which corresponds to the given view type, as an instance of the class View or null, if no such view is available in the cache

getLogger

protected final Logger getLogger()

Returns the logger, which is used by the recycler.

Returns:

The logger, which is used by the recycler, as an instance of the class Logger. The logger may not be null

getLayoutInflater

protected final android.view.LayoutInflater getLayoutInflater()

Returns the layout inflater, which is used to inflate views.

Returns:

The layout inflater, which is used to inflate views, as an instance of the class LayoutInflater. The layout inflater may not be null

getActiveViews

protected java.util.Map<ItemType,android.view.View> getActiveViews()

Returns the map, which manages the views, which are currently used to visualize items.

Returns:

The map, which manages the views, which are currently used to visualize items, as an instance of the type Map. The map may not be null

inflate

public abstract <any> inflate(ItemType item,
                              boolean useCache,
                              ParamType... params)

Inflates the view, which is used to visualize a specific item.

Parameters:

item - The item, which should be visualized by the inflated view, as an instance of the generic type ItemType. The item may not be null

useCache - True, if an unused view should retrieved from the cache, if possible, false, if a new instance should be inflated instead

params - An array, which may contain optional parameters, as an array of the generic type ParamType or an empty array, if no optional parameters are available

Returns:

A pair, which contains the view, which is used to visualize the given item, as well as a boolean value, which indicates, whether a new view has been inflated, or if an unused view has been reused from the cache, as an instance of the class Pair. The pair may not be null

remove

public abstract void remove(ItemType item)

Removes a previously inflated view, which is used to visualize a specific item. If caching is enabled, the view will be put into a cache in order to be able to reuse it later.

Parameters:

item - The item, which is visualized by the view, which should be removed, as an instance of the generic type ItemType. The item may not be null

removeAll

public abstract void removeAll()

Removes all previously inflated views. If caching is enabled, all of these views will be added to a cache in order to be able to reuse them later.

inflate

public final <any> inflate(ItemType item,
                           ParamType... params)

Inflates the view, which is used to visualize a specific item. If possible, an unused view will be retrieved from the cache, instead of inflating a new instance.

Parameters:

item - The item, which should be visualized by the inflated view, as an instance of the generic type ItemType. The item may not be null

params - An array, which may contain optional parameters, as an array of the generic type ParamType or an empty array, if no optional parameters are available

Returns:

A pair, which contains the view, which is used to visualize the given item, as well as a boolean value, which indicates, whether a new view has been inflated, or if an unused view has been reused from the cache, as an instance of the class Pair. The pair may not be null

getContext

public final android.content.Context getContext()

Returns the context, which is used by the view recycler.

Returns:

The context, which is used by the view recycler, as an instance of the class Context. The context may not be null

getAdapter

public final AbstractViewRecycler.Adapter<ItemType,ParamType> getAdapter()

Returns the adapter, which is used to inflate and adapt the appearance of views.

Returns:

The adapter, which is used to inflate and adapt the appearance of views, as an instance of the class AbstractViewRecycler.Adapter or null, if no adapter is set

setAdapter

public final void setAdapter(AbstractViewRecycler.Adapter<ItemType,ParamType> adapter)

Sets the adapter, which should be used to inflate and adapt the appearance of views. Calling this method causes the cache to be cleared.

Parameters:

adapter - The adapter, which should be set, as an instance of the class AbstractViewRecycler.Adapter or null, if no adapter should be set

getLogLevel

public final LogLevel getLogLevel()

Returns the log level, which is used for logging.

Returns:

The log level, which is used for logging, as a value of the enum LogLevel. The log level may not be null

setLogLevel

public final void setLogLevel(LogLevel logLevel)

Sets the log level, which should be used for logging.

Parameters:

logLevel - The log level, which should be set, as a value of the enum LogLevel. The log level may not be null

getView

public final android.view.View getView(ItemType item)

Returns the view, which is currently used to visualize a specific item.

Parameters:

item - The item, whose view should be returned, as an instance of the generic type ItemType. The item may not be null

Returns:

The view, which is currently used to visualize the given item, as an instance of the type ItemType or null, if no such view is currently inflated

isInflated

public final boolean isInflated(ItemType item)

Returns, whether a view is currently inflated to visualize a specific item.

Parameters:

item - The item, which should be checked, as an instance of the generic type ItemType. The item may not be null

Returns:

True, if a view is currently inflated to visualize the given item, false otherwise

clearCache

public final void clearCache()

Removes all unused views from the cache.

clearCache

public final void clearCache(int viewType)

Removes all unused views, which correspond to a specific view type, from the cache.

Parameters:

viewType - The view type of the unused views, which should be removed from the cache, as an Integer value

isCacheUsed

public final boolean isCacheUsed()

Returns, whether unused views are cached, or not.

Returns:

True, if unused views are cached, false otherwise

useCache

public final void useCache(boolean useCache)

Sets, whether unused views should be cached, or not.

Parameters:

useCache - True, if unused views should be cached, false otherwise