android.widget
public
interface
android.widget.Adapter
An Adapter object acts as a bridge between an AdapterView and the
underlying data for that view. The Adapter provides access to the data items.
The Adapter is also responsible for making a View for
each item in the data set.
Known Indirect Subclasses
Summary
Details
Constants
public
static
final
int
IGNORE_ITEM_VIEW_TYPE
An item view type that causes the
AdapterView to ignore the item
view. For example, this can be used if the client does not want a
particular view to be given for conversion in
getView(int, View, ViewGroup).
Constant Value:
-1
(0xffffffff)
public
static
final
int
NO_SELECTION
Constant Value:
-2147483648
(0x80000000)
Public Methods
public
int
getCount()
How many items are in the data set represented by this Adapter.
public
Object
getItem(int position)
Get the data item associated with the specified position in the data set.
Parameters
position
| Position of the item whose data we want within the adapter's
data set. |
Returns
- The data at the specified position.
public
long
getItemId(int position)
Get the row id associated with the specified position in the list.
Parameters
position
| The position of the item within the adapter's data set whose row id we want. |
Returns
- The id of the item at the specified position.
public
int
getItemViewType(int position)
Get the type of View that will be created by
getView(int, View, ViewGroup) for the specified item.
Parameters
position
| The position of the item within the adapter's data set whose view type we
want. |
public
View
getView(int position, View convertView, ViewGroup parent)
Get a View that displays the data at the specified position in the data set. You can either
create a View manually or inflate it from an XML layout file. When the View is inflated, the
parent View (GridView, ListView...) will apply default layout parameters unless you use
inflate(int, android.view.ViewGroup, boolean)
to specify a root view and to prevent attachment to the root.
Parameters
position
| The position of the item within the adapter's data set of the item whose view
we want. |
convertView
| The old view to reuse, if possible. Note: You should check that this view
is non-null and of an appropriate type before using. If it is not possible to convert
this view to display the correct data, this method can create a new view. |
parent
| The parent that this view will eventually be attached to |
Returns
- A View corresponding to the data at the specified position.
public
int
getViewTypeCount()
Returns the number of types of Views that will be created by
getView(int, View, ViewGroup). Each type represents a set of views that can be
converted in getView(int, View, ViewGroup). If the adapter always returns the same
type of View for all items, this method should return 1.
This method will only be called when when the adapter is set on the
the AdapterView.
Returns
- The number of types of Views that will be created by this adapter
public
boolean
hasStableIds()
Indicated whether the item ids are stable across changes to the
underlying data.
Returns
- True if the same id always refers to the same object.
public
boolean
isEmpty()
Returns
- true if this adapter doesn't contain any data. This is used to determine
whether the empty view should be displayed. A typical implementation will return
getCount() == 0 but since getCount() includes the headers and footers, specialized
adapters might want a different behavior.
public
void
registerDataSetObserver(DataSetObserver observer)
Register an observer that is called when changes happen to the data used by this adapter.
Parameters
observer
| the object that gets notified when the data set changes.
|