universum.studios.android.widget.adapter.module

Class HeadersModule<H extends HeadersModule.Header>

java.lang.Object

universum.studios.android.widget.adapter.module.AdapterModule

universum.studios.android.widget.adapter.module.HeadersModule<H>

Type Parameters:

H - Type of the header items presented within data set of a subclass of this HeadersModule.

Direct Known Subclasses:

AlphabeticHeaders

public abstract class HeadersModule<H extends HeadersModule.Header>
extends AdapterModule

An AdapterModule implementation that specifies API for modules that may provide additional data set of headers for theirs associated adapter. To ensure that the associated adapter works properly, it is necessary to call some of HeadersModule API methods from within such adapter as it is shown below:

 public class SampleAdapter extends BaseAdapter implements ModuleAdapter {

      // Flag indicating item view type.
      private static final int VIEW_TYPE_ITEM = 0x00;

      // Flag indicating header view type.
      private static final int VIEW_TYPE_HEADER = 0x01;

      // Headers module holding the header items data set.
      private HeadersModule mHeadersModule;

      // ...

      public SampleAdapter(@NonNull Context context) {
          super(context);
          this.mHeadersModule = new HeadersModule();
          this.mHeadersModule.attachToAdapter(this);
      }

      @NonNull
      public int getItemCount() {
          // Expand current data set size with also size of headers data set.
          return super.getItemCount() + mHeadersModule.size();
      }

      @NonNull
      public Item getItem(int position) {
          // This is necessary because this adapter does not hold the entire data set but only
          // its items, so without this correction this call can throw IndexOutOfBoundsException
          // for the positions above super.getItemCount() because of implementation of getItemCount().
          return super.getItem(mHeadersModule.correctPosition(position));
      }

      @NonNull
      protected View onCreateView(@NonNull ViewGroup parent, int position) {
          switch (currentViewType()) {
              case VIEW_TYPE_ITEM:
                  return new View(mContext); // Create here view for adapter's item.
              case VIEW_TYPE_HEADER:
                  return mHeadersModule.createView(mLayoutInflater, parent, position);
          }
          return null;
      }

      @NonNull
      protected void onBindViewHolder(@NonNull Object viewHolder, int position) {
          switch (currentViewType()) {
              case VIEW_TYPE_ITEM:
                  // Bind here adapter's item.
                  break;
              case VIEW_TYPE_HEADER:
                  mHeadersModule.bindViewHolder(viewHolder, position);
                  break;
          }
      }

      // ...
 }
 

Author:

Martin Albedinsky

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	HeadersModule.Header Required interface for header items of HeadersModule.
static class	HeadersModule.SimpleHeader Simple implementation of HeadersModule.Header item for HeadersModule.

Nested classes/interfaces inherited from class universum.studios.android.widget.adapter.module.AdapterModule

AdapterModule.ModuleAdapter

Constructor Summary

Constructors

Constructor and Description
HeadersModule()

Method Summary

Modifier and Type	Method and Description
protected void	addHeader(H header, int position) Adds the given header at the specified position into the current headers data set of this module.
void	bindViewHolder(Object viewHolder, int position) Binds the given header viewHolder for the specified position.
void	clearHeaders() Clears the current headers data set of this module.
int	correctPosition(int position) Corrects the given position passed from the related adapter.
View	createView(LayoutInflater inflater, ViewGroup parent, int position) Creates the view for the header item at the specified position.
Object	createViewHolder(View view, int position) Creates the view holder for the given header view at the specified position.
H	getHeader(int position) Returns the header associated with the specified position from the current headers data set of this module.
SparseArray<H>	getHeaders() Returns the current headers data set of this module.
int	getHeadersCountBeforePosition(int position) Counts headers presented in the current headers data set before the requested position.
int	getHeaderStyleAttr() Returns the Xml style attribute specified via setHeaderStyleAttr(int).
boolean	isEmpty() Checks whether this module has some headers or not.
boolean	isHeaderAt(int position) Checks whether there is a header at the specified position or not.
protected void	removeHeaderAt(int position) Removes a header at the specified position from the current headers data set of this module.
void	setHeaderStyleAttr(int styleAttr) Sets an Xml attribute from the current theme, which contains a resource of style with attributes for header view which may be created via createView(LayoutInflater, ViewGroup, int).
int	size() Returns the count of headers in the current headers data set of this module.

Methods inherited from class universum.studios.android.widget.adapter.module.AdapterModule

assertAttachedToAdapterOrThrow, attachToAdapter, isAdapterNotificationEnabled, notifyAdapter, onAttachedToAdapter, requiresStateSaving, setAdapterNotificationEnabled

Methods inherited from class java.lang.Object

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

Constructor Detail

HeadersModule

public HeadersModule()

Method Detail

isEmpty

public boolean isEmpty()

Checks whether this module has some headers or not.

Returns:

True if this module does not have any headers, false otherwise.

See Also:

size()

size

public int size()

Returns the count of headers in the current headers data set of this module.

Returns:

Headers count.

See Also:

isEmpty()

addHeader

protected void addHeader(@NonNull
                         H header,
                         int position)

Adds the given header at the specified position into the current headers data set of this module. If there is already header at the specified position, the current one will be replaced by the given one.

Parameters:

header - The desired header to add.

position - The position at which should be header added.

See Also:

getHeader(int), removeHeaderAt(int)

isHeaderAt

public boolean isHeaderAt(int position)

Checks whether there is a header at the specified position or not.

Parameters:

position - The position to check.

Returns:

True if there is a header item at the specified position, false otherwise.

See Also:

getHeader(int)

getHeader

@Nullable
public H getHeader(int position)

Returns the header associated with the specified position from the current headers data set of this module.

Parameters:

position - Position of the desired header to obtain.

Returns:

Instance of the requested header at the specified position or null if there is no header item at the requested position.

See Also:

getHeaders(), isEmpty()

getHeaders

@NonNull
public SparseArray<H> getHeaders()

Returns the current headers data set of this module.

Returns:

Array of headers mapped to theirs positions.

See Also:

getHeader(int), isEmpty()

removeHeaderAt

protected void removeHeaderAt(int position)

Removes a header at the specified position from the current headers data set of this module.

Parameters:

position - The position at which should be header removed.

See Also:

addHeader(Header, int), clearHeaders()

clearHeaders

public void clearHeaders()

Clears the current headers data set of this module.

correctPosition

public int correctPosition(int position)

Corrects the given position passed from the related adapter. Position will be corrected (decreased) by count of the headers counted by getHeadersCountBeforePosition(int).

This should be used within the associated adapter's Adapter#getItem(int).

Parameters:

position - The position to correct.

Returns:

Corrected position which can be used in the associated adapter to properly/safely access items from its data set.

getHeadersCountBeforePosition

public int getHeadersCountBeforePosition(int position)

Counts headers presented in the current headers data set before the requested position.

Parameters:

position - The position, to which should be headers counted.

Returns:

The count of headers before the requested position.

setHeaderStyleAttr

public void setHeaderStyleAttr(@AttrRes
                               int styleAttr)

Sets an Xml attribute from the current theme, which contains a resource of style with attributes for header view which may be created via createView(LayoutInflater, ViewGroup, int).

Default value: R.attr.textViewStyle

Parameters:

styleAttr - Xml style attribute.

See Also:

getHeaderStyleAttr()

getHeaderStyleAttr

@AttrRes
public int getHeaderStyleAttr()

Returns the Xml style attribute specified via setHeaderStyleAttr(int).

Returns:

Xml style attribute.

See Also:

setHeaderStyleAttr(int)

createView

@NonNull
public View createView(@NonNull
                                 LayoutInflater inflater,
                                 @NonNull
                                 ViewGroup parent,
                                 int position)

Creates the view for the header item at the specified position.

Note, that the position passed here need to be the same position as passed to Adapter#getView(int, android.view.View, android.view.ViewGroup).

Parameters:

inflater - Layout inflater that may be used to create the requested view.

parent - A parent view, to resolve correct layout params for the newly creating view.

position - Position of the header from the current data set for which should be a new view created.

Returns:

A view corresponding to the header item at the specified position.

createViewHolder

@Nullable
public Object createViewHolder(@NonNull
                                          View view,
                                          int position)

Creates the view holder for the given header view at the specified position.

This method returns null by default as createView(LayoutInflater, ViewGroup, int) method creates by default instance of TextView.

Parameters:

view - The header view created via createView(LayoutInflater, ViewGroup, int) for which to create its holder.

position - The position for which has been the view created.

Returns:

Holder specific for the view or null if the view itself is a holder.

bindViewHolder

public void bindViewHolder(@NonNull
                           Object viewHolder,
                           int position)

Binds the given header viewHolder for the specified position.

Note, that the position passed here need to be the same position as passed to Adapter#getView(int, android.view.View, android.view.ViewGroup).

Parameters:

viewHolder - Holder for the specified position of which view should be bound with header's data.

position - The position for which to bind header data.