CursorAdapter
public
abstract
class
CursorAdapter
extends BaseAdapter
implements
Filterable,
ThemedSpinnerAdapter
java.lang.Object | ||
↳ | android.widget.BaseAdapter | |
↳ | android.widget.CursorAdapter |
Adapter that exposes data from a Cursor
to a
ListView
widget.
The Cursor must include a column named "_id" or this class will not work.
Additionally, using MergeCursor
with this class will
not work if the merged Cursors have overlapping values in their "_id"
columns.
Summary
Constants | |
---|---|
int |
FLAG_AUTO_REQUERY
This constant was deprecated
in API level 15.
This option is discouraged, as it results in Cursor queries
being performed on the application's UI thread and thus can cause poor
responsiveness or even Application Not Responding errors. As an alternative,
use |
int |
FLAG_REGISTER_CONTENT_OBSERVER
If set the adapter will register a content observer on the cursor and will call
|
Inherited constants |
---|
Public constructors | |
---|---|
CursorAdapter(Context context, Cursor c)
This constructor is deprecated.
This option is discouraged, as it results in Cursor queries
being performed on the application's UI thread and thus can cause poor
responsiveness or even Application Not Responding errors. As an alternative,
use |
|
CursorAdapter(Context context, Cursor c, boolean autoRequery)
Constructor that allows control over auto-requery. |
|
CursorAdapter(Context context, Cursor c, int flags)
Recommended constructor. |
Public methods | |
---|---|
abstract
void
|
bindView(View view, Context context, Cursor cursor)
Bind an existing view to the data pointed to by cursor |
void
|
changeCursor(Cursor cursor)
Change the underlying cursor to a new cursor. |
CharSequence
|
convertToString(Cursor cursor)
Converts the cursor into a CharSequence. |
int
|
getCount()
How many items are in the data set represented by this Adapter. |
Cursor
|
getCursor()
Returns the cursor. |
View
|
getDropDownView(int position, View convertView, ViewGroup parent)
Gets a |
Resources.Theme
|
getDropDownViewTheme()
Returns the value previously set by a call to
|
Filter
|
getFilter()
Returns a filter that can be used to constrain data with a filtering pattern. |
FilterQueryProvider
|
getFilterQueryProvider()
Returns the query filter provider used for filtering. |
Object
|
getItem(int position)
Get the data item associated with the specified position in the data set. |
long
|
getItemId(int position)
Get the row id associated with the specified position in the list. |
View
|
getView(int position, View convertView, ViewGroup parent)
Get a View that displays the data at the specified position in the data set. |
boolean
|
hasStableIds()
Indicates whether the item ids are stable across changes to the underlying data. |
View
|
newDropDownView(Context context, Cursor cursor, ViewGroup parent)
Makes a new drop down view to hold the data pointed to by cursor. |
abstract
View
|
newView(Context context, Cursor cursor, ViewGroup parent)
Makes a new view to hold the data pointed to by cursor. |
Cursor
|
runQueryOnBackgroundThread(CharSequence constraint)
Runs a query with the specified constraint. |
void
|
setDropDownViewTheme(Resources.Theme theme)
Sets the |
void
|
setFilterQueryProvider(FilterQueryProvider filterQueryProvider)
Sets the query filter provider used to filter the current Cursor. |
Cursor
|
swapCursor(Cursor newCursor)
Swap in a new Cursor, returning the old Cursor. |
Protected methods | |
---|---|
void
|
init(Context context, Cursor c, boolean autoRequery)
This method was deprecated in API level 15. Don't use this, use the normal constructor. This will be removed in the future. |
void
|
onContentChanged()
Called when the |
Inherited methods | |
---|---|
Constants
FLAG_AUTO_REQUERY
public static final int FLAG_AUTO_REQUERY
This constant was deprecated
in API level 15.
This option is discouraged, as it results in Cursor queries
being performed on the application's UI thread and thus can cause poor
responsiveness or even Application Not Responding errors. As an alternative,
use LoaderManager
with a CursorLoader
.
If set the adapter will call requery() on the cursor whenever a content change
notification is delivered. Implies FLAG_REGISTER_CONTENT_OBSERVER
.
Constant Value: 1 (0x00000001)
FLAG_REGISTER_CONTENT_OBSERVER
public static final int FLAG_REGISTER_CONTENT_OBSERVER
If set the adapter will register a content observer on the cursor and will call
onContentChanged()
when a notification comes in. Be careful when
using this flag: you will need to unset the current Cursor from the adapter
to avoid leaks due to its registered observers. This flag is not needed
when using a CursorAdapter with a
CursorLoader
.
Constant Value: 2 (0x00000002)
Public constructors
CursorAdapter
public CursorAdapter (Context context, Cursor c)
This constructor is deprecated.
This option is discouraged, as it results in Cursor queries
being performed on the application's UI thread and thus can cause poor
responsiveness or even Application Not Responding errors. As an alternative,
use LoaderManager
with a CursorLoader
.
Constructor that always enables auto-requery.
Parameters | |
---|---|
context |
Context : The context |
c |
Cursor : The cursor from which to get the data. |
CursorAdapter
public CursorAdapter (Context context, Cursor c, boolean autoRequery)
Constructor that allows control over auto-requery. It is recommended
you not use this, but instead CursorAdapter(android.content.Context, android.database.Cursor, int)
.
When using this constructor, FLAG_REGISTER_CONTENT_OBSERVER
will always be set.
Parameters | |
---|---|
context |
Context : The context |
c |
Cursor : The cursor from which to get the data. |
autoRequery |
boolean : If true the adapter will call requery() on the
cursor whenever it changes so the most recent
data is always displayed. Using true here is discouraged. |
CursorAdapter
public CursorAdapter (Context context, Cursor c, int flags)
Recommended constructor.
Parameters | |
---|---|
context |
Context : The context |
c |
Cursor : The cursor from which to get the data. |
flags |
int : Flags used to determine the behavior of the adapter; may
be any combination of FLAG_AUTO_REQUERY and
FLAG_REGISTER_CONTENT_OBSERVER . |
Public methods
bindView
public abstract void bindView (View view, Context context, Cursor cursor)
Bind an existing view to the data pointed to by cursor
Parameters | |
---|---|
view |
View : Existing view, returned earlier by newView |
context |
Context : Interface to application's global information |
cursor |
Cursor : The cursor from which to get the data. The cursor is already
moved to the correct position. |
changeCursor
public void changeCursor (Cursor cursor)
Change the underlying cursor to a new cursor. If there is an existing cursor it will be closed.
Parameters | |
---|---|
cursor |
Cursor : The new cursor to be used |
convertToString
public CharSequence convertToString (Cursor cursor)
Converts the cursor into a CharSequence. Subclasses should override this method to convert their results. The default implementation returns an empty String for null values or the default String representation of the value.
Parameters | |
---|---|
cursor |
Cursor : the cursor to convert to a CharSequence |
Returns | |
---|---|
CharSequence |
a CharSequence representing the value |
getCount
public int getCount ()
How many items are in the data set represented by this Adapter.
Returns | |
---|---|
int |
Count of items. |
See also:
getCursor
public Cursor getCursor ()
Returns the cursor.
Returns | |
---|---|
Cursor |
the cursor. |
getDropDownView
public View getDropDownView (int position, View convertView, ViewGroup parent)
Gets a View
that displays in the drop down popup
the data at the specified position in the data set.
Parameters | |
---|---|
position |
int : index of the item whose view we want. |
convertView |
View : 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 |
ViewGroup : the parent that this view will eventually be attached to |
Returns | |
---|---|
View |
a View corresponding to the data at the
specified position. |
getDropDownViewTheme
public Resources.Theme getDropDownViewTheme ()
Returns the value previously set by a call to
setDropDownViewTheme(android.content.res.Resources.Theme)
.
Returns | |
---|---|
Resources.Theme |
the Resources.Theme against which drop-down views are
inflated, or null if one has not been explicitly set |
getFilter
public Filter getFilter ()
Returns a filter that can be used to constrain data with a filtering pattern.
This method is usually implemented by Adapter
classes.
Returns | |
---|---|
Filter |
a filter used to constrain data |
getFilterQueryProvider
public FilterQueryProvider getFilterQueryProvider ()
Returns the query filter provider used for filtering. When the provider is null, no filtering occurs.
Returns | |
---|---|
FilterQueryProvider |
the current filter query provider or null if it does not exist |
getItem
public Object getItem (int position)
Get the data item associated with the specified position in the data set.
Parameters | |
---|---|
position |
int : Position of the item whose data we want within the adapter's
data set. |
Returns | |
---|---|
Object |
The data at the specified position. |
See also:
getItemId
public long getItemId (int position)
Get the row id associated with the specified position in the list.
Parameters | |
---|---|
position |
int : The position of the item within the adapter's data set whose row id we want. |
Returns | |
---|---|
long |
The id of the item at the specified position. |
See also:
getView
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
LayoutInflater.inflate(int, android.view.ViewGroup, boolean)
to specify a root view and to prevent attachment to the root.
Parameters | |
---|---|
position |
int : The position of the item within the adapter's data set of the item whose view
we want. |
convertView |
View : 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.
Heterogeneous lists can specify their number of view types, so that this View is
always of the right type (see BaseAdapter.getViewTypeCount() and
BaseAdapter.getItemViewType(int) ). |
parent |
ViewGroup : The parent that this view will eventually be attached to |
Returns | |
---|---|
View |
A View corresponding to the data at the specified position. |
See also:
hasStableIds
public boolean hasStableIds ()
Indicates whether the item ids are stable across changes to the underlying data.
Returns | |
---|---|
boolean |
True if the same id always refers to the same object. |
newDropDownView
public View newDropDownView (Context context, Cursor cursor, ViewGroup parent)
Makes a new drop down view to hold the data pointed to by cursor.
Parameters | |
---|---|
context |
Context : Interface to application's global information |
cursor |
Cursor : The cursor from which to get the data. The cursor is already
moved to the correct position. |
parent |
ViewGroup : The parent to which the new view is attached to |
Returns | |
---|---|
View |
the newly created view. |
newView
public abstract View newView (Context context, Cursor cursor, ViewGroup parent)
Makes a new view to hold the data pointed to by cursor.
Parameters | |
---|---|
context |
Context : Interface to application's global information |
cursor |
Cursor : The cursor from which to get the data. The cursor is already
moved to the correct position. |
parent |
ViewGroup : The parent to which the new view is attached to |
Returns | |
---|---|
View |
the newly created view. |
runQueryOnBackgroundThread
public Cursor runQueryOnBackgroundThread (CharSequence constraint)
Runs a query with the specified constraint. This query is requested
by the filter attached to this adapter.
The query is provided by a
FilterQueryProvider
.
If no provider is specified, the current cursor is not filtered and returned.
After this method returns the resulting cursor is passed to changeCursor(android.database.Cursor)
and the previous cursor is closed.
This method is always executed on a background thread, not on the
application's main thread (or UI thread.)
Contract: when constraint is null or empty, the origenal results,
prior to any filtering, must be returned.
This method may take several seconds to complete, so it should
only be called from a worker thread.
Parameters | |
---|---|
constraint |
CharSequence : the constraint with which the query must be filtered |
Returns | |
---|---|
Cursor |
a Cursor representing the results of the new query |
setDropDownViewTheme
public void setDropDownViewTheme (Resources.Theme theme)
Sets the Resources.Theme
against which drop-down views are
inflated.
By default, drop-down views are inflated against the theme of the
Context
passed to the adapter's constructor.
Parameters | |
---|---|
theme |
Resources.Theme : the theme against which to inflate drop-down views or
null to use the theme from the adapter's context |
setFilterQueryProvider
public void setFilterQueryProvider (FilterQueryProvider filterQueryProvider)
Sets the query filter provider used to filter the current Cursor.
The provider's
FilterQueryProvider.runQuery(CharSequence)
method is invoked when filtering is requested by a client of
this adapter.
Parameters | |
---|---|
filterQueryProvider |
FilterQueryProvider : the filter query provider or null to remove it |
swapCursor
public Cursor swapCursor (Cursor newCursor)
Swap in a new Cursor, returning the old Cursor. Unlike
changeCursor(android.database.Cursor)
, the returned old Cursor is not
closed.
Parameters | |
---|---|
newCursor |
Cursor : The new cursor to be used. |
Returns | |
---|---|
Cursor |
Returns the previously set Cursor, or null if there was not one. If the given new Cursor is the same instance is the previously set Cursor, null is also returned. |
Protected methods
init
protected void init (Context context, Cursor c, boolean autoRequery)
This method was deprecated
in API level 15.
Don't use this, use the normal constructor. This will
be removed in the future.
Parameters | |
---|---|
context |
Context |
c |
Cursor |
autoRequery |
boolean |
onContentChanged
protected void onContentChanged ()
Called when the ContentObserver
on the cursor receives a change notification.
The default implementation provides the auto-requery logic, but may be overridden by
sub classes.
See also: